Specifications
TM040 16, 18 & 20L Continuous Flow Gas Water Heater Service Instructions
D.O.I: 2/06/2009
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9
Sequence of Operation Component Diagram
1)
Hot Water Tap
2)
Water Flow Servo Motor
3)
Water Flow Sensor
4)
Inlet Water Temperature Thermistor
5)
Combustion Chamber Thermistor
6)
Outlet Water Temperature Thermistor
7)
PCB
8)
Water Filter (Strainer)
9)
Gas Inlet Solenoid Valve
10)
Gas Solenoid Valve 1
11)
Gas Solenoid Valve 2
12)
Proportional Gas Solenoid Valve
13)
Nozzle
14)
Burner
15)
Igniter
16)
Igniter Electrode
17)
Flame Sensor
18)
Heat Exchanger
19)
Over Temperature Limiter
20)
Exhaust (Flue) Outlet
21)
Combustion Chamber
22)
Anti Frost Heater
23)
Fan
24)
Fan Motor
25)
Drain Plug With Relief Valve.
26)
Controller (Optional)
Bypass Operation
The bypass is a section of copper pipe work connected between the water body assembly
(effectively the cold water inlet) and the outlet of the heat exchanger and allows a quantity
of cold water to bypass the heat exchanger. The purpose of the bypass is to ensure the
heat exchanger operates at temperatures above the dew point of the combustion gases,
ensuring condensate is not produced, but low enough to maximise the heat exchangers
life. A solenoid valve fitted to the water body assembly controls the bypass. The PCB
activates the solenoid based on heat exchanger temperature and selected outlet water
temperature.
Anti-Frost Heater Circuit
All models have an anti frost heater circuit. The anti-frost heaters are wired in series and
operate independently from the water heater.
A thermostat sensing ambient air temperature, positioned in the wiring loom near the
bottom of the water heater, activates the anti-frost heaters when the ambient air
temperature falls to 4ºC +4ºC/-2ºC and deactivates the anti-frost heaters when the
temperature rises above 12ºC.
In the event a heater block becomes open circuit the total heater circuit is rendered
inoperable. The circuit is split into two sections with 4 heaters in total.
Refer to „Anti-Frost Heaters‟ on page 52 for replacement procedure.