How Your Water Heater Works - Rheem 953060DP Owner's Manual And Installation Instructions

HOW YOUR WATER HEATER WORKS

The Rheem commercial air to water heat pump is an instantaneous type and
does not have an integral storage cylinder. The unit is designed to be installed
outdoors, with adequate supply of fresh air. The water heater's evaporator
absorbs heat from the surrounding air and transfers this heat into the water. A
circulator transfers the heated water to a bank of storage tanks.
When hot water is drawn off and cold water enters the storage tanks, a remote
thermostat activates the fan, compressor and circulating pump of the water
heater. Air is drawn in through the inlet on the side of the water heater and then
past the evaporator, where heat is transferred from the air to a refrigerant fluid.
The fluid is compressed and passes to the condenser (heat exchanger) where
heat is transferred into the water. The pump circulates water from the bottom of
the storage tanks through the heat exchanger and the heated water is circulated
back into the storage tanks. The fan discharges the cooled air through the fan
grilles on the top of the water heater. This process continues until the water in
the storage tanks reaches the set temperature.
Even on cold days, heat is drawn from the surrounding air. The heat pump will
operate most efficiently at temperatures between a minimum of 0°C and
maximum of 45°C. The efficiency of the water heater is relative to the
surrounding air temperature and the incoming water temperature.
Automatic safety controls are fitted to the water heater to provide safe and
efficient operation.
AUXILIARY BOOST OPERATION
The water heater can control an auxiliary heating source if the ambient
o
temperature falls below 0 C or if 50% or more of the water heaters refrigeration
circuits are in fault mode.
OPERATION AT LOW AMBIENT TEMPERATURE
o
As the ambient temperature falls below 5 C, the controller will automatically set
back the target set point, measured at the bottom of the storage tank, relative to
the ambient temperature, to a value set as the minimum. The factory default
o o
minimum set back is 60 C which correlates to an ambient temperature of 0 C.
As the ambient temperature increases, the set point will increase accordingly
until the normal set point is achieved. It is important to note that the sizing of the
system ensures hot water is delivered to the building even though the bottom of
o
the tank may be at a lower set point, and heating to above 60 C is ensured every
day in accordance with AS3498.
Setting back the target set point allows the heat pump to operate reliably at lower
ambient temperatures.
16