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Oil fired boiler problem!!

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T2
T2 Member Posts: 4
Hi all. I have water coming from my pressure release valve, just started this week. Probably 2, 5 gallon buckets full a day. The PSI when hot doesn't seem to go over 20, and cold, it doesnt go below 12. I'm led to believe it is just a faulty pressure relief valve. Sound correct? Thanks a lot!!

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  • EddieG
    EddieG Member Posts: 150
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    Don't....

    Don't trust the boiler gauge. It may be correct, it may not. They are not very precise to begin with. It could be the relief, the expansion tank, or the pressure reducing valve. Pictures taken of the boiler and close components would be helpful. You may need a pro. If you take it on yourself, make sure you get the correct components.
  • T2
    T2 Member Posts: 4
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    Thanks!

    Yeah, I planned on picking up a reduction valve as well just to be sure. Ill install both and if that doesn't work ill check the expansion tank. Thanks!
  • Eric_32
    Eric_32 Member Posts: 267
    edited March 2011
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    Before doing anything

    go buy yourself a pressure gauge that has a hose thread adaptor, and screw it on a hose bib/ draw off/ boiler drain, and confirm the pressure in the boiler. If that new gauge is showing the same as your boiler gauge, why buy parts for nothing. And this way if your draining the boiler for the prv, you can change that gauge as well.

    My bet is your expanion tank is water logged. PRV's don't start leaking on their own unless they are bumped by someone, or there's excess pressure in the system.  
  • Robert_25
    Robert_25 Member Posts: 530
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    tankless coil

    Does the boiler have a tankless coil in use?  A pinhole in the coil will pop the pressure relief...if no tankless is installed, than disregard.
  • billtwocase
    billtwocase Member Posts: 2,385
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    sounds like

    expansion tank is full, or failed bladder extrol type tank. I doubt it is a feed valve or tankless coil. Something is very slowly raising the pressure when it is heating water, and that would be an expansion problem.  Pics please
  • meplumber
    meplumber Member Posts: 678
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    95% of the time it is a waterlog expansion tank.

    If it is a bladder type Extrol tank, the tap the bottom of the tank.  If it sounds hollow it is ok, if not it, the bladder has failed and needs to be changed.  If it is an older style expansion tank, then drain it.



    I also change the relief valve when I change a bladder extrol.  This is one of the most important safety devices in the system and is an inexpensive changeout for safety's sake.
  • T2
    T2 Member Posts: 4
    edited March 2011
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    Changed PRV today.

    A buddy, (journeyman plumber) and I changed the PRV today. Everything went great! Only thing is, the pressure is reading like 20 when cold and 26 when hot... Whoa!! The PRV is set at 12 PSI, and the releif valve isn't purging water, which was working fine before. I bled the system etc. The expansion tanks dont seem to be water logged, the only thing i can thing of is that maybe the guage was knocked out during the process... Is this possible???? It didnt seem to be off before... I guess the only real answer is a threaded guage... Thanks for all of the responses!



    EDIT: did a little research... Relief valve doesnt open until 30 PSI. Mayeb I'm alright, Ill have to check it in the morning before I turn the thermostat up.
  • Eric_32
    Eric_32 Member Posts: 267
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    little too much pressure there...

    26 PSI is too much pressure in the system when it's hot. If the expansion tank was working correctly the pressure in the boiler wouldn't move as it's heated.



    Sounds like it's full. If it's a bladder type tank, when you unscrew it you can add a 1/2" threaded ball valve with a drain on the side of it. Now in the future you can isolate the expansion tank and pull it out and back in in 5-minutes without draining the system down. You can open up the drain (on the ball valve) while the valve is off to relieve the pressure on the tank to check the air pressure in the tank as well.
  • T2
    T2 Member Posts: 4
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    Thanks!!

    Thanks for your help everyone!! I have been busy all week at work trying to get a house ready for the seamfillers, so the furnace took a backseat for a couple of days. I just drained the expansion tank and put it back on. It is a bladder type, and when I fired up the furnace the pressure went up a bit, it is running at about 16 psi, a little high yet so I think i may try a new tank. But, then again, who knows how accurate my guage is. Ill try and borrow one from a plumber at work tomorrow. I would love to see 12 psi!! Thanks again for all of your help!! Any more suggestions?
  • Ironman
    Ironman Member Posts: 7,378
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    A Bladder Tank...

    Never needs draining; that's the purpose of the bladder. Was there water at the schrader valve on the air side? If so, the bladder is ruptured and the tank needs replacing. If not, the air side must be charged to 12psi with no pressure on the water side.



    Your fill valve can be adjusted by turning the stem in for more pressure, out for less. Loosen the cap or lock nut first. You should have 12psi cold for a two story house and 18psi cold for a three story.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
This discussion has been closed.