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Weil McLain Ultra 155 b 25 error and Nest

colek87colek87 Posts: 8Member
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.


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