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pressure problem

joe_14 Member Posts: 138
iam having a strange problem with pressure on this system,the problem has been going on for a couple of years. whats been happing is a couple of years ago i replaced the extrol 30 with an extrol 60.ran fine for a year. then the relief would start to drip again and the pressure when the burner was running would creep up to 30lbs. iam running the system at 18 psi because of an air handler in the attic which heats the upstairs bedrooms. there is an air handler in the basement for the first floor and an indrect water heater. i did pump up the extrol tank to match my system fill pressure. the second time i replaced the extrol 60 with another one. things seemed fine. yesterday i get a call from customer the system is doing the same thing. i added an extrol 30 with the 60. now when the burner runs the pressure stays at 20psi but when the burner shuts down the psi drops back to 14psi as the boiler cools. the system does have antifreeze in it.but i have many other systems with antifreeze in them an have no problem. the boiler is fired at 1.25 gph.the boiler is a wbv-o4 peerless.not a large water content system.

any help and wisdom you can give me would be greatly appreciated.

thanks joe.g.


  • S Davis
    S Davis Member Posts: 491

    Is your pump on the supply or return side of the boiler, and where is the expansion tank in relation to the pump?

    S Davis
  • joe_14
    joe_14 Member Posts: 138

    boiler is pumping away,expansion tank is piped into bottom of air scoop

  • S Davis
    S Davis Member Posts: 491
    Fill Line

    What about the boiler fill, I had problems on a system where when the pump turned on it caused a slite reduction in pressure and the boiler fill would feed a little water into the system, it could take a while to fill enough to cause a problem.
    The reason I asked about the pump is I have seen systems with the pump on the return that would increese the presure in the boiler when it turned on and cause the T&P to drip.
    Another thought have you tried replacing the T&P valve? If it has been worked alot the spring could be getting weak.

    S Davis
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