Manitowoc S600M, Service Manual

Page: 57 / 103

Section 6 Electrical System
Part Number 80-1630-3
6-17
DIAGNOSING START COMPONENTS
If the compressor attempts to start, or hums and trips the
overload protector, check the start components before
replacing the compressor.
Capacitor
Visual evidence of capacitor failure can include a bulged
terminal end or a ruptured membrane. Do not assume a
capacitor is good if no visual evidence is present. A good
test is to install a known good substitute capacitor. Use a
capacitor tester when checking a suspect capacitor. Clip
the bleed resistor off the capacitor terminals before
testing.
Relay
The relay has a set of contacts that connect and
disconnect the start capacitor from the compressor start
winding. The contacts on the relay are normally closed
(start capacitor in series with the start winding). The
relay senses the voltage generated by the start winding
and opens the contacts as the compressor motor starts.
The contacts remain open until the compressor is de-
energized.
Relay Operation Check
1. Disconnect wires from relay terminals.
2. Verify the contacts are closed.
Measure the resistance between terminals 1 and 2.
No continuity indicates open contacts. Replace the
relay.
3. Check the relay coil.
Measure the resistance between terminals 2 and 5.
No resistance indicates an open coil. Replace the
relay.
ICE/OFF/CLEAN TOGGLE SWITCH
Function
The switch is used to place the ice machine in ICE, OFF
or CLEAN mode of operation.
Specifications
Single-pole, single-throw switch. The switch is
connected into a varying low D.C. voltage circuit.
Check Procedure
NOTE: Because of a wide variation in D.C. voltage, it is
not recommended that a volt meter be used to check
toggle switch operation.
1. Inspect the toggle switch for correct wiring.
2. Isolate the toggle switch by disconnecting the Molex
connector.
3. Check continuity across the toggle switch terminals.
Note where the wire numbers are connected to the
switch terminals, or refer to the wiring diagram to
take proper readings.
4. Replace the toggle switch if ohm readings do not
match all three switch settings.
Switch Setting Terminals Ohm Reading
ICE
1-6 Open
1-2 Closed
2-6 Open
CLEAN
1-6 Closed
1-2 Open
2-6 Open
OFF
1-6 Open
1-2 Open
2-6 Open