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CONTROLS (cont)
As the refrigerant leaves the evaporator, the refrigerant passes
a subcooler control low-pressure switch (S-LPS1 for circuit 1 or
S-LPS2 for circuit 2) in the suction line. This low-pressure
switch will deactivate the Perfect Humidity™ package when the
suction pressure reaches 60 psig. The subcooler control low-
pressure switch is an added safety device to protect against
evaporator coil freeze-up during low ambient operation. The
subcooler control low-pressure will only deactivate the 3-way
liquid line solenoid valve in the Perfect Humidity circuit. The
compressors will continue to run as long as there is a call for
cooling, regardless of the position of the subcooler control low-
pressure switch. The 3-way solenoid valve and the Perfect
Humidity package will be reactivated only when the call for cool-
ing has been satisfied, the subcooler control low-pressure
switch has closed above 80 psig, and a new call for cooling
exists. The crankcase heaters on the scroll compressors
provide additional protection for the compressors due to the
additional refrigerant charge in the subcooler.
When the thermidistat is satisfied, the relay internal switch
opens, cutting power to and deenergizing the LLSVs. The
refrigerant is routed back through the evaporators and the
subcooler coils are removed from the refrigerant loops. When
the thermostat is satisfied, C1 and C2 are deenergized and
the compressors, IFM, and OFMs shut off. If the thermostat
fan selector switch is in the ON position, the IFM will run
continuously.
Perfect Humidity™ Dehumidification Option