Specifications
TM040 16, 18 & 20L Continuous Flow Gas Water Heater Service Instructions
D.O.I: 2/06/2009
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53
Heat Exchanger Replacement
1. Remove the Heat Exchanger. Refer „Heat Exchanger Removal‟ procedure on page 52.
2. Remove the Heat Exchanger Thermistor, Anti-Frost Heaters, Fan Assembly and Fan
Cowling from the old Heat Exchanger and refit to the replacement Heat Exchanger.
3. Check the Over Heat Limiter. Replace if damaged or open circuit.
4. Reassemble in reverse order of above.
5. Test for gas leaks using soapy water solution
6. Check for water leaks.
7. Check and if necessary adjust the MIN and MAX burner gas pressures. Refer to
„Burner Gas Pressure Check‟ procedure on page 46 and „Burner Gas Pressure
Adjustment‟ procedure on page 47.
Flow Sensor
1. Isolate cold water supply.
2. Remove the Front Panel. Refer to „Front Panel‟ procedure on page 48.
3. Disconnect the Flow Sensor multi-pin wiring plug at the PCB.
4. Remove two screws retaining the Flow Sensor at the base of the Water Body
Assembly.
5. Remove the Flow Sensor (Note: water may escape during this procedure).
6. Reassemble in reverse order of above.
Bypass Solenoid
The Bypass Solenoid is only available as part of the Water Body Assembly. Refer to
„Water Body Assembly‟ procedure on page 50.
Thermistors
1. Isolate cold water supply.
2. Remove the Front Panel. Refer to „Front Panel‟ procedure on page 48.
3. Relieve water pressure through a hot tap.
4. Locate the Thermistor requiring replacement. Note: The PCB will need to be removed
to gain access to the Hot Outlet Thermistor. Refer to PCB Assembly procedure on page
48.
5. Disconnect the relevant multi-pin plug from the PCB. Note: Some wiring retainers will
need to be released to allow wiring to be removed.
6. Remove the retaining screws and withdraw the Thermistor taking care not to damage
the o-ring (Note: with the exception of the Ambient Air Thermistor, water may escape
during this procedure).
7. Reassemble in reverse order of above.