Pentair ThermalFlo, User Manual, Page: 31 / 40

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ThermalFlo Installation and User’s Guide
Professional Maintenance and Service
The Pentair ThermalFlo Heat Pump is one of the most efficient ways to heat a pool or spa. The heat pump
transfers heat from the outside air to the pool or spa water by means of an internal heat exchanger.
When the fan is turned on, warm air is drawn through the R410A refrigerant charged air coil, turning the cold
liquid refrigerant to a warm gas. The gas then flows through the reciprocating compressor, which increases the
pressure and refrigerant temperature. The hot refrigerant gas enters the water to gas heat exchanger where the
water is heated and returned to the pool. During this heat exchange process the refrigerant is cooled and
returned to the air coil and the cycle repeats.
NOTE: The maximum heat output and efficiency of a heat pump is dependent upon the quality and performance
of the major components used. As equally important are the environmental conditions (for example, air
temperature, humidity, water temperature, and wind).
WARM
AIR IN
COLD
AIR OUT
FAN
EVAPORATOR
COIL
WATER
OUTLET
(Warm)
WATER
INLET
(Cold)
Figure 16. Typical Heating Cycle