Replace 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 by switching the main circuit breaker to OFF.
2. Open PLC enclosure.
3. Locate and remove control relay (Figure 12, Item 20).
While the control relays all look identical, they are not all interchangeable. The exhaust
fan relay, interior lights relay, and blackout lights relay are identical, and the same
replacement relay may be used for all three. The remaining relays are interchangeable,
4. Install replacement control relay (Figure 12, Item 20). Ensure the replacement relay is firmly seated
and securely retained in place by the clamp.
5. Close enclosure, connect power, and operate PLC.
6. Monitor for normal operation.
Figure 12. Replace a Control Relay.