Steam traps

Todd_9

How can you identify a failed trap? What does the inside of a good trap look like as opposed to a failed one? I was also told to "shoot" the trap with an infared gun but if the temperature change isn't across the trap, how will this help?

Steamhead

Depends on the type of trap

On the usual thermostatic radiator trap, I feel the return to see if it is steam-hot. It shouldn't be. You could also use your heat gun to do this.

Float or float-&-thermostatic or bucket traps discharge condensate at steam temperature so the above test won't work. I like to install valves on tees just downstream of these traps that will let me see what's coming out. Alternatively, if the dry return is steam-hot, you can shut off the steam to the equipment drained by different traps to see which one is leaking steam into the return.

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todd s

checking traps

Do you mean like a boiler drain below each trap to see if its air or steam coming through? It seems as if there may be some stuck closed. They get steam across the top of the radiator but not all the way down. If however there was one stuck open, why does this stop the rest from heating? There are vents on the return main so wouldn't the air from that(open)trap just go down and vent in the main? There is no hammer in this system just one area that's not heating.(approx 11radiators all in built in window boxes) please don't tell me I have to pull all the traps in this area.

Steamhead

You might have to

but first, make sure that vent on the dry return is working. Second, check to see if there's any steam in the dry return. This can pressurize the return and shut the vent, killing steam circulation.

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todd s

return vents

I have new larger vents, they all seem to be working. I don't feel any heat in the return main. Should I try pulling the vents and running the system to see what happens?

Bill Marsh

Check your traps

I would just get Tunstall capsules for the 11 radiators that don't work.

If one fails open, the steam can get to the others and kill them too.

I'm just a homeowner. But we have 17 thermostatic traps on radiators and two others in a crawl space between the main and the dry return.

I opened all 19 and swapped out the old traps. Half of the old ones had mfg date of 4/1937 on them so they owed me nothing.

System works a whole lot better with new traps and all the radiators heat. The kids are happy.

It took about 3 hours to do the whole job.

Walt Deacon

Failed Traps

I have found an ultrasonic stethescope is more reliable than temperature. But... I work on 15 to 150 psi systems mostly. Anyway, a failed closed trap will be cold, and a failed open trap will "light up" the stethescope. The only problem is: the stethescope costs between 500 to 1000 bucks, and takes some experience to set up and use correctly.
I also like Marsh's suggestion, since by starting out with all replacements, you're dealing with a known quantity.
In addition to Tunstall, you can get good replacement elements from Barnes & Jones, or Hoffmann. They are all reputable.
Have fun!