L8418A Honeywell Aquastat

Discussion in 'HVAC Heating & Cooling' started by robertjulius, Jan 8, 2009.

  1. robertjulius

    robertjulius New Member

    Messages:
    2
    The aquastat on my boiler has been malfunctioning. Sometimes it works on its own, sometimes I have to help it along. I can get it to work if I press on the square metal piece attached to the small spring. It appears that the contacts on the electromagnetic relay on the aquastat do not line up properly. Is there any way to adjust the relay so that it works more reliably, possibly adjusting the length of the spring or bending in the frame of the relay a bit? It is an L8418A 1009 and I have been told that it has been replaced by an L8418A 1017. Thanks for any advice.
  2. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    Nope, no adjustments can be made here. The problem is with the relay and it sounds like it's a few hrs. away from heading south. Replace the control.
  3. robertjulius

    robertjulius New Member

    Messages:
    2
    Honeywell L8148 A 1009 Parts

    Any idea who sells parts so I can rebuild the Honeywell L8148 A 1009? I replaced it with the L8148A 1017 and was hoping to repair this one to have as a back-up. I am trying to find a supplier of the electromagnetic relay,
    Part Number 131630MZMS 17.
  4. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    I doubt that you can repair it and even if you found a source for the relay it would probably cost more than the whole control. Sid Harvy's will take it and give you a core charge though.
  5. b_randolph

    b_randolph New Member

    Messages:
    1
    Location:
    NJ
    Same Issue

    Hey Man, did you get any viable solution for the above issue, as I had the same issue with my furnace, your help will be much appriciated. (see1ce at yahooo doot coom)

    Ths
  6. cormit

    cormit New Member

    Messages:
    2
    Location:
    Kasilof, Alaska
    I too suspect I have an issue with a Honeywell L8148A 1009.
    Question is this: When thermostat closes the circuit (calls for heat) .... should the circulator terminals C1 & C2 become instantly energized, or must the boiler come up to temperature first before the circulator will energize?
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,892
    Location:
    New England
    Some do, some don't...your operations manual should tell you. It's important that the circulator comes on before the water gets too hot in the boiler, but it doesn't need to come on immediately. The logic may wait until it's sure the boiler fired or the temp starts to rise. And, it often works out more efficiently if it continues to run after the boiler turns off to purge the heat you paid for. If the boiler temp is already warm, the circulator may turn on immediately, when it is cold like from a long off period, it might not. Depends on how the acquastat is wired in the control circuitry.
  8. cormit

    cormit New Member

    Messages:
    2
    Location:
    Kasilof, Alaska
    Thank you Jim for your reply. Was hoping for an easy way to determine if the Honeywell control was working properly or not. I'm using my oil fired boiler through a heat exchanger that is connected to an outdoor wood fired boiler. I have an aquastat that interrupts the power to the oil gun. It is set a 100˚. As long as the incoming water from the wood boiler is at or above 100˚..... the gun will not get power, but the circulator circuit should. If I let the wood boiler run out of wood (leave home for a few days) ... and the water temp drops below 100 ..... the oil boiler will come and operate normally, which it does just fine. When the gun is not going to come ..... on because the incoming water is hot enough .... I still need the circulator to respond to the thermostat call for heat. That does not seem to be happening. Could connect a secondary power source to the circulator ..... also prompted by the thermostat ...... but would have to figure out how to prevent one circuit from energizing back through the other.
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