Rheem W2W Series, Owner'S Manual And Installation Instructions

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8
HOW YOUR WATER HEATER WORKS
The Rheem commercial water to water heat pump is an instantaneous type and
does not have an integral storage cylinder. The unit is designed to be installed
indoors or
outdoors. The water heater’s evaporator absorbs heat from the
returning chilled water circuit or condenser loop and transfers this heat into the
potable water. A circulator transfers
the heated water to a bank of storage
tanks. By taking heat from the chilled
water circuit, the heat pump reduces
load on chiller as colder water returns
to the building chiller circuit. The heat
pump produces a sound level of up to
59 dBA (measured at 3 metres) when
it is operating.
When hot water is drawn off and cold water enters the storage tanks, a remote
thermostat activates the compressor and circulating pumps of the water heater.
The chiller return water (building heat) is drawn in through the cold side inlet and
then through the evaporator (single wall heat exchanger), where heat is
transferred to a refrigerant fluid. The fluid is compressed and passes to the
condenser (double wall heat exchanger) where heat is transferred into the
potable 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. This process continues until the water in the storage tanks
reaches the set temperature.
The heat pump is designed to operate most efficiently at cold side temperatures
between a minimum of 12

C and maximum of 35
°
C. Operation with higher cold
side inlet temperature is possible, however must be engineered in consultation
with Rheem. The efficiency of the water heater is relative to the building chilled
water circuit temperature and the incoming hot side (potable) water temperature.
Automatic safety controls are fitted to the water heater to provide safe and
efficient operation.
FREEZE PROTECTION
Ice may begin to form in the evaporator when the cold side outlet temperature
falls below 4
°
C or the flow rate of cold side water is excessively low or the pump
on the cold side fails, and this may damage the evaporator heat exchanger.