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Vaporstat test problem??

I got a new vaporstat and am in the process of putting it in. No need for heat now in August but the vaporstat instructions say you can test it by reducing the set point through a range greater than the differential at which point the made contact should break. It doesn’t seem to be working and I hope I just am misunderstanding the instructions.

What I think it should be is...If I start with my set point at 16oz (range is 0-16) and gradually turn it to 0 oz, my R-B contact should change from make to break at some point. It is not working. The R-B contact stays at make through the whole range. Ive done this for a few differential amounts from 2oz - 8oz with the same result.

Am I doing something wrong or did I get a dud vaporstat?

Comments

  • gerry gillgerry gill Posts: 2,951Member
    Most of the time the new vaporstats don’t even work. I have to put on a test rig and play with the calibration screw to get them to work. I hope Honeywell’s missiles work better than their heating products..lol
    gwgillplumbingandheating.com

    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • FredFred Posts: 7,907Member
    If you bought the right Vaporstat, it should break (based on your settings) at 16 ounces and make at anything below that. What model Vaporstat did you buy? It should be Honeywell L408J1009
  • trivetmantrivetman Posts: 37Member
    Yes that is the model number.
    Honeywell L408J1009

    I think you mean it should break when differential is 16 as I am starting my test with the set at 16. Likewise If I understand this test right, when I set the differential to 8 it should break when the set is at 8 or less. It is not doing this. Maybe I have one of the duds
  • JUGHNEJUGHNE Posts: 5,778Member
    Are you trying to test this connected to nothing?
    I believe you have to have some pressure applied to it.
  • trivetmantrivetman Posts: 37Member
    It does not have any pressure applied to it. The instructions do not say the test needs to be done under pressure. If it needs some pressure above the room pressure to perform the test than that explains why its not working.
  • neilcneilc Posts: 680Member
    with no boiler pressure on the vaporstat, it should be a made switch, calling the boiler on,
    when the boiler pressure hits your cutout, or cutin plus differential, the stat (switch) should open and stop the boiler,
    your test should be that you turn the main down till the switch opens(this at no boiler pressure, or "on the bench"),
  • trivetmantrivetman Posts: 37Member
    And if the switch stays closed when the main set is turned all the way to zero with no boiler pressure?
  • EBEBRATT-EdEBEBRATT-Ed Posts: 5,914Member
    @trivetman

    You can't test any pressure control without it being connected to a pressure source. You have to use low pressure to test a vaporstat.

    How can you expect a control to work without any pressure?





  • trivetmantrivetman Posts: 37Member
    > @EBEBRATT-Ed said:
    > @trivetman
    >
    > You can't test any pressure control without it being connected to a pressure source. You have to use low pressure to test a vaporstat.
    >
    > How can you expect a control to work without any pressure?

    I’m just trying to follow the opaque (to me) test instructions in the manual, which don’t say anything about needing boiler pressure. I would not have thought to test like that if it wasn’t in the instructions. I figured I was probably doing something wrong which is why I posted. I’ll fire it up tomorrow to do a test with some boiler pressure.
  • neilcneilc Posts: 680Member
    trivetman said:

    And if the switch stays closed when the main set is turned all the way to zero with no boiler pressure?

    in my head it should open, but as others have said, these things need calibrating at times,
    or possibly some minimal base pressure to trip that switch.

    your wired in series with the other pressuretrol(s),
    correct ?
  • trivetmantrivetman Posts: 37Member
    > your wired in series with the other pressuretrol(s),
    > correct ?

    Yes I did. Set a cross on top of a pigtail with the 0-3 gauge, v-stat, and pressuretrol wired in series connected to the 3 outlets of the cross
  • SteamheadSteamhead Posts: 13,117Member
    edited September 1
    Here's the manual:

    https://customer.honeywell.com/resources/Techlit/TechLitDocuments/65-0000s/65-0287.pdf

    On page 6, under "If a Controller Seems to Operate Improperly"

    4. Lower the setpoint of the controller (simulating a
    pressure increase) through a range greater than the
    differential. The switch should either make or break,
    depending on the model of the controller. (See Table 1.)
    If it makes, the ohmmeter will read zero; if it breaks, the
    ohmmeter will read infinity.
    5. Raise the setpoint of the controller (simulating a
    pressure decrease) through a range greater than the
    differential. The switch should break or make, just the
    opposite of the result in step 4.

    So, if we set the differential to 8 ounces, and turn the Main scale down to less than 8 ounces, the switch should operate.

    I tried this on a Vaporstat that @Gordo tested, and the switch did not operate until I turned the Main down to 2 ounces. But the unit tested OK. Interesting................
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    https://heatinghelp.com/find-a-contractor/detail/all-steamed-up-inc
  • mikeg2015mikeg2015 Posts: 837Member
    Mine seemed off compared to my low range gauge last heating season. I bought a manual pump bulb, a barb Tee fitting and I plan on testing and calibrating it with a manometer.
  • Jamie HallJamie Hall Posts: 10,644Member
    It's worth remembering that these things are microswitches, which have a very definite built in force difference between the two states. With no pressure on the diaphragm, it is possible that they may not transition even with the indicator set at 0; further, as @Steamhead mentioned, the transition pressure may not be the same as it would be with pressure on the diaphragm.

    So, as has been said, the only really reliable way to test them, never mind calibrate them, is with a low pressure source and an accurate gauge.

    I might also add -- be sure that you are using the correct terminals on the switch. The model you reference has both make on rise and break on rise contacts. You want the break on rise contacts.
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
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