Weil-Mclain - Honeywell controller issues

Discussion in 'Boiler Forum' started by dayers1109, Nov 28, 2011.

  1. dayers1109

    dayers1109 New Member

    Messages:
    2
    Location:
    cincinnati
    I installed a used Weil-McLain 68 oil-fired boiler. The problem is the unit wants to fire and run whenever I power it on - through the breaker. The thermostat is off and it still runs. I even disconnected the thermostat wires and it will still fire and run when I flip the breaker on. I've checked the controller - its a honeywell but I can't find anything with a model number on it - and the transformer clicks back and forth if I arc the thermostat terminals. When it fires - the pumps don't run, unless I have the thermostat wired back up and set to run. I've turned the unit from vertical to horizontal and that doesn't do anything either - I was wondering if it mattered. Any help I can get (before it gets too cold!!) would be greatly appreciated.
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,948
    Location:
    New England
    It may be set to constantly maintain a temp between the min/max, and when cold, is not up to the minimum, so it probably is just doing what it should, turning on to raise the water temp to the minimum. Double-check the aquastat wiring.
  3. Dana

    Dana In the trades

    Messages:
    2,812
    Location:
    01609
    What jadnashua said. On a number of boilers the burner is controlled only by the aquastat setting, and the circulator pump is controlled by a zone-relay (sometimes integral to the boiler's controls that will also inhibit the circulator even during a call for heat when the boiler temp drops below the low-limit aquastat.)
  4. dayers1109

    dayers1109 New Member

    Messages:
    2
    Location:
    cincinnati
    Thanks Gents - I'll just set the low temp way down and see if that works. Im still thinking that if the thermostat is set to 'off' that it shouldnt fire at all. I'll take a look at the aquastat wireing as well and let you know.
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