Text preview for : Rheem H.S.I Heavy Duty Gas - 1172494.pdf part of Rheem 621265, 631265, 621275 and 631275 Service manual for Rheem Heavy Duty gas water heater.
Models 621265, 631265, 621275 and 631275
H.S.I = Hot Surface Ignition (does not use 'pilot' flame).
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Rheem Australia Pty Ltd
H.S.I Heavy Duty Gas
ABN 21 098 823 511
SERVICE INSTRUCTIONS
TM011
Reviisiion:: A Rev s on A Publliished:: March 06 Pub shed March 06
621265 631265 621275 631275
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Contents Safety Warning ....................................................................................................................2 Introduction ..........................................................................................................................2 Heater Model Identification ..................................................................................................2 Specifications.......................................................................................................................3 Preventative Maintenance ...................................................................................................3 Lighting Instructions .............................................................................................................4 Operation .............................................................................................................................4 Wiring Diagram 621265 / 631265 ........................................................................................9 Wiring Diagram 621275 .....................................................................................................10 Wiring Diagram 631275 - Manufactured Before 09/02/05..................................................11 Wiring Diagram 631275 - Manufactured After 09/02/05.....................................................12 Components and their Function.........................................................................................13 Product Changes ...............................................................................................................14 Common Faults .................................................................................................................16 Fault Finding - Chart 1 .......................................................................................................19 Fault Finding - Chart 2 .......................................................................................................22 Electronic Thermostat ........................................................................................................24 Electronic Thermostat Diagnosis ...................................................................................25 Electronic Thermostat Adjustment .................................................................................25 Temperature Sensor Set................................................................................................29 Fault Finding Chart 3 ..................................................................................................30 Ignition Module ..................................................................................................................31 Flue Damper - 621275 ONLY ............................................................................................39 Flue Damper Fault Finding - Chart 8..............................................................................40 Flue Damper Fault Finding - Chart 9..............................................................................42 Flue Damper - Bypass ...................................................................................................44 Combustion Fan, Pressure Switch and Relay - 631275 ONLY..........................................45 Fan Module Fault Finding - Chart 10 (631275 Manufactured Before 09/02/05) .............46 Fan Module Fault Finding - Chart 11 (631275 Manufactured After 09/02/05)................47 Fault Finding (No error code / No Operation) Chart 12 ...................................................51 Fault Finding (Intermittent Operation) - Chart 13 ...............................................................52 Fault Finding (Insufficient Hot Water) - Chart 14................................................................53 Fault Finding (Water Too Hot) - Chart 15...........................................................................54 Fault Finding (Leaking Water Heater) - Chart 16 ...............................................................55 Fluing Principals ................................................................................................................56 Component Replacement ..................................................................................................59 621265 Exploded View ......................................................................................................67 631265 Exploded View ......................................................................................................69 Burner Assembly Exploded View 265L ...........................................................................71 621275 Exploded View ......................................................................................................72 631275 Exploded View - Heater ........................................................................................74 631275 Exploded View Air Duct & Flue Terminal ...........................................................76 Burner Assembly Exploded View 275L ...........................................................................78 Gas Type Conversion Procedure.......................................................................................79 Rheem Water Heater (Excluding Solar) Warranty .............................................................81 Document Revision History................................................................................................82
TM011 H.S.I Heavy Duty Gas Service Instructions D.O.I: 03/06 This document is stored and maintained electronically by
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Safety Warning The purpose of these instructions is to provide sufficient information to allow a person with the skills required by the Regulatory Authorities to carry out effective repairs to a Rheem Gas Heavy Duty Water Heater in the minimum of time. Safety precautions or areas where extra care should be observed when conducting tests outlined in this service manual are indicated by print in bold italics and/or a warning symbol. Take care to observe the recommended procedure. If the supply cord is damaged, it must be replaced by the manufacturer or its service agent or a similarly qualified person in order to avoid a hazard. When conducting repairs to a gas appliance the gas train including injector sizes must not be altered or modified in any way. Certain diagnostic procedures outlined in these service instructions require "live" testing to be conducted. Personal Protective Equipment should be worn when conducting these tests to prevent the risk of electric shock. (Refer to Rheem Safety Procedure on electrical testing) Introduction The information provided in these instructions is based on the water heater being installed in accordance with AS5601 and the Installation Instructions provided with each water heater. Should you require further technical advice on a Rheem Heavy Duty Gas Water Heater, contact your nearest Rheem Service Department where genuine replacement parts are also available. Heater Model Identification All identification numbers are designed to convey detailed information about the heater to which it is attached. For example the model number consists of 7 digits and 1 letter. 6 6 Heavy Duty 2 - Internal 3 - External 0 - Pilot 1 - Electronic Ignition Capacity in Litres N - Natural Gas T - Town Gas P - Propane B - Butane Gas 0 - No Reference
Note: Model number, serial number and date of manufacture must be quoted in all correspondence.
2
1
265
N
0
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Specifications Model 621265 631265 621275 631275 680 680 680 680 800 800 800 800 1.13 1.13 1.13 1.13 2.75 2.75 2.75 2.75 0.75 0.75 0.75 0.75 3.5 3.5 3.5 3.5 82 82 82 82 84-90 84-90 84-90 84-90 3 x 1150 3 x 1150 3 x 1153 3 x 1153 38 x 600 Not fitted 76 x 845 76 x 845 RP1¼/32 RP1¼/32 RP1¼/32 RP1¼/32 RP¾/20 RP¾/20 RP¾/20 RP¾/20 1000 1000 1000 1000 RP¾/20 RP¾/20 RP¾/20 RP¾/20 2.90 2.90 3.80 3.80 4.80 4.80 6.50 6.50 2.50 2.50 3.20 3.20 8.60 8.60 10.50 10.50 2.50 2.50 2.65 2.65 0.85 0.85 0.90 0.90 0.32 0.32 0.50 0.50 110 110 200 200
Maximum Water With ECV Supply Pressure (kPa) Without ECV Natural Gas Minimum Gas Supply LP & Butane Gas Pressure (kPa) Town Gas Maximum Gas Supply Pressure (kPa) Maximum Thermostat Setting (ºC) ECO Cut Out Temperature (ºC) Anodes Qty X Length (mm) Flue Baffle Dia x Length (mm) Water Connections Diameter Diameter T&PR Valve Rating (kPa) Gas Connection LP Gas Natural Gas Burner Injector (mm) Butane Gas Town Gas LP & Butane Gas Burner Pressure (kPa) Natural Gas Town Gas Thermal Input (MJ) Preventative Maintenance
For peak performance it is suggested that the water heater be inspected prior to the winter period where light to medium hot water usage occurs and six monthly where medium to heavy usage occurs. 1. Check for discharge from the T&PR valve. Whilst the burner is off there should be no discharge of water. When the burner is operating, a small discharge of water may be evident. Operate the valve-easing lever to ensure the valve opens and resets properly. Always open and close the valve gently. The T&PR valve should be replaced at 5 yearly intervals. 2. Check the combustion chamber and burner for signs of scale deposits. Remove and clean if necessary. 3. Check the main burner pressure is as stated on the Rating Plate Remember to replace the test point screw. 4. Check main burner flame to ensure all parts ignite readily and that the flame is blue with little or no yellowing of the tips. If necessary adjust the interrupter screw to eliminate yellowing without inducing a harsh noisy blue flame. 5. Check the drain cock is not leaking. 6. Check for sludge build up and if necessary drain and flush tank. 7. Inspect and if necessary replace anodes. (Hard water areas only) 8. Check for signs of excessive corrosion on the jacket. 9. Check operation of auxiliary equipment i.e. circulator 10. Warn customer of the danger of using flammable materials or aerosol spray packs near the water heater. Aerosols and harsh chemicals can cause premature failure of water heater components.
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Lighting Instructions The water heater incorporates an automatic ignition system. Switch on the power, when the controlling thermostat registers heating is required the ignition sequence will commence automatically. Should the unit fail to light after 4 ignition attempts the electronic control system will enter lockout mode. Operation Heat Mode 1. Thermostat contacts close to call for heat 621265 and 631265 Power supplied to ignition control module. 621275 Flue damper opens and proving limit switch closes supplying power to ignition control module. NOTE: During standby (thermostat contacts open) the flue damper is held closed by power being applied to the flue damper motor. 631275 Manufactured Before 09/02/05 Combustion fan and relay energised. Proving switch contacts on pressure switch close when combustion pressure is achieved supplying power to ignition control module. Manufactured After 09/02/05 Power supplied to ignition control module. The ignition module checks (position proves) pressure switch is open and if so then supplies power to the combustion fan and then checks that the pressure switch has closed. 2. The hot surface igniter warm up period commences (20 seconds) 3. At completion of the warm up period the gas valve is energised and opens to allow gas to the main burner where ignition takes place. Note: A door switch is wired in series with the gas control on the 631275. The gas control will not operate if the access door is not in place. 4. The igniter is de-energised at the conclusion of the igniter activation period (I.A.P), normally referred to as the ignition proving time, which is 2.5 seconds or proof of flame. 5. Thermostat contacts open when set temperature is achieved. 621265 and 631265 Gas valve is de-energised cutting supply of gas to the burner 621275 Flue damper closes and proving limit switch contacts open. Gas valve is deenergised cutting supply of gas to the burner. 631275 Manufactured Before 09/02/05 Combustion fan and relay de-energised. Proving switch contacts on pressure switch open when the pressure drops below required combustion pressure. Gas valve is de-energised cutting supply of gas to the burner. Manufactured After 09/02/05 Combustion fan and gas valve is de-energised cutting supply of gas to the burner. Proving switch contacts on pressure switch open when the pressure drops below required combustion pressure.
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Retry Mode If flame is not sensed during the Ignition Activation Period (2.5 seconds) 1. The gas valve is de-energised. 2. The system waits 5 minutes to allow for the escape of unburnt gas. 3. The normal ignition sequence is retried. 4. Igniter period remains at 20 seconds with the control re-entering "learn mode".
5. The ignition control module will enter "retry lock out", 1 flash, if burner ignition is
unsuccessful after 3 attempts. Recycle Mode (Within a Thermostat Cycle) If flame is established then lost after the I.A.P i.e. after flame was sensed 1. The gas valve is de-energised. 2. Normal ignition sequence is started 3. No increase in igniter warm up time. 4. The ignition control module will enter "retry lock out", 1 flash, if burner ignition is unsuccessful after 3 attempts. Note: Infinite recycles and three ignition retries are allowed during any one (1) thermostat cycle. Normal Mode After flame has been sensed, the ignition control module enters the normal operating loop where all inputs are continuously checked. Lockout or Wait Mode When the ignition control module enters "lock out" or "wait" modes the condition can be cleared by turning the power off and then on again at the power point or by pressing the reset button for approximately 1 second. Note: If the fault continues to exist i.e. an open circuit igniter, the module will immediately re-enter the lockout or wait mode and display a fault code. Safety Features If the ignition control module is energised and flame is detected when the gas valve is deenergised, the ignition control module enters the "safety wait mode", 5 flashes. If the gas valve is energised 4 consecutive times and flame is not sensed within the I.A.P, the ignition control module will enter "retry lock out", 1 flash. In the event of a flame failure during a heating cycle the gas valve is closed in 0.9 seconds. If flame is not detected within 2.5 seconds from the commencement of the trial for ignition period the gas valve is closed.
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Heating Cycle Flow Chart - 621265, 631265, 621275 & 631275 (Before 09/02/05)
Connect power
Rectify fault 621265 631265 Controlling thermostat contacts close 621275 631275 pre 09/02/05 Power supplied to flue damper relay Power supplied to combustion fan module Flue damper opens Fan starts Pressure switch closes Power supplied to ignition module
Cold start up
Internal safety check ok?
NO
Solid LED (lock out)
Can module be reset?
YES
Event counter limit exceeded
NO YES Warm start up
Control module internal failure
Auto reset
Polarity check ok? YES
NO
6 Flashes (wait mode)
Check repeated continuously
Polarity check ok?
YES
NO
False flame detected? NO
YES
5 Flashes (wait mode)
Check repeated continuously
False flame detected?
NO
YES Igniter circuit ok?
Igniter circuit ok? YES
NO
4 Flashes (wait mode)
Recheck igniter circuit three minutes later
YES
NO 5 minutes later Hot surface igniter off Gas valve closed
Hot surface igniter energised Gas valve energised
Flame detected?
NO Within 2.5 seconds
No of ignition retries >4 YES
NO
YES Hot surface igniter off Continuous check mode entered
1 Flash (Lock out) Frequency check ok?
YES
Frequency check ok?
NO
Rapid flash
YES
DC current approx 4µA AC current < 6.5µA Flame detected? YES 7 Flashes (wait mode)
NO
NO Gas valve closed
Flame detected?
NO
YES
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Heating Cycle Flow Chart - 631275 (After 09/02/05)
Connect power Controlling thermostat contacts close
Power supplied to ignition module Cold start up
Rectify fault
Internal safety check ok?
NO
Solid LED (lock out)
Can module be reset?
YES
Event counter limit exceeded Control module internal failure Auto reset
NO YES Warm start up
False flame detected?
YES
5 Flashes (wait mode)
Check repeated continuously
False flame detected?
NO
NO pressure switch open? YES Fan energised
YES pressure switch open?
NO
2 Flashes (wait mode)
Check repeated continuously
YES
NO
pressure switch closed? YES
NO
3 Flashes (wait mode)
Check repeated continuously
pressure switch closed?
YES
NO 6 Flashes (wait mode) Check repeated continuously Polarity check ok?
Polarity check ok? YES
NO
YES
NO Igniter circuit ok?
Igniter circuit ok? YES
NO
4 Flashes (wait mode)
Recheck igniter circuit three minutes later
YES
NO 5 minutes later Hot surface igniter off Gas valve closed
Hot surface igniter energised Gas valve energised
Flame detected?
NO Within 2.5 seconds
No of ignition retries >4 YES
NO
YES Hot surface igniter off Continuous check mode entered
1 Flash (Lock out) Frequency check ok?
YES
Frequency check ok?
NO
Rapid flash
YES
DC current approx 4µA AC current < 6.5µA Flame detected? YES 7 Flashes (wait mode) NO
NO Gas valve closed
Flame detected?
NO
YES
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Burner Extinction Cycle Flow Chart
Thermostat contacts open 631275 Pre 09/02/05 Combustion fan relay de-energized 621265 631265 631275 After 09/02/05 Ignition module de-energized
621275
Flue damper relay de-energized
Flue damper motor energized
Combustion fan motor de-energized Pressure switch contacts to "normally closed" position once fan stops
Combustion fan de-energized & Gas valve closed
Flue damper closed
Burner extinguished
Ignition module de-energized Pressure switch contacts to "normally open" position once fan stops
Gas valve closed
Burner extinguished
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Wiring Diagram 621265 / 631265
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Wiring Diagram 621275
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Wiring Diagram 631275 - Manufactured Before 09/02/05
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Wiring Diagram 631275 - Manufactured After 09/02/05
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Components and their Function Gas Control Valve: The gas valve is a White Rodgers model 36C90H-408 220/240 volt AC double solenoid valve suitable for use with electronic controllers. An insulated one-shot thermal fuse is incorporated into one of the solenoid leads to act as a cut out in the event of excessive heat spillage from the combustion chamber. The thermal fuse will open circuit at temperatures of 90ºC to 100ºC. The gas valve is gas type convertible (refer to gas type conversion procedure on page 79. Ignition Module: The ignition module controls the operation of the burner ignition sequence. Each step of the sequence is timed by the controller, in the event of a malfunction the controller will enter either a `wait' or `lock out' mode and display an error code on an LED indicated by a series of flashes (refer to page 31). If the burner fails to light during the ignition sequence the controller will attempt to relight the burner 3 times. If the third reattempt is unsuccessful the controller will "lock out". Operating temperature range is 0ºC to 60ºC. The controller will operate on a line voltage of 187-264 volts AC. Where the line frequency (50 or 60 Hz) varies by more than +/- 5% the controller will not operate. Flue Damper (621275 ONLY): The flue damper is designed to minimise heat loss through the flue system during standby. The butterfly flap is not pierced as the H.S.I heavy-duty range does not utilize a standing pilot. Prior to the ignition sequence commencing the flue damper is rotated to the open position, two limit switches, 1 primary and 1 safety, are incorporated into the flue damper to `prove' the damper is open. The flue damper is motor driven closed; a spring mounted on the shaft opens the damper. A replaceable 1.6 amp fuse is mounted on the damper enclosure to protect the damper PCB from damage should the gas control and ignition control module fail. Igniter and Flame Probe: The igniter rod is manufactured from Silicon Nitrate. When power is applied, the rod glows to ignite the gas. This system is known as hot surface ignition (H.S.I.) The flame rod is manufactured from Canthal-D and forms part of the flame proving system. A small electric current is passed from the ignition module to the flame rod and then through the flame to earth. This is known as flame rectification. Note: The flame proving system will only work when the water heater is connected to a correctly polarised and earthed neutral mains supply. Over Temperature Energy Cut Out (E.C.O.): A temperature-sensing device that automatically cuts off the power supply to prevent excessive water temperature occurring. This device will not reset automatically, however it can be manually reset once temperatures have fallen to a safe level. Anode (sacrificial): A metal alloy electrode which, by galvanic action, protects the inner cylinder from corrosion.
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Temperature and Pressure Relief Valve: A valve designed to provide automatic relief by discharging water in case of excessive temperature, pressure or both. Never fit a T&PR Valve with a pressure rating greater than that indicated on the product-rating label, do NOT use reconditioned T&PR valves. Delivery Tube (Dip Tube): A polypropylene tube fitted inside the water heater cylinder to conduct water from the highest point to the outlet connection. It also acts as a fitting liner. Inlet Diffuser: A device installed in the cold water inlet of the water heater to help control temperature stratification within the cylinder. Flue Baffle: A baffle inserted into the water heater flue tube that slows the passage of flue gases to ensure maximum heat transfer to the stored water. Draught Diverter (indoor models): A cowl installed at the top of the water heater between the primary flue and secondary flue to help prevent adverse draughts affecting the gas burner operation. Combustion Fan (631275 only): A fan and electric motor combination, installed in the air duct to provide sufficient primary air for combustion. Pressure Switch (631275 only): A device sensitive to air pressure incorporating a microswitch. When sufficient pressure is created by the combustion fan the micro-switch contacts close supplying power to the ignition control module (models manufactured before 09/02/05 or closing a proving circuit in the ignition module (models manufactured after 09/02/05) Relay (631275 Manufactured before 09/02/05 only): An electric coil operating a pair of single throw contacts. The relay is interlocked electrically with the combustion fan and pressure switch as a safety measure to prevent operation of the gas burner in the event the pressure switch, combustion fan or both have failed. Product Changes Controlling Thermostat (All models) · · An AKO electronic thermostat has replaced the Robertshaw mechanical thermostat, allowing accurate temperature and differential control. Two temperature sensors (thermistors) mounted in wells at the same heights as the inlet and outlet of the water heater are utilized to detect the water temperature at the top and bottom of the tank. A small electronic circuit board installed in the sensor wiring offsets the cold sensor reading to provide the average temperature for the entire tank. The electronic thermostat features an external LED display indicating the water temperature, or in the event of a failure, an error code (refer to page 25).
·
Viewing Windows · Viewing windows have been added to all models to allow the LED on the ignition module to be observed without the need to remove any covers
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Ignition Module (All Models Except 631275 Manufactured After 09/02/05) The 50A72-298 ignition module replaces the 50A72-208. The new module features · 3 re-ignition attempts, with a 5-minute delay between each attempt · Volatile memory. Turning the power off and on at the power point will now reset the ignition module. A reset button is also fitted on the ignition module. · With the exception of ignition failure (1 flash lockout) the ignition module will enter a `wait' mode when a fault is detected and will automatically reset if the fault clears.
Ignition Module (631275 Manufactured After 09/02/05) The 50A72-178 ignition module replaces the 50A72-298. These two ignition modules are not interchangeable, to prevent fitment of the incorrect module the wiring loom plugs are not compatible. The new ignition module · Utilises an internal method of checking the pressure switch position (position proving) and also supplies power to the combustion fan rendering the relay and its associated wiring obsolete. · Eliminates the need for a proving relay in the fan module · Has two additional fault codes (2 flashes and 3 flashes) both relating to the pressure switch position (refer to page 31). All other fault codes remain the same as the earlier ignition module. · Has a 30 second delay before energising the fan motor, eliminating fan run on problems associated with power brown outs (refer to page 45). To overcome fan run on problems, it is possible to convert a 631275 fitted with a 50A72298 ignition module to use the 50A72-178 ignition module. For full instructions refer to Technical Bulletin TB05 011. Limit Thermostat · The auto reset upper limit thermostat has been deleted and replaced with a manual reset ECO thermostat located where the mechanical thermostat was positioned in past models.
Flue Damper (621275 Only) · A replaceable 1.6 amp fuse has been added to the flue damper control circuit. In the event the gas valve or ignition module suffers a major electrical failure the fuse will blow protecting the flue damper control circuit from any resulting short circuit or power surge.
Access Door (631275) · A small indentation has been added to the access door to provide a more positive action on the door switch. This modification is to overcome intermittent contact resulting in fan run on without burner operation.
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Common Faults When a complaint is lodged about the performance of a hot water system there are a number of causes that should be checked and eliminated. In an attempt to pinpoint the most likely cause it is important to discuss with the customer their reasons for the complaint, the duration of the problem, any change in circumstances or usage and recent weather conditions. This information in conjunction with the following listed common complaints will assist in locating the most likely cause. All procedures assume there is water flowing through the water heater. Water hammer A water heater will not cause water hammer, however valves associated with the water heater may be the source of the problem i.e. cold-water stopcock, non-return valve, T&PR valve or relief valve. Most water hammer problems are associated with plumbing, hot and cold, or appliances i.e. solenoid valves, ball cocks, loose pipes, sharp angles in pipe work, faulty or worn valve parts or neighbouring equipment. High water pressure areas will have more complaints of this nature and the use of a pressure-limiting valve (PLV) to reduce the household cold-water pressure will usually solve most problems. Excessive hot water usage The complaints of insufficient hot water and no hot water can on many occasions be attributed to hot water usage exceeding the capacity of the water heater to provide hot water. When first attending a call of this nature it is essential to establish the probable hot water usage by querying the usage habits of the household and compare this with the potential delivery of the model water heater installed. It can then be established if the usage is within or outside the capacity of the model. The areas to look at for excessive usage are: 1. Automatic washing machines. 2. Showers exceeding 11 litres per minute for mixed water and 5 minutes in duration. 3. Two or more showers operating at the same time. 4. Change of occupancy or number of persons increased. 5. High water pressure area. (Excessive T&PR discharge) 6. Plumbing leaks Discoloured water 1. This may be the result of discoloured water entering from the cold water mains. Check if the cold water is also discoloured. 2. Brown coloured water will generally indicate that the anode has been depleted or the water heater is near the end of its useful life. 3. Milky coloured water is generally air in suspension and will disperse of its own accord. In very hard water areas where anode gassing occurs, milky water may be evident. The use of a blue anode should overcome this problem.
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Hot water plumbing leaks If hot water has not been used for a period of time, feeling the temperature of the hot water line may give an indication of water flow if the pipe is warm. The method of checking for plumbing leaks is: 1. Turn off the stopcock on the cold water supply to the water heater. 2. Open a hot tap to ensure the flow of water stops. This will confirm the stopcock is operating correctly. 3. Turn off the hot tap. 4. Turn on the stopcock to make up the water pressure in the cylinder, and then turn the stopcock off again. 5. Wait approximately 5 minutes then do either of the following: a. With your ear close to the stopcock turn it on slightly and listen for any water passing. If there are no leaks, water should not pass. b. Open a hot tap while listening for any pressure release. If there is a pressure release there will be no leaks in the plumbing system. Mixing or crossed connections If an automatic dishwasher, washing machine, flick mixer tap, tempering valve or thermostatic mixing valve is installed there is always the possibility that the cold water could mix with the hot water through a faulty or incorrectly installed valve. This is referred to as a cross connection. The complaints of insufficient hot water, water too cold or excessive discharge from the T&PR valve may be attributed to a cross connection. The method of checking for a cross connection is: 1. Turn off the stopcock on the cold water supply to the water heater. 2. Open a hot tap. If water flow is persistent and cold a cross connection exists. Manifolding - Headers Very often complaints surrounding insufficient hot water in commercial installations can be attributed to poor manifolding. In order for the water heaters to operate simultaneously the water flow through all the cylinders must be the same to ensure the temperature drop is equal. In a worst-case scenario it is possible for 2 or 3 of the water heaters in a bank to almost never operate. This results in an overall loss of heat input to the water moving through the building and can be confused as the installation being undersized or a malfunction of the water heaters. The principle of Equa-Flow is to ensure the demand on each water heater in the bank is the same as any other. To achieve this, the following are necessary:
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1. The cold water manifold must be designed to balance the flow to each unit i.e. each branch line must be the same diameter and length and be fitted with identical ball or gate valves.
2. The hot water manifold must be designed to balance the flow from each unit i.e. each branch line must be the same diameter and length and be fitted with identical ball or gate valves.
In Line Manifold Manifolding - Types 1. All the water heaters must be of the same size and capacity. 2. The first heater supplied from the cold (inlet) manifold must be the last heater supplying the hot (outlet) manifold (refer to examples opposite and below).
Back to Back Manifold
Angle Manifold
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Fault Finding - Chart 1
Power Supply 1.1
Is the thermostat display blank?
YES
Is there power at the terminal block? NO
Test 1 YES 1
Test 2 NO Increase the set point above the current water temperature by at least 5 degrees YES Test 3 Are the thermostat contacts closed? NO Is the water temperature at or above the thermostat setting? Test 4 Is there power at the GPO? NO Yes Replace cord
Refer to electrician
1.2 YES Test 5 Is there power at the ignition module?
NO
2
YES
Does the burner light?
NO
Refer to ignition module section
YES
Is the complaint for intermittent operation?
YES
3
NO
Insufficient hot water
4
Water too hot
5
Leaking Is a power flue or mechanical venting system installed? Test 6 Is the sail or pressure switch closed?
6
YES
NO
Refer to installer
YES
621275
Refer to flue damper section
NO
Select model
631275
Refer to fan module section
621265 631265
Wiring loom open circuit. Check for breaks or damaged wiring
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Component Tests 1- 3 Test 1
Components will be "live". Personal Protective Equipment should be worn when conducting these tests.
Using a multimeter set on the AC volts scale, measure between active and neutral and active and earth on the terminal block. Normal voltage is AC240 volts. If either test fails a polarity or wiring problem exists.
Test 2
Components will be "live". Personal Protective Equipment should be worn when conducting these tests.
Using a multimeter set on the AC volts scale, unplug the 3-pin plug from the GPO and measure between the active and neutral pins and between the active and earth pins of the GPO. Normal voltage is AC240 volts. If either test fails a polarity or wiring problem exists. Test 3
Components will be "live". Personal Protective Equipment should be worn when conducting this test.
Note: On outdoor models the rain shield should be removed while conducting this test. Using a multimeter set on the AC volts scale, measure between terminal 1 (orange wire) and terminal 4 (blue wire) at the thermostat. Normal voltage when thermostat contacts are closed is AC240 volts
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Component Tests 4 - 6 Test 4
Hot water capable of scalding may discharge from the T&PR valve drain. Personal Protective Clothing should be worn when conducting this test.
60
Press the down button on the thermostat for 5 seconds the current `set point' temperature will be displayed. Using a thermometer measure the water temperature at the T&PR valve drain. If the measured temperature is equal to or greater than the set point there will not be a call for heat Test 5
Components will be "live". Personal Protective Equipment should be worn when conducting this test.
Using a multimeter set on the AC volts scale, measure between the orange wire ("LINE") and the blue wire ("LINE COM") on the ignition module. Normal voltage is AC240 volts.
Test 6
240
Components will be "live". Personal Protective Equipment should be worn when conducting this test.
NOTE: The thermostat must be calling for heat and the flue or mechanical ventilation fan operating to conduct this test. (Refer to test 3) Using a multimeter set on the AC volts scale, measure between the switch wire from the pressure or sail switch and neutral on the terminal block Normal voltage is AC240 volts.
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Fault Finding - Chart 2
1
Disconnect power and test ECO
Test 7 Is the ECO open circuit? YES Reset the ECO and restore power
NO
Restore Power
Test 8 Is the thermostat display still blank? YES Is there power at the thermostat? YES Replace thermostat
NO Check the set temperature 2.1
Wiring loom open circuit. Locate break and repair
Test 4
Is the set temperature 82 degrees?
YES
Is a circulator fitted? YES
NO
Advise customer to have a circulator fitted
NO
Is the circulator operating? YES
NO
Replace circulator
Check the thermostat offset and differential settings Refer to Thermostat section Are the settings correct? YES
NO
Reprogram the thermostat correctly
Does the display show AH 88 or E1?
YES
NO Test 9 Is the resistance of the sensors correct? NO Replace temperature sensor set
YES
Does the displayed temperature and the water temperature match?
NO
Adjust offset (CO) parameter so water temperature and thermostat match. Refer to Thermostat section
YES
5
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Component Tests 7- 9 Test 7
Ensure power is isolated prior to conducting this test.
Using a multimeter set on the x1 scale, measure across the terminals of the over temperature cut out. Normal resistance should be less than 1 ohm.
Test 8
Components will be "live". Personal Protective Equipment should be worn when conducting this test.
Using a multimeter set on the AC volts scale, measure between terminal 2 (red wire) and terminal 4 (blue wire) and terminal 3 (red wire) and terminal 4 (blue wire) of the thermostat. Normal voltage for both tests is AC240 volts. Indoor model shown Test 9
60
Ensure power is isolated prior to conducting this test.
Remove the hot and cold sensors from the probes and using a thermometer measure and note the temperature inside each probe. Using the table and formula on page 29 calculate the resistance. Reinsert the hot and cold sensors into the probes, wait 2 minutes then unplug the sensor set from the thermostat and using a multimeter set on x1000 resistance scale measure the resistance of the sensor set. The measured value should be within 5% of the calculated value.
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Electronic Thermostat The electronic thermostat has several parameters that control the water heater operation. Under normal conditions, including a power outage, these settings do not require adjustment, however following a thermostat replacement or if the delivered water temperature deviates significantly from that displayed on the thermostat, the settings should be checked and may require adjustment. Thermostat Parameters Parameter Description Range MIN MAX
C0
Temperature Probe Calibration (Offset) Temperature increase or decrease added to the temperature -20ºC +20ºC detected (displayed) to adjust the temperature probe to the actual value. Differential Temperature decrease from the thermostat "set point" required before the thermostat contacts close to initiate the heating cycle. Maximum "Set Point" Limiter The "set point" cannot be adjusted above this value, with the "AH" (alarm high) temperature alarm activated if the detected temperature rises above this value. 1ºC 20ºC
C1
C2
xxºC
82ºC
C3
Minimum "Set Point" Limiter The "set point" cannot be adjusted below this value, with the -50ºC "AL" (alarm low) temperature alarm activated if the detected temperature falls below this value. Type of operation (Heat/Cool) Selects the thermostat operation for cooling or heating applications 0 = Cooling (Differential above the "set point") 1 = Heating (Differential below the "set point") Block Programmed Parameters Prevents parameters from being altered 0 = No (Parameters can be altered) 1 = Yes (Parameters cannot be altered) Exit Programming Locks in changes made to parameters.
xxºC
P0
0
1
P2
0
1
EP
-
-
The electronic thermostat features several other parameters that are not utilized by the heavy-duty gas models; these must not be altered from the existing settings.
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Electronic Thermostat Diagnosis In the event a fault occurs either internally or externally a 2-digit code will be displayed on the thermostat LED to indicate the fault. Code AL Possible Cause Ignition module in "wait" or "lock out" mode Temperature below the minimum set Gas supply failure point parameter C3 Ancillary equipment failure i.e. power flue Burner not shutting down Temperature above the maximum Stacking set point parameter C2 Thermostat incorrectly programmed Circulator not fitted for 82º setting Memory error Temperature sensor set open circuit Replace thermostat Replace sensor set Fault
AH EE E1
Electronic Thermostat Adjustment Thermostat Parameters The table below details the parameter settings for the thermostat set point. These parameters MUST be set correctly for the water heater to operate properly. Temperature "Set Point" 60 - 64 65 - 69 70 - 74 75 - 79 80 - 81 82
(Recirculation required)
(C0) 14 15 16 17 18 18
(C1) 2 2 2 2 2 2
Parameter (C2) 80 80 80 85 85 85
(C3) 55 60 65 70 75 75
(P0) 1 1 1 1 1 1
Note: During the programming process if a button is not pressed for 25 seconds or the programme is not exited via the EP parameter the thermostat will revert to the temperature display without modifying the program. It will be necessary to reprogram the thermostat again should this occur. Adjusting the Water Temperature When adjusting the thermostat setting (`set point') it will also be necessary to alter the offset. The table opposite outlines the thermostat temperature and the corresponding offset. Failure to adjust the offset will result in incorrect outlet water temperature. Temperature ºC 60 64 65 69 70 74 75 79 80 81 82
(Recirculation required)
Offset (C0) 14 15 16 17 18 18
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To adjust the thermostat setting and offset 1. Press the "down" button for 5 seconds. The current set point temperature will be displayed. Release the button. 2. Press the "down" button to decrease the set point or the "up" button to increase the set point. 3. Once the required temperature is selected, press and hold the "down" button and the "up" button simultaneously. The display will revert to the current water temperature in the water heater. 4. Press and hold the "down" button and the "up" button simultaneously for 10 seconds, "C0" (offset program) will be displayed. Release the buttons. 5. Press and hold the "down" button and the "up" button simultaneously again. The current setting for "C0" will be displayed. Release the buttons. 6. Press the "down" button to decrease the setting or the "up" button to increase the setting according to the table above i.e. if the temperature set in step three is 60 then the offset value must be 14 (refer to table on page 25). 7. Once the required offset is selected press and hold the "down" button and the "up" button simultaneously, "C0" will be displayed. 8. Press the "down" button once; "EP" (exit program) will be displayed. 9. Press and hold the "down" button and the "up" button simultaneously; the current water temperature in the water heater will now be displayed and programming complete. To adjust the differential 1. Press and hold the "down" button and the "up" button simultaneously for 10 seconds, "C0" (offset program) will be displayed. Release the buttons. 2. Press the "up button once, "C1" is displayed. 3. Press and hold the "down" button and the "up" button simultaneously again. The current setting for "C1" will be displayed. Release the buttons. 4. Press the "down" button to decrease the setting or the "up" button to increase the setting according to the table on page 25 i.e. for a set temperature of 60 then the differential value is 2. 5. Once the required differential is selected press and hold the "down" button and the "up" button simultaneously, "C1" will be displayed. 6. Press the "down" button twice; "EP" (exit program) will be displayed. 7. Press and hold the "down" button and the "up" button simultaneously; the current water temperature in the water heater will now be displayed and programming complete.
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To adjust the maximum set point 1. Press and hold the "down" button and the "up" button simultaneously for 10 seconds, "C0" (offset program) will be displayed. Release the buttons. 2. Press the "up button until "C2" is displayed. 3. Press and hold the "down" button and the "up" button simultaneously again. The current setting for "C2" will be displayed. Release the buttons. 4. Press the "down" button to decrease the setting or the "up" button to increase the setting according to the table on page 25 i.e. for a set temperature of 60 then the maximum set point value is 80. 5. Once the required maximum set point is selected press and hold the "down" button and the "up" button simultaneously, "C2" will be displayed. 6. Press the "down" button until "EP" (exit program) is displayed. 7. Press and hold the "down" button and the "up" button simultaneously; the current water temperature in the water heater will now be displayed and programming complete. To adjust the "minimum set point" 1. Press and hold the "down" button and the "up" button simultaneously for 10 seconds, "C0" (offset program) will be displayed. Release the buttons. 2. Press the "up button until "C3" is displayed. 3. Press and hold the "down" button and the "up" button simultaneously again. The current setting for "C3" will be displayed. Release the buttons. 4. Press the "down" button to decrease the setting or the "up" button to increase the setting according to the table on page 25, i.e. for a set temperature of 60 then the minimum set point value is 55. 5. Once the required minimum set point is selected press and hold the "down" button and the "up" button simultaneously, "C3" will be displayed. 6. Press the "down" button until "EP" (exit program) is displayed. 7. Press and hold the "down" button and the "up" button simultaneously; the current water temperature in the water heater will now be displayed and programming complete. To adjust the "type of operation" 1. Press and hold the "down" button and the "up" button simultaneously for 10 seconds, "C0" (offset program) will be displayed. Release the buttons. 2. Press the "up button until "P0" is displayed. 3. Press and hold the "down" button and the "up" button simultaneously again. The current setting for "P0" will be displayed. Release the buttons. 4. Press the "down" button or the "up" button to change the setting. The type of operation must be set to 1. 5. Press and hold the "down" button and the "up" button simultaneously, "P0" will be displayed. 6. Press the "down" button until "EP" (exit program) is displayed. 7. Press and hold the "down" button and the "up" button simultaneously; the current water temperature in the water heater will now be displayed and programming complete.
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To unblock parameters 1. Press and hold the "down" button and the "up" button simultaneously for 10 seconds, "C0" (offset program) will be displayed. Release the buttons. 2. Press the "up button until "P2" is displayed. 3. Press and hold the "down" button and the "up" button simultaneously again. The current setting for "P2" will be displayed. Release the buttons. 4. Press the "down" button or the "up" button to change the setting. In order to be able to adjust parameters "P2" must be set to 0. 5. Press and hold the "down" button and the "up" button simultaneously, "P2" will be displayed. 6. Press the "down" button until "EP" (exit program) is displayed. 7. Press and hold the "down" button and the "up" button simultaneously; the current water temperature in the water heater will now be displayed and programming complete. Temperature variation In some cases the actual water temperature may vary from that displayed on the thermostat despite the parameters being correctly programmed. This is most likely to occur in recirculated systems. In order to check the actual tank water temperature, the measurement: 1. Must be taken at the T & PR valve drain line. 2. The burner must be off for at least 5 minutes before the temperature measurement is taken. 3. Water should not be drawn from the system. If the temperature deviates from that displayed on the thermostat by more than 2 degrees it will be necessary to custom set the offset parameter. When reprogramming the offset parameter (C0) it will be necessary to take into account the current "offset" already programmed into the thermostat. For example if the current "set point" is 70 then the offset should currently be set at 16. If the displayed temperature is 70ºC but the actual measured water temperature is 75ºC then the offset will need to be increased by 5 (the difference between the displayed temperature and the measured temperature) from 16 to 21, not set at 5. The same principal applies if the thermostat is reading high. Using the example above if the measured water temperature was 65ºC then the offset will need to be decreased by 5 (the difference between the displayed temperature and the measured temperature) from 16 to 11, not set at 5. NOTE: Where the displayed water temperature is 10 or more degrees BELOW the measured water temperature and the thermostat offset is programmed correctly for the set point, conduct a sensor resistance test (refer to test 9). If the sensor set is faulty do NOT attempt to overcome the difference by adjusting the thermostat offset, replace the sensor set.
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Temperature Sensor Set The temperature sensor set consists of 2 NTC (negative temperature coefficient) thermistors, which form the hot and cold sensors. In order to achieve the average water temperature in the cylinder the cold sensor has an additional resistor connected in parallel to it (refer to the circuit diagram opposite), this resistor is mounted on a small circuit board insulated into the sensor wiring loom. It is critical that the cold sensor (designated by BLUE heat shrink on the wiring) is always installed in the lower sensor pocket and the hot sensor (designated by RED heat shrink on the wiring) is always mounted in the top sensor pocket. Failure to do so will cause the heater to malfunction. Sensor Resistance
Molex Plug PCB BIAS Resistor (2700 ohms)
Hot Sensor
In order to calculate the overall resistance of the sensor set it will be necessary to measure the temperature in the hot and cold sensor probes using a thermometer and then using the table opposite (applies to both sensors) and formula below, calculate the resistance. Sensor set resistance =
ºC 0 5 10 15 20 25 30 + R2
Ohms 27280 22050 17960 14680 12090 10000 8313
ºC 35 40 45 50 55 60 65
Ohms 6941 5828 4912 4161 3537 3021 2589
ºC 70 75 80 85 90 95 100
Ohms 2229 1924 1669 1451 1266 1108 973
( R1 + R3 )
R1 x R3
Where: R1 = cold sensor resistance, R2 = hot sensor resistance & R3 = Bias resistor (2700 ohms) Example: The measured temperature of the cold sensor pocket is 60 degrees and the hot sensor pocket is 70 degrees. From the table above the resistances for each sensor are 3021 ohms and 2229 ohms respectively, therefore Sensor set resistance = Sensor set resistance = Sensor set resistance = Sensor Fault Conditions Symptom Thermostat displays E1 Thermostat displays AH 88 Thermostat reads low Thermostat reads high Possible Cause Hot sensor open circuit Hot sensor short circuited Cold sensor open circuit Cold sensor short circuited Remedy Replace Sensor Set
( (
3021 x 2700 3021 + 2700 8156700 5721 1425.75
) )
+ 2229 + 2229 = 3654.75 ohms
+ 2229
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Cold Sensor
-t
-t
Fault Finding Chart 3
2
Is the thermostat displaying an error code?
NO Refer to Thermostat section Are the thermostat parameters set correctly? YES Test 4 Does the displayed temperature and the water temperature match? Is the reading UNDER by 10 or more degrees? Adjust offset (CO) parameter so water temperature and thermostat match. Refer to Thermostat section Replace sensor set Reprogram thermostat correctly and retest operation. Refer to Thermostat section
NO
YES
NO
NO
YES
YES
Replace thermostat
EE?
YES
Replace thermostat
NO Test 9 NO E1? YES Is the resistance of the sensors correct? YES NO Replace sensor set
NO
Replace thermostat
AL?
YES
Is the thermostat parameter C3 set correctly?
Refer to Thermostat section NO
Reprogram thermostat correctly and retest operation. Refer to Thermostat section Replace thermostat
NO
YES
Refer to Thermostat section AH? YES Is the thermostat parameter C2 set correctly? NO Reprogram thermostat correctly and retest operation. Refer to Thermostat section
YES Is the fault AH 88?
NO
Test 4 Does the displayed temperature and the water temperature match?
NO
Adjust offset (CO) parameter so water temperature and thermostat match. Refer to Thermostat section
YES
2.1
YES
Replace sensor set
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Ignition Module The ignition module continuously performs a self-check routine. Any time a fault is detected, internally or externally the module will enter either a "wait" mode or a "lock out" mode depending on the fault detected. An LED indicator light on the ignition module will emit a series of flashes to indicate the fault. The LED will flash on for approximately ¼ second and off for approximately ¼ second. A 2 second delay occurs between each group of flashes. The LED will stay on continuously for approximately 1 second when power is turned on. With the exception of ignition retry lockout (1 flash) the ignition module will automatically reset if the fault clears or is rectified (repaired). Ignition retry "lockout" requires a manual reset to be performed. Fault Codes Flashes 1 2* 3* 4 5 6 7 Fault Ignition retry lockout Pressure switch not open Pressure switch not closed Faulty igniter / igniter sensing circuit Flame detected with gas valve de-energised Reversed polarity Flame failure sense circuit Possible Cause Gas failure Low gas pressure Failed gas valve Faulty pressure switch Faulty fan Faulty pressure switch Faulty igniter Poor connection in multi-pin plug Power spike Failed ignition control module Failed gas valve Active and Neutral reversed AC leakage > than 6.5A High resistance to earth Moisture Low gas pressure Action Rectify fault and manually reset ignition module Auto reset when fault is rectified
* Fault code only available on ignition module 50A72-178 utilised in 631275 models manufactured after 09/02/05. Flashes Steady Fault Action Module failure or event counter limit Reset the module, if the LED remains exceeded steady replace module
· If the module resets the event counter has been exceeded indicating there is a fault with the heater or the installation i.e. low gas pressure. Flashes Rapid flash · Fault Frequency check failure Cause Poor supply frequency
Check for large contactors, relays or electronic speed controllers in the plant room.
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1 Flash (Retry lockout) - Chart 4 This fault occurs if flame is not sensed after the fourth ignition attempt and is most commonly caused by insufficient gas pressure.
Reset the ignition module and allow the heater to relight This procedure assumes there is power to the ignition module!
Does the igniter glow?
NO
Test 10 Is there an output from the ignition module? YES
NO
Replace the ignition module
YES
Replace the igniter assembly Check the `dynamic' inlet gas pressure. Refer to installer if low With all gas burning appliances lit the supply pressure to the heater must be at least 1.13 kPa (natural gas) or 2.75 kPa (Propane gas)
Did the burner light?
YES
Did the burner remain lit?
YES
NO Test 11 Is there flame current present? NO
Is the flame rod or wiring damaged or broken? NO
YES
Replace the igniter assembly or wiring
Replace the ignition module Check / reset burner pressure
NO
YES
Is the flame current correct?
YES
NO
Is the flame rod or wiring damaged or broken? NO
YES
Replace the igniter assembly or wiring
Check Burner Earth
Test 12 Is there voltage to the gas valve? YES
Test 13 Is the resistance of the gas valve correct?
NO
Test 14 Is the gas valve microtemp open circuit?
YES
Excessive heat roll out is occurring. Replace the gas valve and determine reason for roll out i.e. poor fluing
NO YES Test 14A Is the door switch open circuit?
NO
Replace the gas valve (Solenoid failure) Replace gas valve (Mechanical Failure)
Is the model a 631275?
YES
YES
Replace door switch
NO NO
Replace the ignition module
NOTE: Micro-temp failure is due to excessive heat roll out from the combustion chamber. Common causes are blocked or restricted primary flue, undersized, blocked or restricted secondary fluing or a flue cowl terminating in a pressurized zone (refer to page 56).
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Component Tests 10 - 12 Test 10
Components will be "live". Personal Protective Equipment should be worn we conducting these tests.
During the ignition trial period using a multimeter set on the AC volts scale, measure between the orange wire ("IGN") and the red wire ("IGN COM") terminals on the ignition module. The voltage should be between AC140 and 200 volts.
Test 11
Components will be "live". Personal Protective Equipment should be worn we conducting these tests.
The use of flame current test loom part number 890284 will assist in conducting this test. 1. Using a multimeter set on the AC microamps scale and wired in series with the flame rod circuit, measure the flame current. A current up to but not exceeding AC10 micro-amps may be detected while flame is established. 2. Set the multimeter to the DC micro-amps scale. A current of approx. DC4.5 micro-amps should be detected while flame is established. Test 12
Components will be "live". Personal Protective Equipment should be worn when conducting this test.
Using a multimeter set on the AC volts scale, measure between the brown wire ("MV") and the blue wire ("MV COM") on the ignition module while the heater is attempting to light. Normal voltage from the ignition module is AC240 volts.
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Component Tests 13 14A Test 13
Isolate power before conducting this test.
Using a multimeter set on the x20K resistance scale, measure across the gas valve terminals. Normal resistance should be approximately 2.3 kilo-ohms. A reading of approx 3.1 kilo-ohms indicates the internal solenoid has failed. A reading of approx. 8.7 kilo-ohms indicates the external solenoid has failed Test 14
Isolate power before conducting this test.
Note: It will be necessary to strip a small portion of the heat shrink off the gas valve wiring to access the micro-temp. Using a multimeter set on x1 resistance scale, measure across the micro-temp fitted in the gas valve wiring. Normal resistance should be less than 1 ohm. Test 14A
Isolate power before conducting this test.
Using a multimeter set on the x1 resistance scale, measure across the door switch terminals. Normal resistance with the striker depressed should be less than 1 ohm.
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4 Flashes (Faulty igniter / Igniter sensing circuit) - Chart 5
Isolate power to the heater and disconnect the multi-pin plug from the ignition module Test 15 Is the resistance of the igniter correct? YES Replace ignition module
Disconnect the igniter wiring from the wiring loom at the 3 pin plug
Test 16 Is the resistance of the igniter correct? YES
NO
Replace the igniter assembly
Replace the wiring loom
Compo