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Weil McLain Ultra 155 b 25 error and Nest

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colek87
colek87 Member Posts: 8
Hello. I am getting the b 25 error. The boiler is on, but not “running”. If I reset it, it will start the routine...the intake fan starts, the ignighter starts, then the fan cycles down for a minute then starts back up. Once it gets to full power, it’s like the ignighter is “blown” out and the fan powers down. No heat.

Here’s what I do to get it to produce heat and stay on for a while: After the restart, I choke the intake funnel by placing a couple fingers over it so it is making the flame stronger. Once I get to around 120-130, it usually stays on.

The system has two zones, one for the whole house (two story), and one for radiant floor in the great room. I also have a gen3 Nest tstat (currently disconnected because it says the voltage is low, maybe need to add common wire from boiler?), now using a heat only two wire tstat.

Also, some water dripping from the funnel and the boiler chamber.

Comments

  • HVACNUT
    HVACNUT Member Posts: 5,861
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    Remove and clear the drain. Be careful as the bung on the HX tends to corrode on the series 2. They've since made revisions.
  • colek87
    colek87 Member Posts: 8
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    Hey HVACNUT! Thanks for the reply. Do you mean the line on th pump on the back of the boiler?
  • HVACNUT
    HVACNUT Member Posts: 5,861
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    The clear tubing at the bottom. Remove it and clear it, the bottom bung of the HX and the PVC to the condensate pump or drain.
  • colek87
    colek87 Member Posts: 8
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    Gotcha. Thx. I’ll try that.
  • colek87
    colek87 Member Posts: 8
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    I removed the pump from the outlet on the boiler and plugged it in to an extension cord and poured water in it. It pumped it out (the water was black, maybe stirred up some sediment in the bottom of the pump?). But it did pump it all out without any issues.

    Were you talking about the bigger plastic tube? I attached a picture. And do you think this is the cause of the b 25 error?
  • colek87
    colek87 Member Posts: 8
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    Just removed the big tubing and WOW, it was bad! Ton of black water and what looked like sand.
  • colek87
    colek87 Member Posts: 8
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    Still getting error. Was working for a while though. It seems that when the temp gets below 25 outside, it starts to have issues.
  • DZoro
    DZoro Member Posts: 1,048
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    Full flush heat exchanger cleaning, and annual maintenance, tune up.
    D
  • colek87
    colek87 Member Posts: 8
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    Will do. Been hard to get someone out to do that. Thx for the advice.