Hot Water Boiler leaking water out of pop off valve

Old 05-13-11, 09:35 PM
Thread Starter
Join Date: May 2011
Location: USA
Posts: 6
Upvotes: 0
Received 0 Upvotes on 0 Posts
Hot Water Boiler leaking water out of pop off valve

My boiler was leaking water out of the high pressure relief valve and I replaced it thinking that would cure the problem. After I had replaced it I still had the same problem. After going on to the internet I found that usually this is caused by the expansion tank having a ruptured bladder which eliminates it from controling the water pressure into the boiler. I replaced it and it fixed the problem. Also found out that it is easy to check and see if the bladder is ruptured. All you have to do is feel the top of the tank and then the bottom of the tank and if it is as hot on the bottom portion as it is on the top then there is water in the bottom of the tank and so the bladder is ruptured and needs to be replaced. Of course this has to done with the boiler on and hot. This was a cheaper fix than if it had been the high pressure relief valve. Hope this helps someone.
Old 05-14-11, 06:35 AM
NJT's Avatar
NJT is offline
Join Date: Oct 2006
Location: USA
Posts: 19,710
Upvotes: 0
Received 8 Upvotes on 6 Posts
Hi Woody, thanks for your post.

One thing we usually recommend is replacement of the relief valve every 5 years or so, but there are probably millions of systems out there with 20-30 year old relief valves on them.

Something to add to your maintenance schedule... check the air charge in the expansion tank at LEAST every two years! They DO lose air in normal operation, about 1-2 PSI / year. By keeping the air charge correct, you eliminate excessive flexing of the bladder and the life of the tank is GREATLY increased.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: