Steve
Field uses the potter Blumbfiled type relays, I am not sure as I do not have one in front of me but it is a plug in type relay.
Line voltage I think enters from the upper vertical pins as a switch leg, the lower pins that are horz are for the 24Vt coil.
Power enters the relay box, and then a neut would go to the blower motor and then to the transformer.
When the relay is made 24 vts runs throught the relay and into a time delay, to a pressure switch before it allows the burner to light.
I have had to replace these relays in the past as they do wear, Granger sales this relays give them a call as they stock it.
Bernie
