Power Supply; High Pressure Cutout (Hpco) Control - Manitowoc Multiplex N2Fusion Service Manual

Component Check Procedures

POWER SUPPLY

Location
The 24 VDC power supply is located behind the left side
panel.
Function
Reduces and converts voltage for use on the control circuit.
Specifications
Steps down voltage from:
90 - 264/50-60/1 VAC to 24 VDC 8.4 A
Check Procedure
1. Inspect for correct wiring.
2. Check for line voltage at transformer primary CN1.
• No line voltage present - Refer to power relay
and toggle switch check procedures.
• Line voltage present - Continue diagnostics.
3. Check voltage at transformer secondary CN3.
• 24 VDC present - Transformer is OK.
• 24 VDC is not present - Isolate secondary wiring
and check for 24 VDC.
• 24 VDC present - Repair wiring or replace
effected component(s).
• 24 VDC is not present - Replace Power Supply.
• One LED light - constant on to indicate power is
applied - located at the lower left corner of CN3.
POWER SUPPLY BOARD
46

HIGH PRESSURE CUTOUT (HPCO) CONTROL

Function
Protects the compressor by interrupting the control signal
to the control board. Excessive high side pressure operates
the HPCO. The HPCO control is normally closed, and opens
on a rise in discharge pressure.
Location
Above the ice compressor.
Specification
Refrigerant Type Cut-Out
R404A 2413 kPa ±24.13
bar ±.69
R290
350 psig ±10
The HPCO automatically resets when the pressure drops below the cut-in
Check Procedure
1. Verify the filter and condenser are clean.
2. With power off, isolate by disconnecting the wiring
connectors.
3. Check continuity across the terminals with an ohm
meter.
• Low resistance = Continuity is good.
• Open (OL) = Replace HPCO.
4. Replace wires on HPCO terminals and also connect volt
meter across the HPCO terminals.
5. Install a high side gauge and initiate a start sequence.
6. Watch the refrigerant pressures when the compressor starts.
• HPCO opens below cut-out set-point - Replace
the HPCO
• HPCO opens above cut-out set-point - Locate
the root cause - Fan motor defective, dirty
condenser, refrigeration system issue, etc.
Part Number 020007115 06/27/2019
Section 7
Cut-In
1723 kPa 17.23 bar ±.69
250 psig ±10