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abeatty44 Member Posts: 1

First time here, so please excuse my lack of knowledge. I fired up my boiler for the first time a week or so ago and shortly after noticed that the pressure relief valve was leaking a steady drip of water. I replaced the pressure relief valve, but the leak persisted. Having done some research, I am thinking the next step is to replace the expansion tank. Before doing so I was hoping I could get some clarity on doing so.

First of all when i tap the expansion tank it does not feel full. Also I tested the valve on the bottom of it and no water came out, does this mean the expansion tank is still good or could it still be the cause?

The pressure gauge on the side of the boiler reads 12psi (see photo), should I assume that this means the expansion tank should be at 12psi also?

I just tested the expansion tank and the pressure was about 13psi
. Feels warm at the top and cold at the bottom which I assume is expected.

If the expansion tank needs to be replaced, the current one is a Watts ET-60 which I believe is 6.6 gallons, my local hardware has none of the same make, but has a 4.4 or 7.6 gallon Amtrol tank. Should I assume that the 7.6 gallon one would be more suitable?

lastly, in the last photo, I circled in yellow the two valves that are either side of the expansion tank. Are these the only two valves that I need to turn off before removing the expansion tank (In addition to turning off the boiler). I assume so but ask because there are about 10 valve handles incase they all need to be switched off.

Any help is greatly appreciated.




  • hot_rod
    hot_rod Member Posts: 22,261
    You would need to either remove the tank or drain off the system pressure to read the true air charge in the tank. With an isolation valve above the tank that helps ease the procedure.

    The valve and the incoming fill valve need to be turned off, then loosen the tank carefully and put a bucket or towels below as water will come out of it until the pressure is released from the water side of the diaphram.

    If you do completely remove it they can be surprisingly heavy when full of water, many have been dropped.

    Does the pressure stay put at 12- 15 when the boiler is not firing? If not that tan colored fill valve could be leaking pressure into the system, it should have a valve in front of it also to isolate it out of the equation.

    The tank is not in an ideal location if the arrow on the grey Taco pump is point towards it, pumping towards the tank, but if it has worked in the past....
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    Keep in mind if that tank is waterlogged it will be VERY HEAVY, and you won't have the correct body position to hold it and could possibly hurt yourself.
    I would put some blocking under the tank so you can unspin it & it can't drop.
    I'd also switch the tee, take out the valve and replace it with a Webstone exp. tank valve.

    There was an error rendering this rich post.

    EBEBRATT-Ed Member Posts: 15,628
    Yeah, be careful taking the tank off if waterlogged. For some reason they are difficult to get a grip on and you can't tell when the last pipe thread is.

    I dropped one once lucky to still have all my toes
  • GroundUp
    GroundUp Member Posts: 1,926
    Just a thought, but having seen dozens of those pressure gauges stuck in the past, I need to ask. Were you able to watch the gauge move when you drained down to swap the relief? There is a possibility that the auto-feed has taken a crap and is feeding too much pressure to the system, flirting with the relief.

    Secondly, is this by any chance a Watts relief? I'm not sure why, but the last dozen or so I've gotten new have had a slow leak right out of the box even at 12 psi
  • ChrisJ
    ChrisJ Member Posts: 15,784
    Agree with the others regarding the weight.

    I watched two friends try to change one once that was mounted upside down with the connection at the bottom. They couldn't isolate the tank so they decided one would spin the tank off and when he removes it the other would stick his finger over the hole to try and minimize the water loss.

    The guy spun the tank off and lifted it about an inch and the other stuck his finger over the hole, but the first guy couldn't hold the tank so he put it back down.

    "YOU'RE ON MY FINGA!!!!!!!!!"

    The Brooklyn accent made it that much better. :D

    Be careful and take your time.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • CTOilHeat
    CTOilHeat Member Posts: 56
    I usually drill out the bottom of these tanks and let it drain out if I have any doubts about being able to manage it's weight.

    Takes a few minutes to drain but worth it.