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15
Electrical System
Q-Model Automatic Shut-Off and Restart Troubleshooting PTCR’s
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 7 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.
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 1.0 seconds before its temperature
reaches 260°F (126.6°C), and current flow is
stopped.
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.
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.
During Start-Up (First .25 - 1.0 Seconds)
SV1506
SV1507
L1 L2
CONTACTOR
CONTACTS
C
R
S
R R
COMPRESSOR
RUN CAPACITOR
L1 L2
CONTACTOR
CONTACTS
C
R
S
R R
COMPRESSOR
RUN CAPACITOR
PTCR
PTCR
A good PTCR may be too hot to operate properly at
start-up because:
• The ice machine’s 3-minute delay has been
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, 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.
After Start-Up
(Current Flows Through Run Capacitor)
Continued on next page…