Service Manual

Part Number: 000015430 Rev 02 5/20 175
HARVEST PRESSURE REGULATING (HPR) SYSTEM
REMOTE CONDENSER ONLY
GENERAL
The harvest pressure regulating (HPR) system includes:
• Harvest pressure regulating solenoid valve (HPR
solenoid). This is an electrically operated valve which
opens when energized, and closes when
de-energized. The HPR solenoid valve is wired in
parallel with the harvest valve.
• Harvest pressure regulating valve (HPR valve). This is a
pressure regulating valve which modulates open and
closed, based on the refrigerant pressure at the outlet
of the valve. The valve closes completely and stops
refrigerant flow when the pressure at the outlet rises
above the valve setting.
FREEZE CYCLE
The HPR system is not used during the freeze cycle.
The HPR solenoid is closed (de-energized), preventing
refrigerant flow into the HPR valve.
HARVEST CYCLE
During the harvest cycle, the check valve in the discharge
line prevents refrigerant in the remote condenser and
receiver from back feeding into the evaporator and
condensing to liquid.
The HPR solenoid is opened (energized) during the harvest
cycle, allowing refrigerant gas from the top of the receiver
to flow into the HPR valve. The HPR valve modulates open
and closed, raising the suction pressure high enough
to sustain heat for the harvest cycle, without allowing
refrigerant to condense to liquid in the evaporator.
In general, harvest cycle suction pressure rises, then
stabilizes. Exact pressures vary from model to model.
Refer to cycle time/24 hour ice production and operational
pressure charts.