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Hitting a wall on old system

fatty_2fatty_2 Posts: 54Member
I thought I'd have this old system up and running by replacing the relay control. I wired and rewired half a dozen times without any response from the system.

By jumping the Y and R terminals I can get the system to open the vent, start the gas, ignite via electric ignition. No pump action and certainly not safe, I just wanted to see if there was anything working at all.

That's the only way I can get ANY response out of this one. I'm just stumped.

Included is the Wiring Diagram off the front of the boiler and a diagram I drew while stumped that shows how I have it wired.

Thanks so much....



  • IronmanIronman Posts: 5,124Member
    Bad Holding Coil

    The coil is bad in your relay. Double check that your wiring matches your diagram. It's correct, but I would move the wire on relay terminal 4 to connect to R" instead of "G" if your boiler short cycles at all. (Has to do with current draw through the heat anticipator).

    Replace your relay.
    Bob Boan

    You can choose to do what you want, but you cannot choose the consequences.
  • fatty_2fatty_2 Posts: 54Member

    thanks ironman, I also thought it was the relay so this is a problem i've had after replacing it. I'll try switching to the 4 to the R
  • fatty_2fatty_2 Posts: 54Member

    Since the relay is new - is there a method of testing it with a multimeter that would prove it has gone bad... I really don't want to order another one and wait for it. It's getting to be a very cold jobsite.
  • DelDel Posts: 52Member
    edited December 2010
    run 24V through the coil

    and see if the relay contacts pull in (test for continuity) 0 resistance, you are closed and infinite you are open.  My meter has a continuity tester that beeps, maybe yours does too. When the contacts pull in, you should have 24V at the ignition control...I believe between terminals 2 and 6, and 120v at circulator. If you are not getting that, something is up. Double check the relay.....make sure it is the right type DPST.  Could also be a bad transformer, or loose hot or neutral wiring somewhere.  Make sure there is 120V at the transformer, and 24V coming out of it.  Hope you can fix it!
  • IronmanIronman Posts: 5,124Member

    Your transformer is good because it energizes the ignition. If you jumped "R & G" and nothing happened, the holding coil in the relay is bad. If it brought the system on, then your thermostat or its wiring is bad.
    Bob Boan

    You can choose to do what you want, but you cannot choose the consequences.
  • DelDel Posts: 52Member
    If you're

    In a bind, just get a relay box to control the circulator and use the end swith off the relay box to control the boiler. Are you sure there is not a low limit control in there? That could be why the circulator does not turn on right away.
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