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Hydronic system

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Snoochie
Snoochie Member Posts: 9

Hi I installed a new gas hydronic system 133,000btu.system is building up pressure.I drain system to 12lb bled the 2 zones.2 days later same thing turned off feeder to system check ok. replaced feeder and went to a 60lb expansion tank. Next day same condition system building up pressure and go off on relief valve. Any suggestions?

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  • ScottSecor
    ScottSecor Member Posts: 863
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    Is there a tankless coil or insirect hot water tank that may have a pinhole leak?

    Are you certain the feedwater vavle is working one hundred percent (if soldered was it possibly overheated)?

    Any chance you took care of the problem but the gauge is inaccurate?

    Any chance you took care of the problem but the relief valve has blown off so many times that it no longer pops at 30 psi and is now relieving at say 20 psi?

  • Snoochie
    Snoochie Member Posts: 9
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    After several new parts I had system operating and it build up to 20lbs.It's seems to build up at night . I even turned off feeder and system was at 20lbs and then went to 25 lbs with the feeder off. The relief valve is operating normally..

  • ScottSecor
    ScottSecor Member Posts: 863
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    Any chance the new expanstion tank was not pre-charged to 12psi? Is it a bladder type (Extrol 60 for example)?

  • Snoochie
    Snoochie Member Posts: 9
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    Yes I also checked that.. And I was advised that was the same problem with the old boiler toomuch pressure..and the 3 parts where replace relief,tank and feeder.

  • ScottSecor
    ScottSecor Member Posts: 863
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    Is there a tankless coil or indirect hot water tank?

    Are you certain the feedwater valve actually stops flow of water to the boiler?

    In other words is there any possiblilty there is another source of water being introduced to the boiler?

    Please post a few photos, sometimes a photo helps everyone learn.

  • Snoochie
    Snoochie Member Posts: 9
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    The water feeder was installed above the circlater pump and 3 speed pump any chance that's pulling water from feeder. There's no coil or storage tank. Looked around house and crawl space no other water feed to system.

  • ScottSecor
    ScottSecor Member Posts: 863
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    I tried to look closeuly at your phots and was trying to play detective.

    Ideally the pump would not be on the return but on the supply - after the expansion tank/separator. But I'm not convinced this is your problem.

    I notice the Nibco valve on the right side of your photo that I assume is the feedwater valve (near the zone valve marked "2". This particular valve has a drip of solder on the bottom of the valve body. Is there any chance this valve was overheated when it was installed and is not shutting off the flow completely?

    I did not see a pressure reducing valve, where is it?

    You mentioned a 60lb expansion tank. Not sure what you meant by that, but the tank in your photos is an Extrol 30 that should have a factory charge of 12psi.

  • Snoochie
    Snoochie Member Posts: 9
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    The feeder is at top and I didn't take any photos of the new 60lb expansion tank. would a small water leak in system expand and have a leak when hot and close when cooled contribute to problem?

  • yellowdog
    yellowdog Member Posts: 157
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    you need to explain what a "60lb expansion tank" is. hopefully that is not what you have the pressure in the tank set at.

  • Snoochie
    Snoochie Member Posts: 9
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    i changed the 30lb tank to a 60 lb expansion tank which was set at 12lbs.I was running out of ideas to eliminate the pressure problem. I installed a 60lb tank .which didn't help. This is a mystery of the increasing pressure that I'm out of solutions.. Maybe something I've over looked

  • GGross
    GGross Member Posts: 1,072
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    I think you mean you changed out a number 30 extrol expansion tank, with a number 60 extrol expansion tank. 30lb and 60lb mean something different.

    Can you send a couple more pics of the water feeder, as it is installed and how it ties into the hydronic system. Currently in the pictures it looks like it is still open to the boiler system, if it is not working correctly it could be over pressurizing your system

  • Snoochie
    Snoochie Member Posts: 9
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    Yes a #30 fora#60 tank..I don't have more pictures but the water feeder is piped into the return above the pump.

  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,060
    edited March 2023
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    We see your situation often here and I don't think we've ever arrived at a solution. Scott mentioned that the pump is in the wrong location - should be pumping away from the x-tank.

    How long has this system been up and running? Have you spoken to the installer about the problem?

    I've noticed that Spirotherm air separators can block the connection of the x-tank to the system. I would remove the x-tank and see if there's any debris at the bottom of the Spirotherm unit. I would even go so far as to remove the top of the Spirotherm to check for any blockages. Maybe you can even do that before you remove the x-tank.

    Too bad that gas pipe goes right in front of where you want to work. Kind of gets in the way.

    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
    GGrosskcopp
  • Snoochie
    Snoochie Member Posts: 9
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    That was all checked the removal of the c tank and spiro vent disconnected to check internal all checked out good. This problem was with the old system also. Unit eas installed Nov 2022.. the old boiler was installed back in the 80's

  • GGross
    GGross Member Posts: 1,072
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    I would leave the water feed valve closed until you figure it out. No point in having it open while the pressure is rising. I like to leave those valves shut off anyway so we know if a leak develops

    davidd
  • hot_rod
    hot_rod Member Posts: 22,271
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    every time the circ kicks on it drops pressure at the inlet, could be 4, 5 psi or more. That could cause the fill valve to kick on and add more pressure, so you end above the static fill pressure when the circ shuts off


    I'd move the Expansion

    tank to this 1/2" copper fill line

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    SnoochieAlan (California Radiant) Forbesdavidd
  • Snoochie
    Snoochie Member Posts: 9
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    I'll try relocating the x tank..Thank for all for the help greatly appreciated .