Our boiler's backflow preventer valve started to leak out of the vent around Thanksgiving. I read that it may have to do with system pressure and it may stop, which did stop dripping after a few days. Then around Christmas we have all 3 zones going with family in town and the dripping started again. I have a Solo cup under it and after 3 weeks or so the cup is full.
My question is, at this point is the issue probably either a old valve or crud effecting the valve inside? If that is the case, I would probably rather just spend the money on the valve to replace it unless it is not too time consuming to try and clean. What suggestions would you have for me? Thanks
Best Answer
This can happen if the pressure difference goes the other way, like if the water feed is shut off. Some common models like the Watts 9D-M3 have rebuild kits available, but they cost almost as much as a replacement valve, which is $30-35 in the US. (I just checked that at one of the big box stores here)
So the answer is replace it, though a plastic cup after 3 weeks is pretty slow. Note that since this particular model has (threaded) union connectors, if you get the same model as a replacement, you can swap it in without soldering.