Manitowoc Ice S1800 service manual Model Automatic Shut-Off and Restart, Troubleshooting PTCR’s

Electrical System Section 6

S-Model Automatic Shut-Off and Restart

When the storage bin is full at the end of a harvest cycle, the sheet of cubes fails to clear the water curtain and will hold it open. After the water curtain is held open for 30 seconds, the ice machine shuts off. To assure the PTCR has cooled, the ice machine remains off for 3 minutes before it can automatically restart.

The ice machine remains off until enough ice has been removed from the storage bin to allow the ice to fall clear of the water curtain. As the water curtain swings back to operating position, the bin switch closes and the ice machine restarts, provided the three-minute delay period is complete.

L1

L2

CONTACTOR

CONTACTS RRUN CAPACITOR

C

R R

Troubleshooting PTCR’s

WHY A GOOD PTCR MAY FAIL

TO START THE COMPRESSOR

The PTCR must be cooled before attempting to start the compressor, otherwise the high starting torque may not last long enough.

For example, if the PTCR is properly cooled, say 60°F (15.6°C) when the compressor starts, it will take .25 to

1.0seconds before its temperature reaches 260°F (126.6°C), and current flow is stopped.

If the PTCR is still warm, say 160°F (71.1°C) when the compressor starts, it will take only .125 to .50 seconds before its temperature reaches 260°F (126.6°C), and current flow is stopped. This decreased time may be insufficient to start the compressor.

A good PTCR may be too hot to operate properly at start-up because:

• The ice machine’s 3-minute delay has been

S

COMPRESSOR

PTCR

SV1506

overridden. Opening and closing the service

disconnect or cycling the toggle switch from OFF to

ICE will override the delay period.

• The control box temperature is too high. Though

rare, very high air temperatures (intense sunlight,

During Start-Up (First .25 - 1.0 Seconds)

L1		L2
CONTACTOR	RUN CAPACITOR
CONTACTS
R
C	R	R
S
COMPRESSOR
		SV1507
		PTCR

After Start-Up

(Current Flows Through Run Capacitor)

etc.) can greatly increase the temperature of the

control box and its contents. This may require a

longer off time to allow the PTCR to cool.

• The compressor has short-cycled, or the compressor

overload has opened. Move the toggle switch to OFF

and allow the compressor and PTCR to cool.

Continued on next page …

6-16 Part Number 80-1634-3