Steam Vent for a 2 pipe

suz2078

We have a two pipe Steam system. One of the radiators only gets hot at the beginning. If I turn the thermostat up to about 75-76, open a small bleeder that I put on this radiator, and bleed it for a little while the radiator will get hot all the way through. But when I take the thermostat back down to about 68 it only gets first three cells hot. Someine suggested I put on an automatic vent take out the manual one. Any suggestions?

Danny Scully

Let’s take a step back. 1st question. Are you cold in the room?

suz2078

Yes it is very cold in this room

Ironman

Unless it's a very old two pipe vent system, there should be no vent on the radiator. These system were installed before radiator traps were invented. If there's a trap on your rad's, there should be no vent on them. You made need the trap rebuilt and (if you have them).

In no case should it be manually vented.

suz2078

Ok so we are new this radiator heating and we are trying to learn everything we can. So having said that... what is a trap? And could our problem be the return line with the cap on it? I know cap is probably not the correct term but it is the only way I can explain it.

Danny Scully

Ok, question 2. Where are the pictures?! please post as many pictures as you can.

suz2078

Here are photos of the radiator and parts in the basement.

suz2078

The odd thing is that all the cells heat when we crank the heat up to 75 or 76. But when the heat is set at 68 only a few cells heat up.

JUGHNE

The device on the lower right of the rad is a radiator trap.
It should be internally open to pass air until steam gets to it.
Then the high temp steam closes it. As the steam condensates to cooler water temp then the valve opens to drain the water away until steam gets to it again.
If you bleed the air out then steam will enter and give you heat.
But if the trap is stuck closed the condensate water will not drain out and eventually you may get water hammer in that rad.

That air should go down into the return pipe and be released into the basement thru another air vent.

Do you have any other rads acting this way?

JUGHNE

The longer the boiler runs it will compress the air in the rad.
That is why it will heat farther across.

Danny Scully

Yes the trap is the lower right of your 2nd picture and your 4th picture. I know pictures can be deceiving, but it looks like the valve isn’t fully open. Have you checked that?

suz2078

-We have 1 other rad that does not get hot all the way until the thermostate is cranked up.
-we just double checked the valve and yes it is all the way open.
- we have heard a loud banging like noise in this room every now and then so I am guessing this is water hammer.
-how can we see if the trap is open or closed? Or if it is working?

suz2078

We have 9 rad’s that are heating all the way and 2 that are not heating all the way at 68. We are just wondering if something is wrong with these 2 since the others are fully heating and these 2 are not at the same temp.

JUGHNE

Does the trap body get hot before that end of the rad does?
Steam will close the trap from either side of it, above or below the floor.
A bad trap can let steam into the return system, that might travel to a good trap and close it. This would stop an otherwise good rad setup to not heat. It also could ruin a good trap.
A rad with the bad/stuck open trap may heat very well, all the way across because the steam shoots thru it into the return piping in the basement. Then it possibly closes good traps preventing those rads from heating.

suz2078

Right now the rad is cold where the trap is and the trap is cold. I am going to crank up the heat so the entire rad heats and then see what happens with the trap.

suz2078

So we cranked the heat to 75. All the traps were hot except the one we are concerned about in the cold room. So we opened the manual steam vent on this rad for 5 min and now the trap is hot like all the others. But it required me opening the manual vent in order for the trap to get hot.

And no the trap does not get hot before the rad.

Jamie Hall

OK. The trap is failed closed. That looks to me like a pretty plain vanilla trap; most of them can be rebuilt. The cap with the hex on it comes off, and the guts can be replaced.

Could you take a picture close up of the top of the trap, and post it? There's a chap on the forum -- @Sailah -- who is Barnes & Jones, and he will be able to tell you exactly what replacement part to use.

Before you put in the replacement, though, make sure that the pressure is kept low enough. Could you also post a picture of the front of the boiler with all of the controls?

Gordo

That looks like a Dumham #1 series radiator trap. Don't know about the other end-of-main trap. That one looks like a "inverted bucket" style trap and should be replaced with a modern 6-bolt style float and thermostatic trap ("F&T").
The vent shown is a Hoffman type, either a #75 or even, heaven help you, a #76. That should be replaced with a bigger and better vent such as the Gorton #2.

suz2078

Thank you all so much for you advice and input!
Here are the photos is the trap and the boiler.

suz2078

So Gordo is the vent you are talking about the thing downstairs with the red glue around it? This is what what you are saying should be replaced with a Gorton #2?

suz2078

You are all so knowledgeable and helpful. We live about 40 minutes outside of Pittsburgh Pa. If anyones knows of someone who works on steam systems in our area please share them with us! My husband is handy so he can replace the items mentioned, but it would be wonderful to have someone knowledgeable and trustworthy in our area

Gordo

The thing with the red caulk around it appears to be the "bucket" trap. That was never the best type of trap to use in heating systems.
https://us.v-cdn.net/5021738/uploads/editor/jb/gx850hniz9qn.jpeg

Gordo

Confirmed "Dunham" thermostatic steam trap on that radiator.
Not sure if is a #1 or a #1A.
https://us.v-cdn.net/5021738/uploads/editor/yv/bibtpze8f5e2.jpeg

Gordo

https://us.v-cdn.net/5021738/uploads/editor/od/dj6fq5pvksyh.jpeg
I believe this is your photo of the Hoffman #75 (or #76).

Ironman

Another more involved project that needs to be addressed is your near boiler piping. Both steam taps should have been used for that sized boiler. As it is now with only one steam riser, the steam velocity is too fast and it's probably drawing up water with it giving you wet steam.



That's a 9 section, 299k btu model that you have. Notice that the chart calls for a MINIMUM of two 2" risers and a 3" header. If it's a rebadged Dunkirk version, it would have 2.5" steam tappings and it should have two 2.5" risers.

JUGHNE

Has anyone else noticed a crossover trap above the bucket trap in the basement?

JUGHNE

Your pressure relief valve is the bronze gadget on the top of the boiler, it has 3/4" copper pipe connected to it. Does it really run up the wall next to the boiler? Where does that pipe end?
It is supposed to go down to within 6" of the floor. It is something you want piped down in case it opens and releases steam.

There are good books here for homeowners, really easy to read and learn from. Look for "We Got Steam Heat!" a great primer.
Then "The Lost Art of Steam Heating" for a little more advanced lnfo. Amazon can get them to you. They have a great ROI.

Steamhead

Ironman said:

If it's a rebadged Dunkirk version, it would have 2.5" steam tappings and it should have two 2.5" risers.

It is, and it should. I'd also make the header 3".

suz2078

-So the pressure relief valve is vented into the chimney (I attached a photo). Is this ok?
-I attached a photo of the cross over trap above the bucket someone mentioned this above. We will replace this but can anyone tell us what to replace it with?

Steamhead

That safety valve piping is NOT OK. It needs to be removed. The proper way is to come out from the safety valve and drop to within 6 inches of the floor.

Jamie Hall

That crossover trap is also a Dunham -- same kind. It needs to be working properly for the system to work properly as a whole.

Phil945

I have a two pipe system with a Hoffman #76 main vent. (Interestingly, it does not appear to have traps on the radiators.) The vent doesn't seem to release the air very quickly, and a couple of radiators on the second floor do not heat very well. I was considering replacing the main vent with a Gorton #2 to see if it would help, but wasn't sure it was the right decision.

Based on the previous comment about the #76, it sounds like I my thinking is correct. Is there any reason I shouldn't replace the main vent with the Gorton #2?

Jamie Hall

Is this the same system to which the rest of this thread is referring? If not, it would be much better in the interests of avoiding confusion to start a new thread.

I wouldn't care to answer your question without knowing more about the system it is part of, as the Hoffman #76 is a specialised vent for vapor vacuum systems, and it may be that that is exactly what is needed.

Phil945

Thank you for your reply Jamie. I have created a new thread entitled "Vent Issue on a Two Pipe System".

I had seen some mention of a vacuum system when looking up a description of the #76 and am not familiar with one at all.