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WeilMclain control unit keeps...melting?

lukasdlukasd Member Posts: 11
edited February 2 in Radiant Heating
I have a WM CG-5 spdn from around 1995. We haven't owned the house that long but I switched over to pex and a cross manifold and things were ok for a while. While the boiler goes up to temp I've noticed that the control box (located inside the boiler) is basically melting from the heat of the boiler when it's running up to temp. That can't be normal right? I see online pics of the insides of other such boilers and they have the control box (UTEC) located in the same place... am I missing something here? The thermostat control is set to about 180-190, but I know it's about 10F off from prior service notes, and the temps I get at the manifold are in the 170 range out to the rads.

I preemptively ordered an extra control box, and sure enough this morning I had to put it in. I also wrapped it in reflective heat shielding for car stuff, and hoping that makes a difference. I attach a pic of the new (but now melted) board and the second new one with the sticky heat insulation trying to shield it. You can already see that the one I put in this morning is already wavy/melty in one or two spots. Boiler working fine once again and the rads are hot.


  • STEVEusaPASTEVEusaPA Member Posts: 4,310
    Better get a pro over there with a combustion analyzer. Could be a blocked flue, or flame rollout
  • SteamheadSteamhead Member Posts: 13,929

    Better get a pro over there with a combustion analyzer. Could be a blocked flue, or flame rollout

    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
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  • DZoroDZoro Member Posts: 1,035
    Fully agree with the guys comments. Strongly suggest turning the boiler off immediately. You are getting flue gasses and temperatures coming into your home. Very dangerous/flammable/deadly.
    At minimum the boiler needs a thorough cleaning and chimney inspection/cleaning.
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 7,194
    I agree with the above posts. Have it serviced before something happens. I would suspect the boiler or flue is plugged or dirty
  • SuperTechSuperTech Member Posts: 1,383
    100% this boiler or the flue pipe is plugged and you are probably in a very dangerous situation. That's flame rollout. Shut it down and call a professional.
  • lukasdlukasd Member Posts: 11
    Thanks guys. Will do.
  • HVACNUTHVACNUT Member Posts: 3,468
    You can see the scorch mark across the bottom of the burner door panel. Not good. Not safe.
  • B_SloaneB_Sloane Member Posts: 54
    Yowser ..!!
    Look at the "spark" terminal ..
    that's Roll-Out for sure
  • lukasdlukasd Member Posts: 11
    edited February 4
    Bit of an update! Had a tech out this morning.

    The boiler is fine, no roll-out really, but the PO (or someone) for some reason only reinstalled one of the two metal panels (the base front cross tie, in the parts diagram) the last time someone was in there. I remember seeing a random piece of sheet metal in the basement that I had trashed and went looking for it as the tech serviced the boiler. Found it in trash I was meaning to take to the dump. Sure enough that was the missing cross tie panel.

    Boiler was cleaned and otherwise serviced, not much soot was found. Everything else looked good, combustion numbers good, heat going into the heat exchanger now instead of out the front panel and the new ignition module much cooler and happier.

  • pecmsgpecmsg Member Posts: 1,465
    Can you post the combustion #’s?
  • lukasdlukasd Member Posts: 11
    @pecmsg I don't have them handy, but I remember the CO number being 22 ppm.
  • pecmsgpecmsg Member Posts: 1,465
    If they were takin there should be a print out at the boiler.
  • SuperTechSuperTech Member Posts: 1,383
    edited February 4
    That makes sense. Quite a bit of heat can escape out the front of the boiler without that panel in place. 22 PPM seems a bit high, usually those boilers burn very cleanly due to lots of excess air. I'm very curious to what the %O2 is and what the over fire and breach draft readings are.

    My biggest concern is how the hell was the boiler is functioning without the fusible link rollout switch in place? That's always on the panel that wasn't in place before.
  • lukasdlukasd Member Posts: 11
    @SuperTech it's actually on the panel that was left in place (8B on the diagram). The CG-5 has two of these panels, and upper (the one that was missing, part#8 in the diagram), and the lower where the roll-out switch is, 8B. In this case the lower panel was mounted where the upper panel was supposed to be (and the roll-out switch was then mounted much higher than it should be)... I imagine in this position for the fusable-link to actually work the way it was intended the boiler would have had to be on fire.

  • SuperTechSuperTech Member Posts: 1,383
    Ok, I'm very glad to hear that it wasn't removed and bypassed. That's an extremely important safety device, given the situation with the control melting the importance of that component cannot be stressed enough. If you have a chance let us know the details of the combustion analysis, I hope your tech was thorough with his evaluation of your boiler.
  • lukasdlukasd Member Posts: 11
    @SuperTech I'll get a copy of the paperwork/numbers tomorrow. The little printer on the thing was kaput and all I remembered were the CO #s.
  • lukasdlukasd Member Posts: 11
    @SuperTech these are the final #s on the boiler.

  • SuperTechSuperTech Member Posts: 1,383
    Well, there's no draft readings. Hopefully the technician just forgot to write it down. I'm glad you didn't get rid of the missing piece of metal and everything worked out.
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