Koolaire KDT0300A Technician's Handbook page 96

NOTE: A head pressure control valve that will not
bypass, will function properly with condenser air
temperatures of approximately 70°F (21°C) or above.
When the temperature drops below 70°F (21°C), the head
pressure control valve fails to bypass and the ice machine
malfunctions. Lower ambient conditions can be simulated
by rinsing the condenser with cool water during the freeze
cycle.
Condition
Discharge Pressure - High
Liquid Line Temperature
- Hot
Discharge Pressure - Low
Liquid Line Temperature
- Cold
Discharge Pressure - Low
Liquid Line Temperature
- Hot
96
Probable
Cause
Valve stuck in
bypass
Valve not
bypassing
Ice Machine
Low on Charge
Part Number STH063 9/17
Corrective
Measure
Replace valve
Replace valve
Refrigerant
Charge
Verification