Steam Boiler keeps overfilling

lhamwey

We have a steam heating system in our home with radiators throughout the house. When we turned it on this winter everything was normal, then after a few days we got really bad water hammering. To the point where it was shaking the walls and so loud we could not sleep. We called out a plumber who said that our boiler (Burnham Independence) was overflowing and there was just too much-standing water in the pipes. He showed me what level the water should be should be in the sight glass and told me to drain it it out to that point. I did and it worked for a few days before I noticed once again the boiler was overfilling again and the water hammering returned.

I drained the whole thing and let the Programmable water feeder fill up the boiler to the proper level. I also noted the reading on how many gallons it filled so I can see if that was where the water was coming from. A few days go buy and once again it is overfilled. I checked the water feeder reading and it was the exact same as when I last filled it, so I assume the additional water is not coming through there.

My question is, where could the water be coming from and is there is a troubleshoot/solve this I could try on my own before calling out another plumber? Right now when it gets bad every few days I just drain it some, but that seems like a inefficient band-aid rather than a solution.

109A_5

Hello lhamwey,

Assuming you have a VXT auto water feeder, it is just a timer (when it is actually active) with the water going through a calibrated orifice, it does not measure water flow like a utility type meter does. So the feeder's valve could be leaking with no record of the added water or a bypass valve could be leaking too. Is there a valve that shuts off the water to the whole system, if so I'd try that to see if it stops overfilling the system. If so keep an eye on the level so it does not get too low until it gets repaired correctly. Do you have a DHW coil ? If so that could be leaking into the boiler. Pictures of your system help us help you.

EBEBRATT-Ed

Either the manual feed valve or the auto feeder is leaking by. You probably don't have a tankless heater on that boiler

tcassano87

i assume you don't, but I do you have an indirect HW tank off the bottom of your boiler? The relief valve would most likely be blowing off as well but if you it's possible the coil is cracked inside the indirect tank. Otherwise it's like others said, your automatic feed is no good, the bypass valve is passing or, a long shot you're low water cutoff isn't telling the feeder that its filled and turning it off