Manual 2100-604A
Page
18 of 28
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
MIS-2668A
FIGURE 8
Defrost Control Board
Pressure will rise fairly fast 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 HPC. This is 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 “Y” operation.
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.
High Pressure Switch Operation
- The control has a
built-in lockout system that allows the unit to have the
high pressure switch trip up to two times in 1 hour and
only encounter a “soft” lockout. A “soft” lockout shuts
the compressor off and waits for the pressure switch to
reset, which at that point then allows the compressor
to be restarted as long as the 5-minute short cycle
timer has run out. If the high pressure switch trips a
third time within one hour, the unit is in “hard” lockout
indicating something is certainly wrong and it will not
restart itself.
