Leaking boiler pressure relief valve


Old 03-04-16, 05:35 AM
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Location: NY
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Leaking boiler pressure relief valve

I noticed a puddle on my floor coming from the boiler about a month ago and ignored it. I know thats bad but my previous puddle 3 yrs ago lead me to find a leaky boiler that I had to replace and I wasn't in the mood to push around and install another 650 lb monster again! Anyway to my pleasant surprise the boiler is fine and the leak is from the pressure relief valve - an Apollo 10408.

I followed the post here about checking the expansion tank and found my tank completely full - it must have ruptured. I replaced it with a previous one that still held air and have it at 12 lbs.

I 'flushed' the PRV for 5 seconds a few different times, but it still leaks. Should I assume it just 'bad'? Can it be taken apart and cleaned or fixed? Would it get damaged from a non-working expansion tank? If it comes with a new Burnham boiler then it is only 3 yrs old. Otherwise it would have been new in in 2001 when I rebuilt the boiler system.

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Old 03-04-16, 05:41 AM
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If the pressure in the system is correct and lower then the relief valves blow off point, then yes, replace it.
Old 03-04-16, 07:22 AM
Join Date: Jan 2010
Location: North East Kingdom of Vermont
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I'm just a Real Estate Broker; but I've tried cleaning/clearing a weeping Pressure Relief Valve several times; but met with success only once.

It seems that once they pop, there's seldom a way to get them to re-seat completely, as if the sealing gasket has been permanently dented, or some microscopic grit gets itself embedded in the gasket, preventing a tight seal.

I have one right now that's weeping about a cup of water per week (plus whatever evaporates), one drop at a time, and I'll replace it at the end of winter.

I don't know how to fully bench test one that I've cleaned before re-installing, and it is so frustrating to partially drain the boiler to do the replacement, I'd have to think long and hard before I trust my efforts at cleaning again.

I suppose, if you have exceptionally clean water, completely free of mineral deposits, cleaning is a possibility; but I think even the professionals are leery of doing the quick annual releases (flushes) to simply test the Valve as a safety feature.
Old 03-05-16, 02:51 PM
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Well, I took a few mins to remove and inspect it. I installed this boiler so I have good valves all around so it wasn't a problem draining a small amount of water to take the valve out. There isn't really anything that can be taken apart though - it looks like the whole mechanism is pressed into the brass housing. So I flushed it and used some Lime-Away to clean it as best I could, then put it back on.

Success! (for now) No leak, but I'll keep my eye on it and replace if need be.

Thanks for your input.

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