Anti-Frost Heater Circuit; In-Series Gas Boosting - Rheem II Series Service Instructions Manual

ANTI-FROST HEATER CIRCUIT

The 5 anti-frost heaters are wired in series and are controlled by the ambient air sensor and
the PCB. All models have a 68-watt anti-frost system.
A thermistor, 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 becoming open circuit the total heater circuit is rendered
inoperable. The total heater circuit measures 850 + 5% ohms.
Refer to Procedure 12 on page 56 for replacement procedure.

IN-SERIES GAS BOOSTING

Temperature controllers must not be fitted if this water heater is installed
as part of a solar water heater system because water at a temperature
much higher than the controller setting can be delivered.
Rheem 874 series & Solahart 60° models may be used as in-series booster water heaters
to a solar preheat water heater. When the inlet water temperature is 58°C or higher the fan
and burner will not operate despite water flowing through the heat exchanger. When the
inlet water temperature is less than or equal to 57°C the burner will fire and boost the outlet
temperature to the preset outlet temperature setting provided the flow rate is greater than 3
litres per minute.
In this application the preset outlet temperature setting of the heater must be set at 70C to
comply with the requirements of AS3498. Refer to page 9 for details on checking and
adjusting the preset outlet temperature.
In-series gas boosting Solar Loline Installation
TM090 12-26 Series II CFGWH Service Instructions
REV AB – Issued February 2019
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