Relay Operation Check - Manitowoc S300 Technician's Handbook

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.
Part Number 80-1479-3 7/10 155