Manitowoc S0850M, Service Manual

Page: 55 / 100

Section 6 Electrical System
Part Number 80-1558-3
6-17
There are other problems that may cause compressor
start-up failure with a good PTCR in a new, properly
wired ice machine.
• The voltage at the compressor during start-up is too
low.
Manitowoc ice machines are rated at ±10% of
nameplate voltage at compressor start-up. (Ex: An
ice machine rated at 208-230 should have a
compressor start-up voltage between 187 and 253
volts.)
• The compressor discharge and suction pressures
are not matched closely enough or equalized.
These two pressures must be somewhat equalized
before attempting to start the compressor. The
harvest valve (and HPR valve on remotes) energizes
for 45 seconds before the compressor starts, and
remains on 5 seconds after the compressor starts.
Make sure this is occurring and the harvest valve
(and HPR solenoid) coil is functional before
assuming that the PTCR is bad.
CHECKING THE PTCR
1. Visually inspect the PTCR. Check for signs of
physical damage.
NOTE: The PTCR case temperature may reach 210°F
(100°C) while the compressor is running. This is normal.
Do not change a PTCR just because it is hot.
2. Wait at least 10 minutes for the PTCR to cool to
room temperature.
3. Remove the PTCR from the ice machine.
4. Measure the resistance of the PTCR as shown
below. If the resistance falls outside of the
acceptable range, replace it.
Manitowoc PTCR’s 8504993
!
Warning
Disconnect electrical power to the entire ice
machine at the building electrical disconnect box
before proceeding.
Model
Manitowoc
Part Number
Cera-Mite
Part Number
Room
Temperature
Resistance
S0850M 8504993 305C19 18-40 Ohms
SV1540