I lost electric to my hydronic heating (mine is the Oasis Combi) and my symptom was that I was getting only about 60Volts on the hot wire. The problem turned out to be a snap connector which connected the breaker circuit to the 3 wires running forward to the heater. I had to remove the breaker box to access the space behind it where I unsnapped that connector and attempted to bend the blade on the black circuit then snapped it together again and then I had the proper AC voltage on the circuit.
I determined it was the snap connector by connecting white to ground at the heater then measure resistance at the breaker box and after the snap connector, then did black to ground connected at the heater, tested again, then black to white, and determined that black yielded an open connection from the breaker box but it was fine from the other side of the snap connector. Thus the break was in the snap connector.
Mike
