13
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
Содержание 551A
Страница 14: ...14 TYPICAL WIRING SCHEMATIC Single Fan Units Sizes 036 073 ...
Страница 16: ...16 TYPICAL WIRING SCHEMATIC Sizes 155 300 ...
Страница 29: ...29 BASE UNIT DIMENSIONS 558F036 072 0TFQ004 012 558F036 150 ...
Страница 30: ...30 BASE UNIT DIMENSIONS 558F073 0TFQ004 012 558F036 150 ...
Страница 31: ...31 BASE UNIT DIMENSIONS 558F090 102 120 150 0TFQ004 012 558F036 150 ...
Страница 32: ...32 BASE UNIT DIMENSIONS 558F091 121 0TFQ004 012 558F036 150 ...
Страница 74: ...74 BASE UNIT DIMENSIONS 551B036 072 0TFQ004 012 551B036 150 ...
Страница 75: ...75 BASE UNIT DIMENSIONS 551B090 150 0TFQ004 012 551B036 150 ...
Страница 133: ...133 BASE UNIT DIMENSIONS 558F180 210 0TFQ004 012 558F180 300 ...
Страница 134: ...134 BASE UNIT DIMENSIONS 558F240 0TFQ004 012 558F180 300 ...
Страница 135: ...135 BASE UNIT DIMENSIONS 558F300 0TFQ004 012 558F180 300 ...
Страница 153: ...153 BASE UNIT DIMENSIONS 551A155 180 0TFQ004 012 551A155 180 ...