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Relay Activates pump for unknown reason?

pm1176 Member Posts: 1
edited August 2016 in Controls
Radiant floor heat. Wirsbo two-wire Thermostat. Four Wire valve bodies. Taco SR504 switch relay.

For some reason..about a week ago, one zone decides that the circulation pump needs to turn on and run but the valve remains closed. I can open the valve both manually and by the T stat and the audible click lights up the orange lights on the Uponor Zone Control module. The red light "D3" remains lit no matter all times. Any leads on how to stop this issue or what is causing this? Faulty valve? This is on an oil fired boiler unit and prior to a week ago, the system would only fire off for domestic hot water use- no need for floor heat during this time of year. Thank you all.

***red light can be seen in one photo without flash****

Are thermal valves better than motorized valves or is there a better one out there?


  • Jamie Hall
    Jamie Hall Member Posts: 16,514
    The end switch on the valve is controlling the circulator? That's common enough. If so, that end switch isn't opening.

    In general: figure out what switch or relay is actually controlling the ckculator (this may take some research and wire tracing) and the odds are good that that contact isn't opening properly.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Paul48
    Paul48 Member Posts: 4,470
    Why do you have a switching relay, and a zone control, and how did you marry the two?
    JUGHNE Member Posts: 8,650
    Stuck long as the homeowner is not watching. o:) ....a good "thump" with the rubber handle of a screwdriver might open that switch. This is high tech....knowing where to apply the "thump".
    So carefully whack each valve and wait for the pump to stop. Might work.....just don't dent anything.

    For this technique I support one side of the suspect with one hand and apply the persuader with the other has worked for a lot of stuck items.
  • BobC
    BobC Member Posts: 5,208
    Rubber handled screw drivers were one of my favorite technician aids when repairing the mail sorting machines at the post office.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Paul48
    Paul48 Member Posts: 4,470
    It was a heck of a lot faster than checking voltage at a couple hundred contact blocks. I worked on printing presses that had the old relay-logic controls.

    Back in the late nineties, I had a new car that kept shutting off, while driving. I took it back to the dealer, and he gave me a loaner. At the end of five days, he told me I needed to take it to a dealer in another town. He said they have better equipment. So, I took it to that dealer, and told him what the other one had said. He laughed, and said,"they have the same equipment I have". Anyway, I left it and he called 2 hours later and said it was all set. When I picked it up, he said it was the computer ($100 back then). I asked him how they found the problem. He said, " we take the computer out of the back of the glove compartment, and put it on the floor of the car. Then we send 2 guys out in the car, and one taps on the side of the computer. When he did that, it died".
    So........It's not mutually exclusive of any one trade.