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The solenoid operated bypass comprises a valve (located in the water body assembly)
that is controlled by a solenoid (mounted on the water body assembly). The PCB activates
the solenoid at the following predetermined temperatures:
Without Touch Pads: When the unit is preset at 40 or 43 degrees.
With Touch Pads: When temperatures from 37 to 46 degrees are selected.
At all other times the bypass does not operate.
Anti-Frost Heater Circuit
Models with an 'F' in the model number have an anti frost heater circuit e.g. 871020NF-B.
The anti-frost heaters are wired in series and operate independently from the water heater.
18 and 20 litre models have a 58-watt anti-frost system.
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 total heater circuit measures 993.2 ohms.
The circuit is split into two sections with 4 heaters in total. To determine which section has
failed, isolate the power to the water heater and unplug the wiring connectors at the
thermostat, cord set and the water body assembly heater block. The heat exchanger and
hot water outlet heater's resistance (3 heater blocks) is 719.2 ohms. The resistance of the
water body assembly heater is 274 ohms. Refer to Procedure 10 on page 51 for
replacement procedure.
Product Changes
Software Changes
Models manufactured after July 2006 have a change to the software which controls the
operation of the heater. When an inlet water temperature of more than 58ºC and more
than the set point temperature minus 2ºC is detected by the inlet water temperature
thermistor, the fan and burner will not operate.
This function has been introduced to enhance the operation of the water heater and
remove the need for a Solar Bypass Valve when the Integrity 20 is connected as an in-
series gas booster to a solar water heating system (for more information refer to 'In-series
Gas Boosting' on page 11). Note: 875 series models and 18 Litre Integrity's are not
suitable for use as in-series gas boosters.
Models with the revised software have a -B suffix added to the model number i.e.
871020NF-B.
TM002 Integrity 18 & 20L Service Instructions REV: E
10
D.O.I: 7/11/2007
This document is stored and maintained electronically by
Service. All printed copies not bearing this statement in RED are deemed "uncontrolled"
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