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Pressure gauge and pressure relief valve question

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by stoney28, Aug 6, 2013.

  1. stoney28

    stoney28 Member

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    My boiler had sprung a leak last year and I got it welded. This spring it began to leak again. I've since discovered that the pressure gauge and pressure relief valve needed replacing. I've got both of the new ones in, and now I'm having a problem.

    I'm trying to cold test the latest weld to see if there is a leak before I fire up the boiler this fall. According to the pressure gauge I'm at about 7psi (while it is filling). I'm not sure when the actual furnace is full so I've turned on the circulator to get some of the water from the storage tank into the boiler. When I turned on the circulator the new pressure relief valve blew (its set for 25psi, and that is the lowest it can be set for. I turned off the water and the pressure gauge reads 0, but while the circulator is on it blows the relief valve. Pressure gauge and relief valve.jpg New pressure gauge.jpg

    What am I doing wrong?

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  2. TheMightyMoe

    TheMightyMoe Minister of Fire

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    That's a weird one...

    Are you bleeding air in anyway? (Other then just the air vent)

    Does your pump have a check valve built into it?

    Your pressure relief valve should be a set value (I believe) and not adjustable.

    Is your water pressure regulator working?
  3. stoney28

    stoney28 Member

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    I wasn't bleeding any air other than through the vent. After I turned off the water, but when the circulator was still running, there was air coming out of the pressure relief valve.

    I don't know if the pump has a check valve, how would I check for that?

    The pressure relief valve is adjustable, by turning it. It has little numbers on it to indicate what pressure its set to go off at. It was the only one I could find that would go as low as 25psi.

    How would I check the water pressure regulator?
  4. Fred61

    Fred61 Minister of Fire

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    I once had a pressure relief valve leak after bleeding air through it when filling a system. It turned out to be a ribbon of solder that that had been residing in the boiler that got into the seat/seal of the valve which was not allowing it to seal.
    Is it like blowing off, ie. high flow or just a slow to moderate flow?
  5. stoney28

    stoney28 Member

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    it was coming out like a faucet on about halfway.
  6. TheMightyMoe

    TheMightyMoe Minister of Fire

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    I'm not sure how your entire system works so it's hard to trouble shoot but...

    If you have a better place to bleed air when you fill it, I highly suggest that, typically you bleed from the highest point of the system / loop. The last thing you want in your system is air. You should be flushing from one end to another when filling so you get most the air out.

    When you turn on the water, the gauge on the boiler SHOULD equalize to whatever your incoming water pressure is / whatever your water regulator is set to.

    So if/when water pressure reachs 25PSI, the pressure relief valve should start gushing/blowing air, then if you turn off the water, the system should be pressurized to 24.9 ISH PSI. Assuming you have no leaks... To adjust the water pressure regulator, you turn it, one direction will be higher, one will lower, start low and work it up to where you want it.
    BoilerMan likes this.
  7. Fred61

    Fred61 Minister of Fire

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    I would remove it and check the seal and look for anything that might be hindering closure.
    TheMightyMoe likes this.
  8. maple1

    maple1 Minister of Fire

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    I can't see a circulator pump generating enough PSI to blow a relief valve?

    Sounds like your relief valve is open, somehow.
    TheMightyMoe likes this.
  9. hobbyheater

    hobbyheater Minister of Fire

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    Do you know the pressure of the water in the storage tank? High pressure in the storage could indicate that there is a leak in the DHW heat exchanger, domestic street pressure overpressuring storage.
  10. stoney28

    stoney28 Member

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    I don't have the boiler hooked to the hot water in the house. That was an "I'll get to that" that never happened.

    I'm changing the new pressure gauge for better one. I don't think the one I have is right. I think its possible that the pressure relief valve might be slightly off. It wouldn't take much of a turn to change even 5 pounds of pressure.
  11. heaterman

    heaterman Minister of Fire

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    Ditto. Turning on a circ will not pop the relief unless the system was right at the edge in the first place.
    One more reason to pump AWAY from the expansion tank and boiler .
  12. heaterman

    heaterman Minister of Fire

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    Are you sure you are using a relief valve suitable for a boiler? I'm not saying I've seen and know everything but I've never seen a boiler relief that was adjustable. The metal tage on the valve will have a btu rating on it whereas a standard relief for water pressure only will not.
  13. stoney28

    stoney28 Member

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    A guy in the shop that sells plumbing supplies recommended it to me after I told him what I needed. Here is a link to the company that makes the valve (the picture on the right looks like mine). http://www.cashacme.com/prod_relief_valves_fwc.php

    Here is the specifications pdf. http://www.cashacme.com/_images/pdf_downloads/products/relief_valves/fw_fwc/FW_FWC_Spec.pdf
    It says its adjustable from 25 to 175psi and good up to 210 F.

    I set up a new pressure/temperature gauge and the same thing happened. The new gauge reads 0 unless the I'm turning the water on. I drained part of the furnace earlier. I'm beginning to think this might be a problem of air escaping while I'm trying to refill the boiler with water.
  14. maple1

    maple1 Minister of Fire

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    If that relief valve is leaking at anything over 0 psi, there's something wrong with it.

    It actually sounds like something I would not use at all. The lower limit on it is about the max I would want on a boiler relief, if it was a bit out of spec you could see dangerously high pressures before it blows. And, it is not uncommon to see temps at or close to 210°, or even more than that, in a pressurized boiler. I would definitely get the right thing, this doesn't sound like it.
  15. stoney28

    stoney28 Member

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    I brought the valve back to the store I bought it at, and an older, more experienced worker told me that it was not the proper valve for what I needed, and they found a regular 30psi pressure relief valve. Installed now and boiler filled with water. The new weld, seems to be holding fine. I had the pressure up to 20psi cold, and no leaks. I've brought it back down and I'm thinking of firing it up just to make sure there are no more leaks when its at operating temperature/pressure.

    Thank you all for your help. :)
    hobbyheater likes this.
  16. stoney28

    stoney28 Member

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    I test fired the boiler today to check the weld. It started leaking again around 25psi. Does anyone know of other options I can explore to get this thing fixed? Last October some people mentioned Boiler Stop Leak. Would that damage the circulator pumps if I put it into the system? The leak is on the side of the boiler, but toward the upper rear. Is there an internal circulator in the EKO 40 that Stop Leak would damage? Or should I ask my friend who did the welding to cut out the offending section and weld a patch on there.

    On a side note, the guy who welded it said the plate was only about 1/8" thick. Is that normal for the EKO?

    Edit: My father suggested a boiler plug. Does anyone know anything about those?

    Edit 2: Or maybe a welding a plate of steel over the spot with the leak.
  17. 700renegade

    700renegade Member

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    exterior plate is 4mm on an EKO ( interior is 6mm ). math works out to 0.158" or 5/32". I'd like to know more about where it was leaking and why. Was it on a seam or middle of the sheet?
  18. TheMightyMoe

    TheMightyMoe Minister of Fire

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    A clean weld will require cutting/grinding/patching, and still isn't recommended, but sometimes its you gotta do what you gotta do.

    Why is your water pressure @ 25 PSI?
  19. stoney28

    stoney28 Member

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    The leak was on the plate, but there was a small L shaped spot there originally. It looked like a weld spot (drips of metal hardened in the L shape).

    The pressure was at 25psi because I had fired it up to test out the weld to see if it would hold. I'm pretty sure the manual said the EKO is meant to operate at 25psi and I could only get a pressure relief valve at 30psi.

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