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Taco SR504 Switching Relay issue

joanna416 Member Posts: 1
We had a power issue in our house and had to have it restored. When doing so all breakers were turned off and then turned back on... everything is showing current EXCEPT the Taco relay box which means it’s not igniting my hot water heater at all. All the fuses were checked and are fine... reset the breaker and still no power. Is there a manual reset possibly?


  • delta T
    delta T Member Posts: 884
    I had a problem with a Taco SR506 a while back that had me scratching my head. Where are you checking power in the unit?

    My guess is that the transformer in the control is fried. From finally talking to an electrical engineer about my problem, it sounds like during the work in the electrical panel (adding a backup generator and transfer switch) somehow 240 volts was sent to the transformer instead of 120. This can apparently blow the transformer without blowing a fuse.

    I would start there. If you have power going to the unit, and you do not have 24 volts coming out of the transformer it is toast (assuming the fuse is good).
  • lchmb
    lchmb Member Posts: 2,997
    is the green light on? Did you verify power into the l1/l2 terminals? if you have power and fuses are good it sounds like you lost the board...
    check stair switches and service switch for the boiler as well..
    HVACNUT Member Posts: 5,865
    You'll need a voltmeter to see if there's 115v at L1,L2, especially if the green power light is not on.
    If there's voltage but no light it's a bad zone board.