Is this a steam trap?

Jamiedle · 4:58PM

I have a house built in 1930 with two-pipe steam. A contractor said he didn't think this radiator (and a couple of other similar ones) had a steam trap. But I'm wondering if this elbow-shaped piece is actually a steam trap. Thanks in advance!

mattmia2 · 5:04PM

it is a vapor system, it doesn't have traps. that is i think a water seal, maybe it is a broomell system.

don't let them touch it unless they understand what a vapor system is.

the boiler through correct sizing and a vaprostat keeps the pressure low, under about 8 oz/in^2 and that vapor valve on the radiator meters the amount of steam that is let in to the radiator to less than what the radiator can condense so it is all condensed to water before it gets to the outlet of the radiator.

keeping the pressure very low, a few piping things and possibly some specialties at the boiler are critical to making that system function properly.

pecmsg · 5:49PM

where is this house located.
you do not want them working on that system.

Steamhead · 5:57PM

It's an O-E Vapor system. That return fitting is a water seal with a small hole in it to let air escape from the radiator. You can find it chapter 15 of @DanHolohan 's excellent book "The Lost Art of Steam Heating"- the latest version is here:

https://www.heatinghelp.com/store/detail/the-lost-art-of-steam-heating-revisited

Jamiedle · 5:57PM

Wow! We've never known this was a vapor system, even after having two contractors who are supposed to be steam system experts. We are in Ferndale, Michigan, just north of Detroit. I found this in Holohan's book and it looks just like what we have on many radiators, although it doesn't seem consistent around the house. And apparently if we have a vapor system, we shouldn't have a pressuretrol (which we do) and should have a different, more sensitive control for the lower pressure?

Steamhead · 6:01PM

@Jamiedle , the book I linked to above goes into a lot more detail. How about some more radiator pics, including ones with different fittings, and some pics of the boiler and any devices in the piping near it?

mattmia2 · 6:13PM

try @offdutytech. I'm not sure he knows vapor systems but he at least knows enough to know when he needs to ask questions.

i live in ann arbor but grew up in clawson.

Jamiedle · 6:14PM

Thanks, @Steamhead! We do have both books. We got the layman's version because the big book was a little intimidating. But we're looking at Chapter 15 now. Here are some more photos. You'll notice that there's also a hot water pump coming off the boiler which is a whole other topic of conversation. We've had the house just over a year and are making lots of discoveries! Thanks to everyone who is chiming in to help - much appreciated.

First, here's another radiator with a different-looking trap. FWIW, this one has never gotten hot since we've been here. Followed by photos of the boiler.

mattmia2 · 6:28PM

that is a big boiler, i bet it is very much oversized. the circulator i think is for a hot water loop somewhere, that is pretty common and fine if done correctly.

2.5psig is way too much for a vapor system.

does the radiator that won't heat that has the trap still have the vapor valve?

with the insanely high pressure it is very likely you have steam in the returns and that steam is closing the trap from the return side before the radiator can vent and heat. also possible the steam in the return itself is keeping the radiator form being able to vent.

feel the returns, they should not be steam hot. they may be hot but they shouldn't be as hot as the returns.

pecmsg · 6:34PM

the control on the left what does it control? Where do the wires go?

Jamie Hall · 6:42PM

Yes, you do need a vaporstat for that system. The 0 to 16OUNCE per square inch variety, and set it to cutout at 7 ounces with a 4 ounce differential. That radiator that doesn't heat — it may be just fine, but that high pressure is blowing through the other radiators into the returns and will shut it off. The trap on it is a perfectly normal radiator trap. If it's not working, it can be repaired quite easily — but there's no point in seeing whether it's working or not until you get the pressure under control.

The control on the left is an aquastat —but where the wires go or what it's doing is quite impossible to say from the picture.

mattmia2 · 6:44PM

https://forum.heatinghelp.com/discussion/comment/1898146#Comment_1898146

the aquastat is for the hot water loop, it is to fire the boiler up to say 180f when there is a hot water call but not a steam call so the boiler doesn't start steaming on a hot water call only.

pecmsg · 6:56PM

I hope so.
that’s why I asked

mattmia2 · 7:55PM

https://forum.heatinghelp.com/discussion/comment/1898149#Comment_1898149

one problem at a time :)

Is this a steam trap?

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