Specifications

TM022 Raypak RHP 33 Pool and Spa Heat Pump Service Instructions REV C
D.O.I: 14/03/2006
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*Free Chlorine must not exceed 5ppm, however occasional chemical shock dosing of the
pool or spa water should not damage the heater providing that the water is balanced to the
above conditions.
Automatic chemical dosing devices and salt chlorinators are usually more efficient in
heated water. Unless controlled, they can lead to excessive chlorine levels that can
damage the pool / spa heater.
Excessive chemical content in a swimming pool or spa will damage the Heat
Pump. DO NOT skimmer feed chemicals.
Ensure chlorinators and chemical dosing units are installed AFTER the Heat
Pump.
Operation
Normal Operation
The RHP33 series Heat Pump pool and spa heaters utilise R22 refrigerant to transfer heat
from the atmosphere to the pool or spa water flowing through the Heat Pump.
When the pool pump operates the resulting water flow operates the Heat Pump flow switch
enabling operation of the system. When the thermostat contacts close the evaporator fan
motor commences operation followed by the compressor motor (The compressor motor
has a six minute time delay). The action of the compressor creates a pressure difference
that causes the refrigerant to circulate through the sealed refrigeration system.
The refrigerant enters the evaporator as a liquid, as heat is absorbed from the atmosphere
by the refrigerant it changes state, at low pressure, from a sub cooled liquid to a super
heated vapour or gas (evaporates). The vapour then enters the compressor and obtains
more heat, known as heat of compression, and passes into the spiral condenser (heat
exchanger) as a super heated vapour at high pressure.
As the refrigerant passes through the spiral condenser (heat exchanger) it gives off heat
which is absorbed by the water flowing through a separate chamber inside the heat
exchanger. As the refrigerant gives off heat it cools and changes state back into a liquid
(condenses). The refrigerant then enters the evaporator again and the cycle is repeated.
A metering device, called a TX or expansion valve, is positioned between the condenser
and evaporator to control, or meter the flow of refrigerant into the evaporator. The TX valve
senses the temperature of the suction line and automatically meters the flow of refrigerant
based on the detected temperature.
Defrost Operation
At low ambient air temperatures it is possible for the evaporator to freeze. At an evaporator
temperature of approximately 3ºC the defrost switch activates switching off the
compressor (no heating). The fan will continue to run allowing the evaporator to defrost.
Normal operation will resume when the evaporator temperature returns to approximately
5.5ºC.