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What's the best pressure relief valve for my system

acl10
acl10 Member Posts: 349
edited March 2018 in Strictly Steam
Whats the best pressure relief valve for my system. I currently have this Conbraco 13-211 3/4 size valve and its leaking. The guy in the hardware store gave it to me a few years ago. Is that the proper valve for my steam boiler? I want to replace it. Is the valve supposed to be 15psi
like this one Apollo Valve 13-211 Series Bronze Safety Relief Valve, ASME Steam, 15 psi Set Pressure, 3/4" NPT Male x Female
or 5psi like this one
Apollo Valve 13-211 Series Bronze Safety Relief Valve, ASME Steam, 5 psi Set Pressure, 3/4" NPT Male x Female

Comments

  • acl10
    acl10 Member Posts: 349
    According to the co its the 15psi. Is apollo tthe best company or should I go with another brand and or different pressure?
  • JohnNY
    JohnNY Member Posts: 2,761
    You've got a residential steam heating system. Any 15 PSI relief valve by any manufacturer will be fine. Don't over-think it. It's a safety device that will likely never open and not an operating control that will cycle with each call for heat.
    Contact John "JohnNY" Cataneo, Master Plumber
    in New York
    in New Jersey
    for Consulting Work
    or take his class.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 10,328
    But the most important thing other that the 15 psi pressure is to make sure the safety valves btu rating exceeds the boiler btu rating.
  • acl10
    acl10 Member Posts: 349
    https://www.amazon.com/gp/product/B002KU0WV0/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

    I dont see any BTU rating on the valve.
    My boiler is
    Enerjet 262,500 BTU input, 214,000 output
  • FinishGuy
    FinishGuy Member Posts: 31
    Easily found this for the new valve you linked to:

    http://cdn.conbraco.com/apollovalves/products/documents/SS_13-100_200_1064.pdf

    Both your old failing valve and the new valve you have the questions about have the same rating at 475 lbs. steam per hour.

    Not surprising given they are essentially the same #15 3/4” valve.

    There are more than a few online calculators and conversion formulas:

    (475 divided by 34.5) x 33,472 = about 461,000 BTU max. Rating

    461 > 262

    How did I do, @EBEBRATT-Ed?
    1916 two-family, now condo. Top floor. 970 sq. ft. of ‘well ventilated’ space. One-pipe, parallel flow, gas fired steam heat. 27’ of 2” main (un-insulated) vented via Gorton #2. 27’ 1 1/2” dry return (un-insulated) vented by Dole #5. 7 HB Smith Princess 2 col. radiators (38” tall) & 1 ARCo 30s era thin-tube 6 x 8 sec. (32” tall) = total radiator EDR 244. Using Maid-o-Mist radiator vents, sized by calc. & 14 winters tinkering. 1980 HB Smith G210-S-5 rated output 120,000 btu, poor near boiler piping.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 10,328
    @FinishGuy , I would say fine. I usually take the valve rating of 475 lb of steam x 1000 (=btus/lb of steam)

    =475 x 1000=475,000
  • FinishGuy
    FinishGuy Member Posts: 31
    edited March 2018
    Cool. Thank you, sir.

    The formula I found and used went by way of horsepower first, then btu. Ought to have noted that.

    So what does this value, the PRV’s capacity, represent? Its over all robustness? This is essentially an energy rating over time, correct?
    1916 two-family, now condo. Top floor. 970 sq. ft. of ‘well ventilated’ space. One-pipe, parallel flow, gas fired steam heat. 27’ of 2” main (un-insulated) vented via Gorton #2. 27’ 1 1/2” dry return (un-insulated) vented by Dole #5. 7 HB Smith Princess 2 col. radiators (38” tall) & 1 ARCo 30s era thin-tube 6 x 8 sec. (32” tall) = total radiator EDR 244. Using Maid-o-Mist radiator vents, sized by calc. & 14 winters tinkering. 1980 HB Smith G210-S-5 rated output 120,000 btu, poor near boiler piping.
  • AnthraciteEnergetics
    AnthraciteEnergetics Member Posts: 77
    Capacity is the amount of fluid it can discharge while keeping the vessel below the design relief valve pressure. For steam, 1 lb/h is about 1000 BTU/h (1 MBH) The valve rating should be higher than the amount of steam you could make. My boiler is 98 MBH (98 lb/h of steam) output and came with a 500 lb/h valve on it.