Test a Control Relay
This equipment operates at high voltages. Use extreme caution, observe all warnings,
and follow all safety procedures. Failure to observe safety precautions may result in
injury or death to personnel.
1. Disconnect power at the main circuit breaker.
2. Open PLC enclosure.
The dryer exhaust fan relay, interior lights relay, and blackout lights relay are
interchangeable, and may be used when testing a suspected bad relay among the three.
The burner status relay, burner power relay, high temp alarm relay, low water alarm
relay, and burn lockout alarm relay may be interchanged as well for testing.
3. Locate and remove suspected malfunctioning control relay (Figure 22, Item 47) and replace with a
known good relay.
4. Close enclosure, connect power, and operate PLC.
5. Monitor for normal operation.
Figure 22. Test a Control Relay.