Manual 2100-654C
Page
22 of 34
activate the timing circuit. This permits the defrost
cycle to be checked out in warmer weather conditions
without the outdoor temperature having to fall into the
defrost region.
In order to terminate the defrost test, the
SEN JMP
jumper must be removed. If left in place too long, the
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 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 1 hour,
the unit is in “hard” lockout indicating something is
certainly wrong and it will not restart itself.
