I have a Weil-McLain Boiler. When the house thermostat is set at say 68 the boiler keeps heating past this temperature and keeps going to like 80, 90, 100. We have to turn off the power to the unit to shut it off. I don't know what to do. The furnace worked fine for the past 5-10 years that we've had it. I don't remember for sure how long. The thermostat is newer though. It starts fine. It seems to run fine. It just wont stop at the temperature. Help.
I believe we will have to go back and forth a few times to answer this question. I need more information to get started and I will give you some information to get you started.I need the whole model number of your boiler this will be found on a tag somewhere on the boiler.I also need to know if your house is one zone or more and if there is a hot water tank connected to your boiler. If your house is a single zone with one thermostat then the first thing to eliminate is the thermostat. Doesn't matter its age it can be new and be broken.With the power off remove the face plate on the thermostat and disconnect the wire connected to the w terminal. Put a small wire nut on the wire and turn on the boiler, if it is stays off for some time then you have your problem.If you turn on your boiler and a damper on the flu pipe opens then there's a clicking sound and the pump starts then we need more information. Shut of the power, put your wire back and put your thermostat back.
