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Manometer for measuring boiler pressure

I just had an "brainstorm". I have a manometer I use to check the gas valve outlet pressure. I do not leave it connected.

I just wondered if anyone has ever use this type of device to check how high the steam pressure goes. Then it would be easier to determine which really low pressure gauge to get, if someone wanted to get something like a Magnehelic.

Comments

  • KC_Jones
    KC_Jones Member Posts: 5,705
    edited October 2022
    @ChrisJ @ethicalpaul have Magnehelic installed and I have one on the shelf waiting for me to get the time to hook it up.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
    ChrisJ
  • ethicalpaul
    ethicalpaul Member Posts: 5,617
    edited October 2022
    KC means the gauges.

    as for a manometer, yes it would work fine but if your pressure goes higher than your meter, it will push water out the top.

    so I’d only use it for a fun experiment or put a valve on it for when it’s not attended.

    but you don’t really need it, just get a gauge that has a range of whatever psi you see.

    like if you have a 0-3psi gauge and you see it go to 1/2 psi then get a magnahelic with a range of like 20 inches of water column
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • ChrisJ
    ChrisJ Member Posts: 15,473
    https://youtu.be/hH36luC9GKU


    Connected directly into the boiler, no pigtail just an 18" tall 1/2" steel vertical pipe as an air gap.

    Air can't get out so steam can't get in.

    Pigtails cause issues when measuring pressure this low because of the weight of the water etc.
    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
  • neilc
    neilc Member Posts: 2,667
    I have clear(was) vinyl tube, on a hose end repair, attached to the boiler drain,
    the tube is long enough to reach up over pipe at the ceiling, and back down to about 6 inches to the floor for safety,
    I don't leave the drain open when I'm not there,
    measures inches of water above normal water line real well.
    known to beat dead horses
    ethicalpaul
  • mattmia2
    mattmia2 Member Posts: 9,459
    Dwyer makes some electronic gauges that have both high precision and a fairly wide range which I think could measure the tiny pressure of an open system venting and the possible 2 or 3 psig of a system with a presduretroll shutting down on pressure.
  • mattmia2
    mattmia2 Member Posts: 9,459
    Thinking some more, couldn't a thermostat attached to the hx below the water line act as a tertiary protection against dry firing?
  • ethicalpaul
    ethicalpaul Member Posts: 5,617
    edited October 2022
    Sure could. Like the thermal fuse they put in the windings of mixer motors (and probably lots of other motors)
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • ChrisJ
    ChrisJ Member Posts: 15,473
    A Magnehelic is safe up to something like 16 or 20 psig.

    It'll only register up to a few inches but won't be damaged by going higher 
    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
    mattmia2ethicalpaulMikeAmann
  • ethicalpaul
    ethicalpaul Member Posts: 5,617
    ChrisJ said:

    A Magnehelic is safe up to something like 16 or 20 psig.

    It'll only register up to a few inches but won't be damaged by going higher 

    Yeah and the newer ones have a blowout plug that will...blow out if you over-pressurize it
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 980
    @mattmia2 Connect the dots for me...how does your comment about a thermostat have something to do with using a manometer to check boiler pressure?

    @neilc That's quite a MANometer! LOL

  • mattmia2
    mattmia2 Member Posts: 9,459
    I think it came from we control a steam boiler on pressure(and a failed pressure control could damage your measuring device) and then we control it with a low water cutout which both are somewhat complex and have rather common failure modes that can cause them to fail closed and that a block of cast iron full of water won't get hotter than the water so a thermostat (or thermal fuse as @ethicalpaul suggested) is a lot less prone to failing to shut the burner down.
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 980
    Thanks
  • GBC_illinois
    GBC_illinois Member Posts: 97

    I just had an "brainstorm". I have a manometer I use to check the gas valve outlet pressure. I do not leave it connected.

    I just wondered if anyone has ever use this type of device to check how high the steam pressure goes. Then it would be easier to determine which really low pressure gauge to get, if someone wanted to get something like a Magnehelic.

    I have done this, because even though I have a low pressure gauge (32" WC), it acts up and I don't trust it. To make a simple manometer, I connected a silicone tube to the sight glass drain. As long as you are running at low pressures, like under 1.5 psi, its easy. Here are some pics of my setup. Note that the marks I made are in oz of pressure, not inches of water.









    109A_5SteamFTW
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 980
    I just saw your comment, sorry for not looking sooner.

    Nice.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,335
    The old garden hose trick :)
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,849
    ChrisJ said:

    Air can't get out so steam can't get in.

    Maybe I'm not understanding what you described, but in a ½" pipe, the steam could rise right through the air, couldn't it?
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
    ethicalpaul
  • ChrisJ
    ChrisJ Member Posts: 15,473

    ChrisJ said:

    Air can't get out so steam can't get in.

    Maybe I'm not understanding what you described, but in a ½" pipe, the steam could rise right through the air, couldn't it?
    In order for steam to rise through the air some air would need to be pushed out.
    The air will not push out as the entire opening of the 1/2" pipe is exposed to the same pressure.

    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
  • 109A_5
    109A_5 Member Posts: 1,344
    Hello @Hap_Hazzard,

    ChrisJ said:

    Air can't get out so steam can't get in.

    Maybe I'm not understanding what you described, but in a ½" pipe, the steam could rise right through the air, couldn't it?
    Seems maybe a bit counter intuitive. I have a 12" long 1/4" pipe (above the boiler jacket, out of the top of the boiler) with trapped air. About 8" up I can hold my fingers on it for the whole boiler run. 8" up on the 2" Steam main I will get burned. So yes it does seem where air is stagnant (or trapped) Steam won't go. I suspect where the Steam meats the air it cools enough that it then becomes condensate and propagates no more (as Steam). Clear tubing experiments are fun, don't get burned.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    ChrisJ