CONTINUED FROM
PRECEEDING PAGE
Is the right HI LED lit (for split vat
units, both HI LEDs lit)?
YES
Is 24VAC present on the Latching Contactor AND does the contactor close?
YES
As HEATING MODE indicator lights, does the right HT LED light (both HT LEDs for
YES
Is 24 VAC present on the
Heating Contactor and does the
Heating Contactor close?
YES
Continued on
next page
NO
NO
NO
NO
Probable causes are:
1. Open
2. Open/defective
3.Broken or improper wire connection
4.Defective latching relay
Probable causes are:
1.Defective latching relay
2.Defective latching contactor
3.Defective interface board
4.Broken or improper wire connection
Probable causes are:
1.Broken or improper wire 
connection
2.Defective interface board
Probable causes are:
1.Defective interface board 
2. Broken or defective wiring
connection
3.Defective heating contactor
