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Weil mclain combi circulator wont turn off

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Multiman
Multiman Member Posts: 35
in Gas Heating

Circulator pump runs constantly, even when no call for heat from thermostat or the bypass wire at boiler.

Recently replaced expansion, relief valve, water feeder, and 3 way valve. Circ pump only turns off when disconnected from 1107-1 brain. Otherwise, pump runs constantly.

Replace brain? It has already been replaced once. 12 yr old unit.

Comments

  • Multiman
    Multiman Member Posts: 35

    Could be 3 way valve. We disconnect 3 way valve, circ pump stops.

  • Multiman
    Multiman Member Posts: 35

    Argh!!!! We found 3 brains on shelf and 3 old 3 way valves! No wonder they discontinued this combi!

  • hot_rod
    hot_rod Member Posts: 26,645
    https://forum.heatinghelp.com/discussion/comment/1878302#Comment_1878302

    When that many components fail in a short period of time, it might be time to troubleshoot the troubleshooter.

    Failed waterside components are often directly related to the water quality, both boiler side and potable water side.

    Tankless and combis in hard water conditions need occasional descaling, preventive maintenance. Boiler side water needs to meet the spec in the manual.

    They are not at all like a tank water heater when it comes to hard or aggressive water.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    GGross
  • 109A_5
    109A_5 Member Posts: 3,485
    edited December 21

    What LEDs are presently on with the circulator constantly running?

    image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • 109A_5
    109A_5 Member Posts: 3,485
    edited December 21
    https://forum.heatinghelp.com/discussion/comment/1878273#Comment_1878273

    Sounds like the 3-Way valve. Since its End Switch can directly produce a call for heat.

    Personally if it was my boiler, since the 3-Way valve seems to be a chronic issue I'd replace it with another (different) 3-Way valve or two Zone Valves one Normally Open and one Normally Closed. An interfacing electrical wiring harness would have to be made.

    Sadly this is beyond the scope of most HVAC contractors and Plumbers. And then there is the dreaded liability thing.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • kcopp
    kcopp Member Posts: 4,630

    Is this a CGt?
    I have had the issue where the heat stays on w/ the Honewell 3 may valves. This will happen if the valve gets stuck. Water quality often tends to be the issue.

  • 109A_5
    109A_5 Member Posts: 3,485

    @kcopp I believe it is a CGt.

    Must be so some pretty bad water if a new valve is getting stuck within weeks of replacement. I would imagine much of the water was replaced to change the valve.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • kcopp
    kcopp Member Posts: 4,630

    Duplicate post…

  • Multiman
    Multiman Member Posts: 35
    edited December 23

    I am so discouraged. When looking around, we found on the shelf nearby THREE old brain boards, and THREE old three way valves. This is a unit that is about twelve years old. No wonder Weil Mclain discontinued it.

    The water is city reservoir water, considered to be good quality water, although some have said lately that there has been more of a problem with sediment. These are ancient triple deckers in an old factory town; I'm not going to put a whole house water filter on it, nor am I going to put an in-line filter on for this particular unit.

    Some twelve hundred dollars at least over the last six months in repairs. So frustrated. I asked my HVAC plumber to price out a replacement. I'll make a separate post for recommendations for replacement.

  • 109A_5
    109A_5 Member Posts: 3,485

    The thing is, if water quality is truly the underlying issue and the "brain boards" and three way valves were all swapped out in sets each time the unit acted up, a water filter may be your the best defense. Sediment may cause the valve to stick. If the water is that poor as far as heating equipment goes a new boiler may have its own set of issues from the water quality issues.

    Has the water been tested and compared to the Weil McLain specification for that boiler ?

    For better or worse and for various stimulus reasons, but mostly Engineers like to eat and have a roof over their heads. So to eat and have that roof they need to get paid. So they keep coming up with new and different designs, some better than others.

    Since there is so many parts lying around, if it was me I'd be figuring out what the issue with the sticking valve is. I do realize not everyone can do that.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • kcopp
    kcopp Member Posts: 4,630

    Dont confuse the water from the town as the system water. System water is a closed set up.

    The CGt (if that is the unit… still didnt get confirmation) The 3 way valve is on the closed part of the system.

    3 way valve does not touch the city water. tell us more about the system… baseboard? cast iron rads? convectors? What is the piping to everything like? Pex? copper? Polybutylene?

    I am 99% sure its not a board issue. The cartridge on the 3 way is easily replaced.

  • 109A_5
    109A_5 Member Posts: 3,485
    https://forum.heatinghelp.com/discussion/comment/1878667#Comment_1878667

    @kopp Don't they use city water to refill the system every time the valve fails and needs to be replaced ? Potentially adding a new load of bad stuff to help ruin the new valve.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • kcopp
    kcopp Member Posts: 4,630
    https://forum.heatinghelp.com/discussion/comment/1878670#Comment_1878670

    Not that much water…. maybe 2 gallons to top it off.

  • Multiman
    Multiman Member Posts: 35

    Baseboard with all copper piping. The city water is generally very good. But I do think that there was fairly recently some issue with cloudy water with the city flushing all the pipes - I doubt that coincidentally that would have been the same day that the water went in. I do know that the water that came out was dirty looking, when they drained it.

    The valve that the plumber put in is a Honeywell VC8710-03. The system is a Weil Mclain discontinued combi, cgT 5 pin series 2, made in 2014. We tested all the connections, and it's clearly that the valve has failed yet again, is stuck on open yet again.

    The quotes for replacement are insane. Pretty much everything on this unit has been replaced recently, in like the last 6 months - the 3 way valve, the expansion tank, the overflow relief valve, the water intake actuator. I only wound up with managing this building about a year ago, and have no communication with the previous mgr, just know from his asst that the unit has always been problematic.

    I am quite sure that the plumber would have refilled the system with city water. Certainly, if there were a way to get the water in, I could use distilled water to refill it.

    Is there a better 3 way valve to use as a replacement?

  • 109A_5
    109A_5 Member Posts: 3,485

    Seems the Honeywell VC8710-03 has been discontinued and that is just the actuator not the actual valve.

    image.png

    Seems the replacement actuator is " 3-Way Valve Actuator for CGT Boilers, 635-100-023 "

    https://www.supplyhouse.com/Weil-McLain-635-100-023-3-Way-Valve-Actuator-for-CGT-Boilers

    However if the actual valve is sticking just changing the actuator may never help.

    image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • kcopp
    kcopp Member Posts: 4,630

    I ended up w/ two of these swapping out the wiring harness and converting out the CHt to a CG… I then installed an electric WH.

    In effect you disable the valve actuator, push the cartridge into the heat only mode and the wiring is removed so it will not be used and the combi any longer.

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