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  • Steamer Thermostatic Trap

     olivero updated 2 years, 1 month ago 1 Member · 18 Posts
  • guest

    April 4, 2018 at 12:00 am

    Hey guys,


    I got A 36CGM16300  steamer which has a thermostatic trap on it, I’ve never dealt with these before so I am trying to figure out how they work, what they do and why its making a rattling sound every couple of minutes. I looked it up online and I can’t seem to find out if its bad, normal or signaling it needing changed.


    Anybody got an idea?

  • ectofix - Nashville

    April 4, 2018 at 5:31 pm

    Got a picture or part number of it?  Is it this one:

    Cleveland 20559 TRAP,THERMOSTATIC 1/4IN COMP X | Parts Town 


    It’s probably the one plumbed above the water line, right?

    That trap allows air to escape to prevent pressure build while air is displaced as water enters the boiler during initial fill.  Since the boiler is otherwise sealed, air would compress and build up pressure.  That trap is simply open when cold and closed after it gets hot.


    The boiler pressure should be at 0 psi when the boiler is cold and there’s an initial call for heat.  The boiler’s heat cycle is controlled by boiler pressure.  As the boiler heats to the point near steam temperature, the trap will close in response to the temperature rise.


    A trap that has failed closed will mess with you if you’re not familiar with its function.  In such a case, pressure will build during initial fill.  When the water probes sense water level for heating, a pressure switch would normally engage the heat cycle.  However, if air was trapped during fill, the pressure built up would have already satisfied the pressure switch.  Therefore the unit won’t heat.


    If it’s gotten noisy, maybe some scale got suspended in it and is messing with its works.  I would replace it right away.


    One additional note:  Check whatever tubing that’s connected to it to be sure it’s not becoming clogged.

  • olivero - Florida

    April 4, 2018 at 8:40 pm

    Hey Ectofix, That sure looks like the critter


    Cleveland 101207 TRAP,THRMO W/POL.SEAT 1/4MPTX1 | Parts Town 


    That’s the one


    Thank you. The steamer is definetley still working properly, haven’t gotten any complaints. It does it every couple of minutes for 1-3 seconds. It seems to be right after it adds water to the boiler, even if the water valve is on for a second or 2. Makes sense how it works, I guess it might just be making noise but still working, otherwise I would be seeing some problems right?


    Definitely going to replace it, just wondering if I have to worry about it.

  • fixbear - ADK NY

    April 4, 2018 at 8:51 pm

    It’s just a steam trap. It’s on the steam outlet line to return condensate back and prevent liquid hammer in the steam line. It’s no more than a float valve to prevent water in the steam line.  If you get water build-up in a steam line it can flash to steam suddenly creating a hammer effect. Makes a lot of noise.

  • olivero - Florida

    April 4, 2018 at 9:04 pm

    Got it. okay.


    But since its making this sound, do you think the part is completely defective or on its way out but still working?


    I guess either way its not VITAL to the units operation.

  • fixbear - ADK NY

    April 5, 2018 at 4:28 am

    Problably has minerals in it and can’t drain.  Awful small inlet. They use the Tee and reducer as a collection area.

  • olivero - Florida

    April 5, 2018 at 8:33 am

    Yeah. makes sense. I’ll just get it replaced.

  • guest

    April 6, 2018 at 1:26 pm

    There are several different kinds of steam traps. Depending on which one you have, rattling may be ok. The little barrel type that Cleveland uses, doesn’t make any noise. Larger bucket style traps are pretty quiet also. They are usually used on building steam lines.  Now, disc type steam traps do rattle, when their working properly.

    Now, this is just me. When I’m checking to see if a trap is working, I will let the unit come up to working temp/pressure. With the unit idling for about 20 min. CAREFULLY touch the drain line side of the trap line, away from the trap. If its just warm, the trap is probably working. If its cold, the line is probably clogged somewhere. If it takes your skin off, the trap is probably stuck open.

  • olivero - Florida

    April 6, 2018 at 1:31 pm

    Lol, emphasis on carefully?


    I’ll give that a shot when I get a chance, thank you.

  • fixbear - ADK NY

    April 6, 2018 at 5:59 pm

    That’s perty accurate Rico.  Cept for losing your skin if it is a leaker. Wet your fingers first!

  • guest

    April 7, 2018 at 5:20 am

    Anyone can do it the right way. Wetting your fingers takes all the fun out of it.

  • ectofix - Nashville

    April 7, 2018 at 7:44 pm

    You asked about a thermostatic “trap”. 


    Everyone here responded under the notion that you were talking about a trap used on the condensate (outlet) side of some form of heat exchanger employing live steam as a heating medium (vice using heating elements or gas burners).


    In live steam applications, the steam from a central boiler someplace enters the heat exchanger of the equipment and gives up its heat to HEAT something, then it condenses to water.  A typical “trap” lets that condensate (water) either return back to the boiler to be reheated…or goes down a drain – depending on the setup.

    I have allot of steam-heated equipment where I work.  The most common TRAPS we use are either “bucket traps” – made by Armstrong…or “thermostatic traps” made by Sarco:


    THAT trap performs the function that I’d originally described.  Per the Cleveland service manual:


        The water in the boiler is heated to steam.

    • As steam is generated and pressure builds the air is pushed out through the steamtrap.
    • When steam goes through the steam trap and heats it to 192 degrees it closes.


    That’s written on page 8 of this manual: 


    Although I’m not there looking at it, I believe that the brass T-fitting depicted is connected to the pressure gauge and the pressure switch…which controls the heat cycle.  The barb fitting connects to a hose leading to the cooking compartments.


    CLEVELAND calls it a trap…since it does INDEED trap steam in.  I think a more aptly described as an AIR VENT.  But…they don’t pay me to name their parts.

  • olivero - Florida

    April 8, 2018 at 9:47 am


  • olivero - Florida

    April 8, 2018 at 9:54 am

    Thank you for the detailed response Ectofix, very much appreciated. 


    Makes sense though, so pretty much as soon as it senses steam is passing through it (as its getting heated) and the air has gone away, it closes.


    Makes sense.

  • fixbear - ADK NY

    April 8, 2018 at 4:07 pm

    Ecto, it is not primarily a air vent.  However it does vent non condensables.  Being it is placed at the bottom of the main steam line at a low point. It’s primary purpose has to be to drain condensate. Gas venting secondary.  Otherwise it would be placed at the middle or top. Then it would be a air vent.


    Definition of a Thermostatic Trap is: 

    How does a thermostatic steam trap work?
    Mechanical and thermostatic steam traps basically open when condensate and inert gases need to be removed, and close when all the condensate is removed. The process repeats when new steam is condensed again and ready to be drained. Steam traps work best when sized specifically for the application they are used on.
    And yes, they have a temp element that when cooled opens to not only veny air out, but to prevent thin wall heaters from collapsing.
    Run a still once with a thumper over condensing.  Opp’s.  Sucked the copper right in.
  • ectofix - Nashville

    April 8, 2018 at 7:52 pm

    A STILL?  I‘ve only had the very rare experience of indulging in enough sips of that device’s product to keep me away from it…and I live in TN!  That stuff turns me upside-DOWN!


    I acknowledge that you have a significant edge on me for knowledge and experience of steam systems, fixbear.


    My experiences with that little trap that olivero asked about has been when I was called to look at a boiler-based steamer that’s not heating.  Of course, I walk up to it, do a cursory look-over of things, then…


    If that trap is clogged, here’s what happens:

    • Starting from a stone-cold unit, turn the power switch.  The controls calls for fill.  If that little trap clogged, the unit’s pressure gauge will slowly climb during the FILL cycle.
    • Once the upper water probe satisfies, IDEALLY – the boiler pressure should be 0 psi…since the trap should have vented displaced air.  But, it didn’t.
    • So, by the time the boiler is FULL, the compressed air registers enough pressure to have already satisfied the pressure switch.  As such, the pressure switch won’t call for heat.
    • Usually my next step would be to relieve that pressure by simply entering one of the cooking compartment into a cook cycle.  When that compartment’s solenoid valve opens, the compressed air vents into the cooking compartment, the boiler pressure drops to zero, the pressure switch closes…and the heat circuit energizes.


    In such a case, I’ve repeatedly found that the trap or its plumbing was the culprit.  In one instance, the boiler was so scaled up that it had clogged the port leading to that trap and I had to chisel through the scale in the fittings AND replace the trap.


    I HATE scale.  I think I had wore away my fingerprints more than once for having to deal with it.


    For that trap to also serve for expelling condensate?  I’d never looked at it that way before.  Your explanation makes perfect sense.

  • olivero - Florida

    April 8, 2018 at 8:57 pm

    Sometimes I think I got this kitchen stuff down pretty well.


    Then I ask you guys a question and I remember just how little I still know.


    That’s why I keep coming back.

  • fixbear - ADK NY

    April 9, 2018 at 7:41 am

    ectofix wrote:


    I HATE scale.  I think I had wore away my fingerprints more than once for having to deal with it.



    Your not alone on this. And today it is unnecessary with the modern electron level  softeners. That separate the minerals out at the atomic level.. No salt backwash or green-sand. They just coagulate and fall to the bottom of the softener for back-flushing.


    Had a Dishwasher booster that it took 2 prybars to remove the elements from the build up.  And they are never in a easy place.

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