Checking combustion air auxiliary contacts
With the burner operating, trip the burner circuit breaker (Fig. 9).

Figure 9. Burner and circulating pump circuit breakers.

This should cause the auxiliary contacts to open. The following reactions should occur, indicating that the contacts are operating properly:

1. The burner should shut down.

2. The Combustion air auxiliary contacts light on control panel should be the first light to go out.

3. Fireye flame monitor should read 3 TO P INTERLOCK OPEN.

Reset burner circuit breaker.

Checking low combustion air switch
With the burner off, unlatch the auxiliary contacts module and physically remove it from the burner motor starter with wires attached. Pull out the blue plunger on the module and hold it out so as to close its contacts. (Fig. 10).

Figure 10. Removing auxiliary contacts module and holding plunger out.

Restart the burner. Trip the burner circuit breaker. After 4-5 seconds the following reactions should occur, indicating that the pressure switch is operating properly:

1. The burner should shut down.

2. The limits made light on control panel should be the only light to go out.

3. Fireye flame monitor should read 3 TO P INTERLOCK OPEN.