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Taco 502Sr

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I've got a taco 502sr. I need to replace the ice cube relay. From what I can find out they're supposed to snap in. . I can't get the old one to snap out. Is there a trick to pull this relay? Thanks

Comments

  • HydronicMike
    HydronicMike Member Posts: 253

    Not all versions had replaceable relays…pictures?

  • SteveSan
    SteveSan Member Posts: 293

    If your SR502 has a metal cover and TT connections on the tstat then the ice cube relays are replaceable. If it has a plastic cover, RW tstat connections, and LED are in the front of the control then the relays are not replaceable.

  • kurt_6
    kurt_6 Member Posts: 9
  • kurt_6
    kurt_6 Member Posts: 9

    Unfortunately it's the plastic cover version. So it's no repair and I have to swap it out? I appreciate the help guys

  • HVACNUT
    HVACNUT Member Posts: 7,245

    Those are not cube relays. So what's going on, one zone works, one doesn't?

    How did you reach the conclusion that its a bad relay? You've done all the Occam's Razor stuff? Jumped out R and W. Checked the fuse, etc.

  • 109A_5
    109A_5 Member Posts: 3,485

    The relays are replaceable, you just need circuit board repair skills. I too am curious how you came to the conclusion that it is a bad relay.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • kurt_6
    kurt_6 Member Posts: 9

    I'm just a chucklehead homeowner trying to get things done. Didn't have a tester available. No heat when thermostat clicks on. Led Power light works on the SR 502. Boiler and circulators do not turn on. Boiler works on the domestic hot water side of things. I disconnected the thermostat and closed the circuit on either zone nothing happened. So my guess was the clear plastic relay was the one that starts the boiler and sends the message to the two black relays which my guess is what sends the message to the circulators to turn on. This is where I put these sheepish shrugging shoulders emoji if I could find one. Thanks guys

  • HVACNUT
    HVACNUT Member Posts: 7,245
    edited November 22

    So NEITHER heat zone works? No Red lights on the SR502 when thermostats turned up? Did you try to jump R and W at the SR502?

    Domestic hot water is ok because the boiler has a tankless coil?

  • 109A_5
    109A_5 Member Posts: 3,485

    Looking at the picture more closely, it looks like there is a trail of corrosion from top to bottom that caused your failure. And yes the relay with the clear housing does not look too healthy. It is best to replace the unit and stop whatever was leaking on it so it does not happen again.

    image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    Alan (California Radiant) ForbesHVACNUT
  • kurt_6
    kurt_6 Member Posts: 9

    No red light neither zone circulator starts nor does the boiler start from the thermostat. And yes domestic hot water has the tankless coil and does work.

  • kurt_6
    kurt_6 Member Posts: 9

    I didI did have an indoor rain event this past summer when a bucket split while changing the water in my aquarium.☔

  • kurt_6
    kurt_6 Member Posts: 9

    I want to thank everybody for their help. I really do appreciate it.

  • 109A_5
    109A_5 Member Posts: 3,485

    Maybe, if that happened above the SR502. There is way more corrosion in there than I care to see. Looks like it leaked in through multiple places.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    kurt_6
  • HVACNUT
    HVACNUT Member Posts: 7,245

    Well, there you go. No piping above the relay? Good eye @109A_5

    kurt_6