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Transformer and relay

Boston_2 Member Posts: 107
This may be a silly question, but could someone explain to me why is there a need for both a transformer and relay in my boiler? Is it for the gas valve? We had an outdoor reset installed and now once in awhile i get some chatter from the relay? Is it possible the end switch on the reset is causing the relay to hum/chatter?


  • Nighthawk035
    Nighthawk035 Member Posts: 3
    The transformer steps the 110 volt line voltage down to 24 volts to run the thermostat circuit. The relay pulls in when the thermostat calls for heat, and activates the burner(24volts) and the circulator(110volts) at the same time, without mixing the two voltages. If your relay is chattering, you probably have a problem with the 24 volt side.
  • Leo_G
    Leo_G Member Posts: 89
    Chattering usually means time to replace. But first check that the leads to the relay have not come loose.
  • j a_2
    j a_2 Member Posts: 1,796
    Is it a Burnham?
  • Boston_2
    Boston_2 Member Posts: 107
    Yes, it's an older Burnham. I'm still checking the othe suggestions about about voltage.
  • j a_2
    j a_2 Member Posts: 1,796
    I don't see a pic...but take off the front cover and there is a relay in there wiggle it around. Famous for the chattering..on Burnham. Loose connection or something..when we install them. We put a tiewrap around it.....saves a call back or 2.... If bad its a common and cheap part....I am only guessing because I am not there and don't see a pic