ATTN: 2 pipe steam heating experts !! Need help!

gasdoc75

Hi there. I am new to this forum and need some advice.

I live in Long Island. Bought 82 year old house 2 years ago. 2 pipe steam heating. 2 zones. All radiators steam except for 2-hot water ones (on the other zone). 30 year old Weil McLean steam boiler maintained well. Performing at 90% efficiency.

All radiators heat fine except for a 200 pound cast iron radiator in my master bedroom. Since I moved in, it has not been heating well. Only getting about 1/4 hot. I had to change the supply valve because there was no handle on it. The supply line piping gets hot as hell. The return line is ice cold. For some reason the person who helped me change this put an air vent on this radiator (which I learned was a mistake and removed it). There is a shim on the supply side about 1/4 inch towards the return.

After getting through last winter with a space heater in this room, I contacted a company that deals with steam heating and is the supposed experts in steam heating . Their best person assessed my situation and found that the steam trap was empty on this radiator. While recommending to change 12 other steam traps (that were all working fine ), I refused and told him just to change the one on this non functioning radiator. I later learned that all he had to do was change the inner capsule instead of charging me an arm and a leg . NO change in the heating of this radiator. Fed up, the plumber came out again and went to my basement and suggested to compress the whole system and that there might be a blockage in the radiator. After seeing the expensive quote I refused.

After doing more research, reading and speaking to a few more people, I found out that i have a Hoffman differential loop. I've read a few things about this, but it is over my head. Is this part still functional in my heating system??? I was told I have a vacuum system, There is a master vent on the differential loop but I don't feel any air coming out of it . Don't i have to have a functional vent for the system to work, otherwise none of the radiators would heat? The vent says Hoffman number 15. Someone advised me to change the master vent and also check the crossover steam traps in the basement??

I contacted the prior homeowner and asked if they did any work near this radiator which they said no. They said this bedroom was always the coldest room in the house and was told that it was the last to receive the steam on the heating cycle. (Not true , this Room is actually closest to the boiler).

I am basically stuck on what to do next. Any advice is appreciated. I don't mind paying the right person for the proper diagnosis and repair... can anyone recommend someone with expertise in New York with 2 pipe steam heating? I have attached some pictures.

Thank you.
Eric

Addendum: I cranked the thermostat the other night, took the air vent off and could hear a hissing sound and pressure out of the hole. 3 hours later and no steam ever came out

Paul S_3

How far in long island are you? A good steam man is not inexpensive

New England SteamWorks

"There is a master vent on the differential loop but I don't feel any air coming out of it . Don't i have to have a functional vent for the system to work, otherwise none of the radiators would heat? The vent says Hoffman number 15. Someone advised me to change the master vent and also check the crossover steam traps in the basement?? I cranked the thermostat the other night, took the air vent off and could hear a hissing sound and pressure out of the hole. 3 hours later and no steam ever came out "

1. Yes, the master vent on the loop needs to be able to vent air. The original one, if still working, is likely undersized.
2. The crossover traps should be checked as well.
3. If you mean the main vent was removed, you shouldn't have steam there so that's good. At least you know the crossovers aren't failed open.

Try removing the plug on the radiator where the guy put the vent (which was incorrect) just as an experiment. See what happens.

Is the pictured radiator a one-of-a-kind in your home, or are there others that match it?

A little more info here

Jamie Hall

Assuming the Hoffman Differential Loop is still connected the first thing to do is to check the cutout pressure. It must, repear, MUST be less than 12 ounces per square inch. If you have a pressurestat, it won't be. You have to have a vapourstat.

Second, as @RI_SteamWorks said, the master vent at the loop is critical -- and is likely undersized. Further, there should be no other vents anywhere on the system. None.

Third, if that radiator's feed is getting nice and hot as you mentioned, but the radiator isn't, then there are really only two possibilities: the trap is failed closed or the valve is failed closed. Um... come to think of it, there is a third possibility which is unlikely: where does the return from that radiator go? It should go into a dry return and back to the boiler. Did some clever soul pipe it to a wet return instead? Or through a water seal? Check that out.

Sailah

If you want to test trap function VS blockage, close the radiator valve. Loosen cap wearing gloves. Slowly open radiator valve. If steam starts leaking out of cover, you've either got a trap problem or blockage downstream.

Usually radiator traps are designed to fail open which would still allow steam to pass through the radiator which would mean you would get some heat out of it.

gasdoc75

Thank you for all your advice. I am still trying to digest it all , as I am a novice in the steam heating world. To update/summarize:
I did replace the steam trap. Even though it is brand new, could there be the possibility that it is still failed closed?

I understand that the master vent at the differential loop is critical. It is the original (Hoffman number 15) and I assume it is non functioning ? there are no other steam vents anywhere on the system.

Homeserve came to my house and said that my Weil McLean boiler is running at full capacity (200000 BTU) .

A plumber I spoke with recently said that I might need to fix the return line and something about if the return line is below the water line and to check the union.

I have more Pictures. It looks like I have a pressurestat not vaporstat. My steam radiators are of 3 types: cast iron recessed, cast iron standing sand then the radiators with the metal squares at the bottom like an accordion.


Thanks for all your help. If anyone can recommend someone good in queens/Long Island I would appreciate it.

Eric

Jamie Hall

The new steam trap is probably OK; as has been said, they rarely fail closed. For that matter, they rarely fail. The first place I'd look for a problem with that radiator at this point would be the valve, although there is that odd possibility I mentioned.

The master vent is critical -- but if the system heats at all, except for that one radiator, it is probably working. However, a bigger one (or two or three!) probably wouldn't hurt.

That is a pressuretrol, It is set too high, but it can't be set low enough anyway. It can be kept as a backup - never a bad idea -- but you need a vapourstat to control that system properly.

There are a number of contractors who are competent who service your area. Try the "Find a Contractor" tab from this site; look for New York (state). You may find that they are a wee bit busy at this time of year...

Sailah

I doubt the trap is failed if new and most traps fail open. I suspect you have larger issues.

Fortunate for you, you have the largest concentration of experts in your area. Expect the good ones to be busy. And for it to be worth it.

http://heatinghelp.com/find-a-contractor/

Fred

@Jamie Hall and @Sailah , given the trap on that radiator was empty before he put a new capsule in it, is it possible that something from the old one could have broken off and dropped into the return pipe blocking it? If not, Is is possible that that return pipe is just clogged? Can he take the cap off of the trap, remove the capsule and run a snake down that pipe to make sure it is open?

Fred

Another thought, if the radiator in question is the large recessed one, and according to the OP, it gets about 1/4 hot, and, from the looks of the wall area around that radiator, is it possible that someone changed out the original radiator for one that is way to large for the size of that supply pipe to provide sufficient steam to do much more than what it is?

Steamhead

Don't have the info here, but ISTR the Hoffman #15 vent was designed differently from the ones we're used to. The thermostatic element on this vent is positioned underneath the body of the vent, and the vacuum check was designed to stay closed until a couple ounces of pressure opened it.

Remember, the Differential Loop regulates the ΔP between the steam and return sides of this system by admitting some steam pressure into the dry return, and the vent needs to close quickly when this happens so the Loop can accomplish its purpose. This allows condensate to return tho the boiler. See chapter 15 of Lost Art for details.

As much as we all love @Sailah , this is not the place for a Big Mouth vent since it does not have an internal float. Any vent placed on the dry return of a Vapor system needs to be able to close if water rises that high, and the Big Mouth won't do that. The Gorton #2 rules in this application.

New England SteamWorks

Is the pictured radiator a one-of-a-kind in your home, or are there others that match it?

gasdoc75

Hi RI_steamworks. I have a combination of radiators . the big cast iron ones with the individual fins/sections, the one in the picture (vertical cast iron) , and then ones with metals fins at the bottom

Fred

@gasdoc75 , After re-scrutinizing your pictures again, I am almost certain that long recessed radiator in your first group of pictures is the problem radiator in your master bedroom (please confirm that) . What I see and what I now believe your problem to be seems pretty straight forward. Look at the piping under that radiator, both the supply and the return lines. It is very clear that, at some point, someone changed out a much smaller radiator for that long one. In doing so, they added about 6 to 12 inches to the supply side by turning the supply valve 180 degrees from what is typical and then adding a nipple. On the return side, they added a long nipple, maybe 24 to 30 inches to carry the return back to where it originally came up out of the floor. Typically the original radiator would have fit between the supply pipe and the return pipe. Having done what they did, you have one of two issues that need to be addressed, maybe both.
1. This radiator may be way to big for that 1 inch supply pipe to provide enough steam to heat that radiator all the way across. We need the dimensions of that radiator (I believe it's a Sunrad), height (I think 20 inches) , number of sections and depth (should be either 5 inches or 7 inches). Once we have that info, we can calculate the EDR of that radiator and determine if the current supply pipe can support it.
2. By piping it the way they did, while you have the radiator pitched towards the return end of the radiator, the actual return pipe is about 2/3's of the way back, towards the center of the radiator. That end of the radiator and that return pipe extension are both probably holding water so that air and condensate can't get past that return extension and drop down the vertical return.
One of two things need to happen. Once we determine the size of that radiator relative to what that supply pipe can support, you may need to either increase the size of the vertical steam supply pipe, from the main all the way up or find a smaller radiator that can be supported by that supply pipe and actually fit in between the supply and return pipes as well.
OR, if the supply pipe can actually support that rad, you will have to figure out a way to slope that horizontal return extension enough to allow the condensate to drain. That may entail raising the entire radiator some and then maybe using a couple 45's to get the needed slope without affectng the height of the supply valve and any horizontal piping under the floor.
Sorry for this long post but I did want you to understand what I believe the issues to be.

New England SteamWorks

Fred has emphasized what I was trying to get to. Both the type of radiator and the way it is piped seem odd to me. Which is why I ask yet again if you have another radiator of the same type in your home, piped as this one. If you do not, I think we have our problem.

What dissuades me from this thesis is how well that radiator is recessed in the wall and matches the window size.

So. Do you have another such radiator, or is this one a one-off?

Inquiring minds would like to know...

Fred

@gasdoc75 and @RI_SteamWorks , It also has a vent on it, at the left side which should not be there either.

gasdoc75

RI_steamworks and Fred. Thanks for your responses. So, this cast iron radiator style is not a one off. I have another one in a another room that is functioning quite well. Heats pretty quickly and the room is nice and warm. I have attached a picture and can unscrew the cover if needed. It had 17 sections and about 47!inches long. The room is about 210sq feet I think . Looking thru the cover , the steam trap is ADJACENT to the return side, with minimal piping connecting it.

The problem radiator : Length=67 inches . Depth 5 inches. Height 20 inches. 29 sections .
About 230 sq foot with 12 foot Ceilings. one person in the past did comment that this is too much radiator for the room size . If you look at the picture, there was some type of wood repair done at some time . The diameter of the supply side I think is 1 1/4 inch and definitely smaller on the return (think and inch). You can see a little shim on the supply side that has always been there.

Should the supply and return piping be the same diameters? Should the supply valve distance and the steam trap distance from their insertion points be roughly the same distance ? It is about 16 inches from the return side of the radiator to the vertical return piping . Also, basically all the vertical piping and elbow siZes are also smaller than the return side.

Hope this can shed some more info....

New England SteamWorks

" I have attached a picture and can unscrew the cover if needed."

I think it would be helpful to unscrew the cover so we can see the other radiator and how it's piped, and verify that it is indeed the same type.

JohnNY

"While recommending to change 12 other steam traps (that were all working fine )..."

How do you know they were working fine? Keep in mind that just because the connected radiator receives steam doesn't necessarily mean the trap is doing all that it's supposed to do.

I have no idea what company you called in to look at this, but new traps throughout the home are rarely ever a bad idea (we're only talking about 12 of them), especially seeing the condition of your system which looks like it hasn't had a lot of interaction with qualified contractors recently.
I'm not suggesting this is you (I'm speaking to the pros here), but oftentimes, the biggest obstacle to a pro in truly reaching a client's desired goal is the client's failure to see the value, or some times necessity, in comprehensive restoration of the system.

nicholas bonham-carter

It looks like the information for the Hoffman system is here:

https://heatinghelp.com/assets/documents/hoffman-data-book-1925.pdf

I think Fred is on to something with his analysis of the piping under the radiator. Water which will not drain out completely from those pipes will put an additional resistance to the air removal of the radiator, at the beginning of the heat cycle. This will cause that radiator to heat up more slowly than the others.
Take out the plug from the radiator vent tapping, while the system is off, then fire the boiler, with an assistant to cut off the boiler when the experiment has been completed. Dry steam should come out of that vent as quickly as the other radiators begin to heat up. If not, there may be a pool of water in the supply piping impeding it.
With the plug back in, then remove the cover of the trap, and fire again. If steam comes out of the trap quickly, then most likely, the problem is in the return piping.
Be careful with steam, as it is such an excellent means of heat transmission, that the burns can be severe.--NBC

Fred

@gasdoc75 , The radiator has an EDR of 65.25. If the supply pipe is 1.25, it can handle that but I'm still suspecting it is a 1 inch supply. I also see "1" on the side of that supply valve which suggests it is a 1 inch valve. Double check the diameter of that pipe. inch is not likely to support that radiator but you do get more EDR out of that pipe, being a teo pipe system and that supply does not also have to handle return condensate.
At the moment I think the biggest issue is the return piping. I see that there is a 3 or 4 inch nipple under that trap. If you can take that piping off, from the radiator to the trap, reduce the length of that nipple under the trap by maybe a couple inches and then use 45's at the radiator and at the trap end of that long return pipe so that you have really good pitch in that pipe, I think you will solve that return problem. To answer your question, no, the return pipe does not need to be the same size as the supply pipe. The way your supply is set up is fine, the only question is if that pipe is 1 inch or 1.25 inches. If 1 inch, I don't think you will support that radiator but it may heat it 2/3's of the way across which may be enough for that room. You can make that decision and we can discuss the best way to cross that bridge when we get there.
BTW, I am sure when you take the cover off of that smaller radiator you will find the plumbing set up to be different with the return piping most likely on the outside of the end of the radiator or, if on the inside, connected right to the trap with a very short nipple.

gasdoc75

Ok. I took off the radiator in the other bedroom which is of similar size. This room heats quickly and has the similar type of cast iron radiator but almost half the size. I am attaching pictures .

In terms of the piling on the supply and return ends:

Master radiator (problem radiator) piping -: supply
Vertical O.D 1 1/4.
Horizontal- OD 1 1/4

Return - OD 3/4 horizontal
Vertical - 3/4

Large bedroom (radiator half the side heats well):

Supply
OD horizontal 1 1/4 OD

Vertical 1 1/4
Return
Horizontal 3/4
Vertical 3/4

Could we be onto something ? The large cast iron radiator that is only heating 1/4 if the way has the horizontal piping rhat extends out from the ends. This doesnr happen on the other radiator.
Please chime in!!!

Thanks
Eric

gasdoc75

Here are the pictures

gasdoc75

Please check out the pictures

Fred

@gasdoc75 , Those pipes, are 1" supplies. The 1-1/4" measurement you are getting is an outside dimension. (1-1/4"OD is 1" inside demension). For that smaller radiator, 1" can heat that radiator all the way across. On the Master Bedroom Radiator, a 1" pipe is not adequate to support 65 EDR. You may get about 2/3's of that large radiator heated with a 1" pipe on a two pipe system. That and the extended horizontal run on the return are the issues keeping that radiator from heating. As I suggested earlier, in this thread, shorten that nipple under the trap by a couple inches and use a couple 45's (one at the radiator end and one at the trap end of that horizontal) and you will get about 2/3's of that radiator hot. See if that is sufficient to heat your bedroom. If, not, you will have to have a 1.25" supply pipe run to replace that 1" pipe to support that 65 EDR radiator.

Koan

Pic 5819 earlier on the left hand side looks like it has a bleed valve. I thought they were just for hot water heat.

Fred

Koan said:

Pic 5819 earlier on the left hand side looks like it has a bleed valve. I thought they were just for hot water heat.

They are for Hot water systems. The OP said earlier, somewhere in this string that one of the service people that came to look at the system installed that bleed valve, in error. Clearly wasn't a steam guy.

Paul_11

Gasdoc75,
Did you ever solve your steam issue?