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Manual 2100-769A
Page
32 of 50
compressor could stop due to the high pressure control
opening because of high pressure condition created
by operating in the cooling mode with outdoor fan off.
Pressure will rise rapidly as there is likely no actual
frost on the outdoor coil in this artificial test condition.
There is also a 5-minute compressor time delay
function built into the Heat Pump Control to protect
the compressor from short cycling conditions. The
board’s LED will have a fast blink rate when in the
compressor time delay. In some instances, it is helpful
to the service technician to override or speed up this
timing period and shorting out the
SPEEDUP
terminals
for a few seconds can do this.
Low Pressure Switch Bypass Operation
The control has a selectable (SW1) low pressure switch
bypass set up to ignore the low pressure switch input
during the first (30, 60, 120 or 180 seconds) of “Y1”
signal from thermostat.
After this period expires, the control will then monitor
the low pressure switch input normally to make sure
that the switch is closed during “Y” operation (defrost
control board).
FIGURE 22
Defrost Control Board
120*
SW
1
SW
2 TIME (SEC)
OFF
OFF
ON
ON
OFF
ON
OFF
ON
30
60
180
MIS-2668 A
OFF
LOW PRESSURE BYPASS TIMER SWITCH
*(FACTORY SETTING 120 SECONDS)
ACCUMULATED DEFROST TIME TIMER
(FACTORY SETTING 60 MIN.)
ON
Model
Setting
C36HY
60
C42HY
60
C48HY
60
C60HY
60