boiler supply

Discussion in 'HVAC Heating & Cooling' started by jpiazza, May 27, 2008.

  1. jpiazza

    jpiazza New Member

    Messages:
    18
    Hi. I had to reroute the supply feed for my boiler. On the line is a shutoff, a pressure reducer valve, what looks like a pressure relief valve and another shut-off. The manual for the boiler has all these parts except there is a check valve in the place of the pressure relief valve. Should I swap out the pressure relief for the check valve like the manual has it or should I just add the check valve after the first shut off and leave the rest in the order that it was in? Thanks in advance.
  2. cattledog

    cattledog New Member

    Messages:
    42
    Location:
    Portland, Oregon
    Jack--

    Are you sure it is a pressure relief valve and not a back flow preventer which is also designed to vent water.

    I don't know if your boiler is steam or hot water, but for hot water applications many (all?) codes require a back flow preventer in the incoming water line. I don't know the requirements for steam boilers, but I would expect its similar.

    If you don't already have a back flow preventer, you may want to consider adding one instead of a simple check valve.
  3. jpiazza

    jpiazza New Member

    Messages:
    18
    Thanks for the response. I'm not sure really what it is. It does have a discharge port on the bottom. It is a Bell and Gossett and there is a No 8 stamped on it. So this would be in place of the check valve? Thanks.
  4. jpiazza

    jpiazza New Member

    Messages:
    18
    By the way it is a hot water system. Also the valve is red, dome shaped and has a hook shaped lever at the top to open the valve. It doesn't look like any backflow preventer that I have been looking at online.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,049
    Location:
    Cave Creek, Arizona
    valve

    The generic drawing shows an engineer's concept of how it goes. He usually doesn't show the relief valve there because he thinks they are always on the boiler itself. He probably doesn't know that the reducing valve has an internal check valve capabilities. Do not eliminate the relief valve unless you replace it elsewhere or there is one on the boiler. You do not need a check valve for the automatic fill side unless your municipality requires it. You do want a check valve on the manual bypass, if you have one, to prevent water loss if the house pressure drops and the manual valve is opened.
  6. jpiazza

    jpiazza New Member

    Messages:
    18
    Great thanks hj. I have the relief valve on the boiler already so I can lose this one. I will also check today to see if I need a check valve on the supply side here in Chicago. Thanks again.
  7. BigLou

    BigLou New Member

    Messages:
    138
    you might not want to remove that it sounds like the fast fill valve, it automatically adds water to your system if the pressure drops below a given set point.

    Lou
  8. jpiazza

    jpiazza New Member

    Messages:
    18
    Thanks Lou. Also on the supply line is a B&G fb-38 which I believe is serving that purpose. I haven't been able to find out if I need a check valve in Chicago yet if any one knows.
  9. jpiazza

    jpiazza New Member

    Messages:
    18
    In fact I need a strainer screen for that B&G. Does anyone know where I can get that?
  10. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,049
    Location:
    Cave Creek, Arizona
    check

    We never used one when I was there.
  11. Furd

    Furd Engineer

    Messages:
    446
    Location:
    Wet side of Washington State
    The Bell & Gossett combination pressure reducing valve and pressure relief valve assembly is commonly used in closed-loop hydronic systems that have steam-to-water heat exchangers. Most of these are in commercial or industrial installations.

    Forty-plus years ago this combination assembly was also commonly used on residential hydronic systems. Sometimes the boiler-mounted safety valve was not installed in the mistaken belief that the B&G relief valve served a similar purpose.

    For at least the last thirty years (and probably longer) an ASME steam or BTU rated safety valve has been REQUIRED to be mounted directly on the boiler or with as short a nipple and one ninety as practicable. The addition of the B&G relief valve on such a system is not needed.

    [​IMG]
  12. jpiazza

    jpiazza New Member

    Messages:
    18
    Furd, That picture is what I have it is just separated by a nipple. I think the pressure reducer was upgraded with the boiler and they kept the old pressure valve which is red and looks older. As I said before there is a relief valve on the boiler itself. So in the end I will be going shut-off, pressure reducer valve and shut-off. Thanks for all the responses.
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