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pressure reducer valve

Samparsippany Member Posts: 2
I have a peerless boiler and the presser relief valve was leaking water (30 psi) for few days. I was able to change the pressure relief valve and expansion tank to see if there was an issue. Water is still leaking through the pressure relief valve after I changed them. I have a pressure reducer valve before the boiler (12 psi B&G Model FB 38) and I tried to adjust the pressure on the pressure reducer valve but pressure still over 30 psi. Would it be correct to say that pressure reducer valve needs to be replaced? Any other suggestions?


  • STEVEusaPA
    STEVEusaPA Member Posts: 5,787
    edited June 2020
    When you say pressure reducer, do you mean the water feed?
    First, valve off the water feed, make sure system is purged of all air.
    Next would be to isolate (valve off or drop pressure, drain) system and check the charge of the expansion tank.
    If it still happens, and the shut off is actually holding, valve off the indirect (make sure the circulator is off), run a heat cycle, heat up the boiler to high limit.
    These are the simple ways a homeowner can check by process of elimination.
    It's fairly common for the water feed to get some sediment in there that prevents its closing and allows water to seep by.
    Depending on the type of feed valve, you can probably isolate it, and either clean it out, or replace it.
    If you replace it, put valves on both sides, add a backflow preventer (code), and maybe a Webstone expansion tank valve for further easy checking/maintenance/replacement.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 3,658
    edited June 2020
    There is another possibility. The water heater looks like an indirect. if the heat exchanger inside the water heater has a pin hole... the pressure will rise in the boiler.

    Your picture does not shoe the boiler piping to the water heater. if there are isolation valves then the test will be easier. If there are no valves on the boiler feed and return then you can test by shutting off the cold water feed to the water heater.

    @STEVEusaPA test for the FB 38 failure would be completed by closing valve marked C2 just past the FB-38. Then drain off some pressure to say 15psi. If the Pressure does not rise to 30 psi, but just stays between 12 - 20 psi then the FB 38 is passing.

    if the pressure begins to increase again, then the FB -38 is not the cause. Now you need to close the valves marked C1 and C2. This will isolate the water heater from the boiler. If no pressure increase to 30, then the tank is bad.

    If your boiler piping is not equipped with C1 & C2 valves (Must have both), then you can do the test with the C1 valve. But you MUST have no cross connection of the potable water system. To ensure this will not effect the test, leave a hot water tap open on the first floor. This means you have no hot water for the duration of the test.

    How long does it take for the pressure relief valve to start passing aft the boiler pressure is set at operating pressure? (About 12 to 18 psi), that is how long you need to do the test. Don't be surprised if you have both problems. It has happened
    Edward Young
    Retired HVAC Contractor from So. Jersey.
    Services first oil burner at age 16
    P/T trainer for EH-CC.org

  • Samparsippany
    Samparsippany Member Posts: 2

    Thank you. I do have C1 and C2 valves. When I first closed the C2 there was no change in the pressure in the boiler and pressure relief valve (30 PSI) was still leaking. Once I closed the C1, pressure relief valve stopped leaking and pressure stayed exactly at 30 psi. After opening C1 , within 30 seconds pressure relief valve starts passing water. Based on this would it be correct to say that indirect water heater’s (Bock 40CT, at least 10 years old) heat exchanger pipe has a hole? Time for new water heater?

  • Jamie Hall
    Jamie Hall Member Posts: 19,444
    Sure sounds like it to me.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England