Defrost Systems (Described And Explained) - Aquacal 100 Owner's Manual And Installation Manual

Controls Configuration & Adjustments...
DEFROST CYCLE (HEAT ONLY UNITS):
The microprocessor controller monitors the heater's air-coil temperature, minimizing air-coil freeze-
up during cooler weather conditions. If the controller senses air-coil temperatures conductive to
making ice, the heater's compressor operation is interrupted while the fan is allowed to continue in
operation.
With the compressor off, the air-coil begins to warm to the surrounding air temperature. When air-
coil temperatures rise above approximately 38
In the event air temperatures remain below approximately 38
the air temperature rises above 38
remains off.
During defrost cycles, when the controller has stopped compressor operation, the display will read:
[FS].
DEFROST CYCLE (HEAT & COOL UNITS):
The microprocessor controller, in conjunction with the defrost sensor, constantly monitors the
heater's evaporator (air-coil) temperature. Should the controller sense ice or frost has formed on
the evaporator, sufficient in amount as to affect the heater's performance, an active defrost cycle
(more below) is initiated. Before initiating a defrost command, the controller defrost logic looks at
both the air-coil temperature, and the length of time the coil has remained at an ice-making
temperature.
Active defrost involves using hot refrigerant gas, from the compressor, to rapidly remove ice or frost
from the evaporator coil. In practice, during a hot gas defrost cycle, valving, internal within the
refrigerant system, reverses the flow of the refrigerant; this reversal of flow temporarily makes the
air-coil the condenser. During hot gas defrost, the air-coil warms very quickly, and accumulated ice
and frost is rapidly melted. Under most conditions, the evaporator will be completely cleared in
under 5-minutes.
HEAT & COOL DEFROST SEQUENCE DETAILS:
•
When the controller senses air-coil temperatures conductive to making ice, the unit will enter a
50-minute defrost delay (counting) period.
•
During the counting period, the fan and compressor will continue to operate, and the water will
continue to be heated. During the counting period, it is normal to see a moderate amount of frost
and ice formation on the air coil.
•
If, after the 50-minute counting period, the controller senses a need to defrost:
1. The refrigerant circuit reversing valve will be activated, changing the flow of hot refrigerant
gas from the pool water heat exchanger to the air-coil.
2. Fan operation will be suspended, permitting maximum heating of the air-coil.
3. The reverse cycle will continue until either:
A. The air-coil attains a predetermined temperature (indicative of total defrost), or;
B. Until 5-minutes has elapsed (regardless of total defrost having occurred).
•
During hot gas defrost cycles, the compressor will not deactivate; rather, the compressor will
continue operation throughout the sequence. Upon completion of the defrost cycle (as
terminated per "A" or "B," above), the reversing valve will be deactivated, fan operation will
recommence, and water heating will resume.
Defrost Systems- Described
o
F, the compressor is restarted and heating resumes.
o F. The unit will not heat the pool water as long as the compressor
o
F, the compressor will remain off until
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