Manitowoc Ice FLAKE/CHIPLET QF0400 - Manual (Page 117)

Section 6 Electrical System
Part No. 80-1214-3 6-55
HIGH PRESSURE CONTROL (HPCO)
Function
The high pressure control stops the ice machine if
subjected to excessive high-side pressure.
The HPCO control is normally closed, and opens on a
rise in discharge pressure.
Specifications
Cut-out:450 psig ±10
Cut-in:Automatic reset
(must be below 300 psig to reset).
Check Procedure
1. Set ICE/OFF/CLEAN switch to OFF.
2. Disconnect main power supply to the ice machine.
3. Connect manifold gauges to access valves.
4. Hook voltmeter in parallel across the HPCO, leaving
wires attached.
5. Reconnect main power supply to the ice machine.
6. Set ICE/OFF/CLEAN switch to ICE and block
condenser with cardboard or similar material.
7. No air flowing through the condenser will cause the
HPCO control to open because of excessive
pressure. Watch the pressure gauge and record the
cut-out pressure.
Replace the HPCO control if it:
• Will not reset (below 300 psig).
• Does not open at the specified cut-out point.
LOW PRESSURE CUT-OUT CONTROL (LPCO)
RFC2085/RFC2385 (QF2200/QF2300) ONLY
Function
Energizes and de-energizes the contactor coil when suction
pressure rises above or falls below setpoint.
The LPCO control is closed at pressures above setpoint and
opens at pressures below setpoint.
Specifications
Check Procedure
1. Connect manifold gauges at suction and discharge
access valves at the condensing unit.
2. Set ICE/OFF/CLEAN switch to OFF.
3. The liquid line solenoid valve will de-energize and
the suction pressure will begin to decrease. The low-
pressure control will open at the listed specification.
4. Use the manifold gauge set to increase suction
pressure. Feed refrigerant from the high side access
valve to the low side access valve. Add refrigerant in
small increments to allow the low side pressure to
be monitored. The low pressure control will close at
the listed specification.
Replace the LPCO control if it:
• Will not close at the specified set point.
• Does not open at the specified set point.
! Warning
If discharge pressure exceeds 460 psig and the
HPCO control does not cut out, set ICE/OFF/CLEAN
switch to OFF to stop ice machine operation.
Model
Cut-In
(Close)
Cut-Out
(Open)
RFC2085
RFC2385
22 psig+3 7 psig +3
Revised 8/2003