Rheem Thermal Manual
water to water Hot water
6
04/02/2021
Electrical
All electrical work must be carried out by licensed electricians and all the wiring should be carried
out to AS/NZS3000 latest edition wiring standards.
Refer to the internal electrical wiring diagram supplied with the units before proceeding with electrical
work. As a minimum, cable and fuse sizing must be correct relative to the unit’s specified
requirements. Rheem Thermal’s technical specification for each model nominates electrical demand
information and minimum circuit size.
For models up to 80 kW an isolating switch must be fitted adjacent to the Heat Pump, models above
100 kW have a factory installed isolation switch on the electrical panel.
To install the unit, remove the electrical service panel. No conduit entry points are provided, the
installer has to drill an appropriate hole in the desired location. Earth and Neutral wires need to be
connected to the appropriate terminal. Line voltage to terminals L1 and L2 and L3 if unit is three
phase. Every three phase unit comes with Phase sequencing relay therefore ensure connect correct
phase connections during commissioning.
Control Design
All Rheem Thermal heat pumps intended for individual installation are manufactured with in-built
thermostat control and refrigeration pressure safety controls.
Typically, the thermostat is mounted on the outside panel and displays entering water temperature
and/or leaving water temperature, with the sensor being located in a well to the inlet water and/or
outlet water pipe inside the unit. 6 meter tank sensor may have provided out side of the unit.
For systems comprised of multiple Heat pump units, the thermostat sensor and well may be provided
as follows depending on client requirement:
Provided loose to allow installation of thermostat controller display in heat pump control panel
(located separately to the heat pumps) with probe installed in the hot water storage tank.
The thermostat sensor is the controlling device in the heating system. This determines whether the
heat pump unit should run and is activated in response to the parameters set for temperature control.
That is, the heat pump will run when the entering water temperature (EWT) or tank temperature is less
than the desired set point (normally with a 3
K split) and stop running when the EWT is a set point.
The heat pump will likewise not run without water flow so there is a very direct link between the heat
pump, hot water recirculating pump and thermostat controller.
The thermostat sensor can be located in the hot water tank with control wiring back to the water
recirculating pump. The operation of the recirculating pump will be controlled by tank temperature,
with water flow to the heat pump activating its operation. This approach reduces recirculating pump
and heat pump run-hours and duty. Contact manufacturer at time of ordered to discuss wiring
requirements.
There is also a safety feature fitted to the evaporator side of all AWW and RTWW units this is to
prevent the water dropping below 5°C. This is to prevent possible freezing in the heat exchanger. If
the water temperature drops below 5°C the Anti-freeze cut out will cut the whole system down. In the
case of multiple stage units (2 or more compressors) there is Anti-freeze safety feature fitted to each
evaporator. If any of these sense below 5°C the system will be shut down until the temperature rises
again.
