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Pressuretrol mystery

JEFF5255 Member Posts: 9
I've been getting calls from a customer of mine who owns an apartment building heating with a big old steam boiler. (I was not servicing this system prior to now and am not a steam expert by any means) The system has an energy control system which calls for heat pending the outside temp and adjusts the run cycle times based on the outside temp. Each time I arrive the controller is on and calling for heat. Each time I arrive one way or another I end up at the Pressuretrol. (Original one was the small gray Honeywell PA404) The 1st trip out I just tapped on it and the signal (yellow light) lit up and the burner fired up. 2nd time out was the same so I figured it was a bad control and replaced it. System worked fine for about 3 weeks then went off again and would not fire up. Once again all systems checked out and when I got to the Pressuretrol and took of the cover to check it out and the system fired up. Figured we had another bad control (weird but not out of the question) found out those old Style (small gray one) is no longer approved in my state so I got the new Honeywell model with the clear plastic face. Replaced it and away we went! Success! Until about 3-4 weeks and another call for no heat. Again found all things pointing to the Pressuretrol, I talked to my electrician about it and the oissibikity of a loose wire somewhere in the circuit and he told me to simply take the cover off and jump out the 2 terminals if it fires up you got a problem with the control. So I did what he said and it fired up. I just can't believe I have 2 new pressuretrols that are bad. Well after I left last time the system worked again fine through February and now its off again. This trip (saturday) I disconnected the wires and pulled out the pigtail to see if it was clogged and it was plugged solid. I cleaned it thoroughly and the port in the LWCO and put it back together wired it and turned on the power and burner fired right up! Thought to myself "finally found the problem" darn control was malfunctioning because the port was clogged! Went home and got a good night sleep next day got the call again system down again. I'm on my way there as I type this.

Any ideas anyone can think if here as I'm at my wits end.

Also want to mention that I'm not a steam expert I just know the basics from being in the business and reading Dan's books but I'm pretty sure this is an original vapor system and I've read some posts about vaporstats and I'm just wondering if I inherited someone else's problem here and maybe this system needs a different type of Pressuretrol?? I'm not familiar with a vaporstat or how it operates differently than a Pressuretrol? Hope someone can help clarify that too?

Thanks, please feel free to call me which would be faster and much appreciated if you think you can help. Jeff 860-948-8813

Signed, tired and baffled!


  • ChrisJ
    ChrisJ Member Posts: 15,436
    Switch failures

    I'm not a pro, but if I had switches failing I would assume I was either drawing too much current through them or have a highly inductive load connected to them.

    What all is connected through the Pressuretrol?
    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
  • Jamie Hall
    Jamie Hall Member Posts: 22,888
    Did you get anywhere?

    Pressuretrols are usually pretty bullet-proof critters, and the microswitch can usually take a pretty good amount of current -- although like any switch, they can be overloaded.  Usually, though, if a switch fails from overload it will fail closed (contacts welded) rather than open -- and whacking it won't help!

    If you still having the nightmare, can you put a low pressure gauge on an independent pigtail to see what is really happening to the pressure?

    And what are the settings on the pressuretrol?  Is it possible that the cutin pressure is low enough that it isn't being reached reliably?  That can happen...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Fred
    Fred Member Posts: 8,542

    Depending on if they ever blow down that LWCO, it is quite possible the pigtail or port in the LWCO is plugged up again. Vaporstats work basically the same as a Pressuretrol, just more accurate and at lower pressures.