Two pipe steam radiator problems!

wilder0m

Hi! New to this forum. Just moved into a 3 floor house with several—I believe— two-pipe radiators. Most of them seem to be working, but two of them are not, and are a bit different than the others. 

First, these two rads don’t have supply valve knobs, instead there is an apparatus shown in the photo. What is this? 

Second, one of them has an air valve (shown in next picture), which I read is only typical for a one-pipe system. This radiator is getting hot only on the side without the air valve. Any advice?

Finally, the other radiator isn’t getting hot at all. This one doesn’t have an air valve,
or a supply valve knob (instead a thing that looks like the top picture above). If this one is shut off completely, how would I open it?

Thanks. Looking forward to learning more about how these things work. 

ethicalpaul

Yes that vent is a sign of some problem that someone tried to fix.

wilder0m

ethicalpaul said:

Yes that vent is a sign of some problem that someone tried to fix.

Thanks. Any idea why these two radiators aren’t getting hot (one partially so and the other not at all)? They’re also the only two without hand knobs for the supply pipe. 

Steamhead

@wilder0m , what you have is probably some sort of Vapor system that has been knuckleheaded. Can you post pics of some of the other radiators in the system?

ethicalpaul

wilder0m said:

ethicalpaul said:

Yes that vent is a sign of some problem that someone tried to fix.

Thanks. Any idea why these two radiators aren’t getting hot (one partially so and the other not at all)? They’re also the only two without hand knobs for the supply pipe. 

I have some ideas, but let @Steamhead or one of the other 2-pipe experts help guide you, they know better than I do. Good luck!

wilder0m

@Steamhead of course, thanks for taking a look! Here are two that are working fine:



And here is one that is NOT getting hot at all, not even on one side:


The working ones all have hand knobs on the valves. The not working ones don't. No idea if this is a coincidence or a pattern.

Jamie Hall

Interesting. The one that has a weird gadget at the top of the supply does have a valve, and that's the valve -- but somewhere, sometime, the handle has vanished. You may be able to determine if the valve is closed if you can get a wrench on the stem somehow (try not to scare the stem) and turn it. Start off with just trying to turn it a little bit either way. One of the ones which is working is even more interesting in that it has what appears to be a return elbow, rather than a trap -- which leaks me to wonder whether that innocent looking return elbow is one of a variety of patented gadgets found on some vapour systems. Which further leads me to wonder if the whole system wasn't once a vapour system which has been played with over the years.

Is there a return pipe on the radiator with the vent?

wilder0m

@Jamie Hall Thanks for your thoughts. What would be the "stem" to turn (e.g. which piece in my very first picture in original post)?

Yes, there is a return pipe on the one with the vent. It's the same radiator in the first two pictures in original post. First picture shows the two pipes, both on the left side of the radiator. Second picture shows the air valve.

What is a "vapour system"? Is that a synonym for "steam system" or something else?

mattmia2

It looks like it is a vapor system that has been subjected to a lot of knuckleheading. It looks like those radiators all came from another system. One has a 1 pipe air vent, another has a hot water type coin key vent.

If the radiator doesn't have a vapor valve(that special valve that is missing its lever type handle) then it needs to have a steam trap or an orifice plate. Without a trap and without a valve that limits how much steam comes in to the radiator, steam will pass through the radiator and in to the returns and keep other radiators from heating.

Jamie Hall

A vaourr system is a type of steam system, always two pipe, intended to run on very low (ounces) of pressure. They usually have special valves or orifices or traps to allow just enough steam into the radiators but not too much -- at the low pressures. They don't have vents on the radiators, though in some cases they will do no harm, but they do have dry returns (at more or less the same elevation as the steam mains) in the basement, and they do need venting on those.

One rather common reason for problems is problems with the dry returns -- either not vented, or repiped in such a way as to trap water. Might want to look around in the basement to see what might have been done.

As to where to grab on that valve to turn it, a little hard to say without actually looking at it. The stem will be the narrowest part of the shaft sticking up, however. If you get really lucky, there may be flats on it -- and those you can grab with a crescent wrench without damage.

wilder0m

@Jamie Hall Would something wrong with the dry returns or anything else in the basement cause problems with just two out of 10+ radiators?

Between your answer and @mattmia2 's, now I'm thinking we bought a home with a totally jerry-rigged system that barely works. The bedroom is freezing as it's one of the radiators that doesn't work.

Here is a zoomed out view of the problem radiator, and a few of the boiler, just in case these spark any more ideas.

Jamie Hall

Don't despair. And don't give up.

And yes, something wrong in the basement could cause a problem with just two radiators. Or it could be two things wrong.

The presence of the vent on that one radiator suggests that someone didn't understand how two pipe systems work, and put a vent on to try to get some steam to that radiator. Sometimes that works. Sometimes not so much.

First question: Have you got the little book we sell here (shameless plug) called "We Got Steam Heat"? It's a very good introduction to steam heat as a system, though it doesn't go into details, and it is written for the homeowner, not the contractor. I think Amazon has it, too.

What you need to do is to go to the basement and wander around as the boiler is starting to heat up, and see if you figure out which pipes are carrying steam (they'll get hot1) and which might be returns, and then see how far the steam gets in the ones which are carrying steam. Then take a look around and see to the extent you can how each radiator gets its steam. Think of it this way: for steam to get to a radiator, the air has to get out of the pipe going to the radiator, and then get out of the radiator. In addition, a small amount of water -- condensate -- will always form, and that has to get back to the boiler somehow.

See what you can figure out.

Steamhead

@wilder0m , in this system, the air from the rads goes into the dry (overhead) return lines along with the water. The water goes back to the boiler, and the air is vented from the dry return. See if you can find a vent on the dry return, and post a pic of it.

mattmia2

I bet you're going to find some of the returns are hot too.

KarlW

Whereabouts are you located? That can also matter a big deal in getting a reliable mechanic.

Upstate NY seems to have skilled steam mechanics. In my case they kept trying to fix it like a hot-water system.

wilder0m

Jamie Hall said:

First question: Have you got the little book we sell here (shameless plug) called "We Got Steam Heat"? It's a very good introduction to steam heat as a system, though it doesn't go into details, and it is written for the homeowner, not the contractor. I think Amazon has it, too.

What you need to do is to go to the basement and wander around as the boiler is starting to heat up, and see if you figure out which pipes are carrying steam (they'll get hot1) and which might be returns, and then see how far the steam gets in the ones which are carrying steam. Then take a look around and see to the extent you can how each radiator gets its steam. Think of it this way: for steam to get to a radiator, the air has to get out of the pipe going to the radiator, and then get out of the radiator. In addition, a small amount of water -- condensate -- will always form, and that has to get back to the boiler somehow.

See what you can figure out.

Thanks. An update: I had a pro come take a look. We basically did what you described above. All the supply pipes in the basement got hot as far as we could see/touch them before going up into the house. That was about 7 branches off the main pipe.

Then, on one of the problem rads, the supply pipe was hot right up to the valve, but after the valve it was cold or barely warm. On the other problem radiator, the supply right before the valve was cold, but then he removed the valve and immediately the supply pipe got hot and steam was flowing out of it.

So, his preliminary hypothesis was that the supply valves on both problem rads need to be replaced.

BTW, there is indeed a vent on the return, and it is the same elevation as the supply main. Is that what is meant by a "dry return"? After the vent, the return then goes down below the boiler water level.

mattmia2 said:

I bet you're going to find some of the returns are hot too.

If so, what would that be a sign of?

KarlW said:

Whereabouts are you located? That can also matter a big deal in getting a reliable mechanic.

Upstate NY seems to have skilled steam mechanics. In my case they kept trying to fix it like a hot-water system.

Southeastern PA.

mattmia2

I would recommend carefully repairing that vapor valve since it is a special metering valve.

wilder0m said:

mattmia2 said:

I bet you're going to find some of the returns are hot too.

If so, what would that be a sign of?

Steam going through the radiators with an ordinary valve instead of a vapor valve and no trap and in to the returns. That will keep other radiators from being able to vent through the return.

The boiler also needs to be controlled with a vaporstat so it doesn't build more than about 8 oz/in^2 of pressure.

It looks like you probably have a vaporstat but I can't see how it is set.

KC_Jones

wilder0m said:

Jamie Hall said:

First question: Have you got the little book we sell here (shameless plug) called "We Got Steam Heat"? It's a very good introduction to steam heat as a system, though it doesn't go into details, and it is written for the homeowner, not the contractor. I think Amazon has it, too.

What you need to do is to go to the basement and wander around as the boiler is starting to heat up, and see if you figure out which pipes are carrying steam (they'll get hot1) and which might be returns, and then see how far the steam gets in the ones which are carrying steam. Then take a look around and see to the extent you can how each radiator gets its steam. Think of it this way: for steam to get to a radiator, the air has to get out of the pipe going to the radiator, and then get out of the radiator. In addition, a small amount of water -- condensate -- will always form, and that has to get back to the boiler somehow.

See what you can figure out.

Thanks. An update: I had a pro come take a look. We basically did what you described above. All the supply pipes in the basement got hot as far as we could see/touch them before going up into the house. That was about 7 branches off the main pipe.

Then, on one of the problem rads, the supply pipe was hot right up to the valve, but after the valve it was cold or barely warm. On the other problem radiator, the supply right before the valve was cold, but then he removed the valve and immediately the supply pipe got hot and steam was flowing out of it.

So, his preliminary hypothesis was that the supply valves on both problem rads need to be replaced.

BTW, there is indeed a vent on the return, and it is the same elevation as the supply main. Is that what is meant by a "dry return"? After the vent, the return then goes down below the boiler water level.

mattmia2 said:

I bet you're going to find some of the returns are hot too.

If so, what would that be a sign of?

KarlW said:

Whereabouts are you located? That can also matter a big deal in getting a reliable mechanic.

Upstate NY seems to have skilled steam mechanics. In my case they kept trying to fix it like a hot-water system.

Southeastern PA.

Did they remove the valve from the pipe, or disconnect the valve from the radiator? The valve needs disconnected from the radiator to get it off the pipe, but which thing caused the steam to flow can influence what is going on here.

wilder0m

mattmia2 said:

I would recommend carefully repairing that vapor valve since it is a special metering valve.

wilder0m said:

mattmia2 said:

I bet you're going to find some of the returns are hot too.

If so, what would that be a sign of?

Steam going through the radiators with an ordinary valve instead of a vapor valve and no trap and in to the returns. That will keep other radiators from being able to vent through the return.

The boiler also needs to be controlled with a vaporstat so it doesn't build more than about 8 oz/in^2 of pressure.

It looks like you probably have a vaporstat but I can't see how it is set.

My suspicion/worry is that the pro that visited didn't have this level of understanding. He didn't seem concerned that most of the radiators had no trap, and said the valves that he would use for replacements are just ordinary radiator supply valves.

With that said, I think all of the radiators in the house that ARE heating up just have ordinary valves (rather than the special gadgets on the two that aren't heating). So could he be right?

I seem to have a pressuretrol, not a vaporstat:


Not sure how to properly read that, though.

KC_Jones said:

Did they remove the valve from the pipe, or disconnect the valve from the radiator? The valve needs disconnected from the radiator to get it off the pipe, but which thing caused the steam to flow can influence what is going on here.

He removed the valve from both the pipe and the radiator. I'm not sure which one caused the steam to flow.

Jamie Hall

Oh brother. Well, to work backwards. That is a pressurestat, not a vaporstat, and it is set WAY too high. Using the screws on the top, crank the right hand ("Main") slider down to 1.5 and the left hand ("diff") slider down to 0.5.

On the valves. You can use regular radiator valves on a vapour system, but it isn't recommended. The existing valves may be repairable (in fact, they almost always are). If you want to use regular valves, though, be prepared for some work: you will have to remove the spud from the radiator to match up with the new valve. That's no fun. Then you will need to start with the new valve almost closed, and experiment with opening it a little at a time until the radiator, after a nice long run, gets hot about three quarters of the way across, but the return pipe does not get hot. This will take patience. Then mark the valve so when someone with busy fingers messes with the setting you can restore it. You could also use an orifice -- but that takes a steam guy to size and fit, and you don't seem to have one.

In a sense your guy is right -- by accident. If the radiators have working traps, you can use regular steam radiator valves.

wilder0m

Jamie Hall said:

Oh brother. Well, to work backwards. That is a pressurestat, not a vaporstat, and it is set WAY too high. Using the screws on the top, crank the right hand ("Main") slider down to 1.5 and the left hand ("diff") slider down to 0.5. On the valves. You can use regular radiator valves on a vapour system, but it isn't recommended. The existing valves may be repairable (in fact, they almost always are). If you want to use regular valves, though, be prepared for some work: you will have to remove the spud from the radiator to match up with the new valve. That's no fun. Then you will need to start with the new valve almost closed, and experiment with opening it a little at a time until the radiator, after a nice long run, gets hot about three quarters of the way across, but the return pipe does not get hot. This will take patience. Then mark the valve so when someone with busy fingers messes with the setting you can restore it. You could also use an orifice -- but that takes a steam guy to size and fit, and you don't seem to have one. In a sense your guy is right -- by accident. If the radiators have working traps, you can use regular steam radiator valves.

What are the consequences of having the pressure set too high (as it is currently)? I’m wary of changing anything in case it’s somehow in a delicate balance right now based on previous owners’ trial and error. 

As for your last sentence, the majority of the radiators in the don’t have steam traps. And as far as I can tell, they don’t have special vapor valves either. Thoughts on why they (most of them) appear to be working?

Not challenging your expertise here (you clearly have it and I don’t), just trying to understand my situation better. 

Thanks. 

Steamhead

wilder0m said:

Southeastern PA.

Where in SE PA? And can we get a pic of the vent on the dry returns?

wilder0m

Steamhead said:

Southeastern PA.

Where in SE PA? And can we get a pic of the vent on the dry returns?

NW Philly. Here’s a pic of the dry return vent.  

Steamhead

First thing to do is replace that Hoffman #75 with a Gorton #2. This will allow the system to vent faster. Then see how it does.

Jamie Hall

The problem with the high pressure is really two fold. First, it costs you money. At that pressure, probably a fair amount of it. Once the actual pressure in your system reaches half a pound or so, any fuel burned to increase the pressure is a waste. Second, it costs you money: even if any traps or vents survive the pressure, they fail much more rapidly than they would on more moderate pressures.

Do take @Steamhead 's suggestion and swap out that Hoffman main vent for a Gorton #2. Not that the Hoffman isn't a good vent -- it is -- but the Gorton will let the air out of the system faster.

Now on your last query. Steam heat is a little strange in one critical way: often things which look they shouldn't work do, at least after a fashion. It may be that the return elbows aren't quite as innocent as they look -- they may have orifices in them. Or it may be that the valves on the radiators aren't really fully open. In any event, it is quite possible that it works -- as I say, after a fashion. It would probably work more evenly and quite possibly quicker if it were working properly.

guzzinerd

wilder0m said:

Jamie Hall said:

Oh brother. Well, to work backwards. That is a pressurestat, not a vaporstat, and it is set WAY too high. Using the screws on the top, crank the right hand ("Main") slider down to 1.5 and the left hand ("diff") slider down to 0.5. On the valves. You can use regular radiator valves on a vapour system, but it isn't recommended. The existing valves may be repairable (in fact, they almost always are). If you want to use regular valves, though, be prepared for some work: you will have to remove the spud from the radiator to match up with the new valve. That's no fun. Then you will need to start with the new valve almost closed, and experiment with opening it a little at a time until the radiator, after a nice long run, gets hot about three quarters of the way across, but the return pipe does not get hot. This will take patience. Then mark the valve so when someone with busy fingers messes with the setting you can restore it. You could also use an orifice -- but that takes a steam guy to size and fit, and you don't seem to have one. In a sense your guy is right -- by accident. If the radiators have working traps, you can use regular steam radiator valves.

What are the consequences of having the pressure set too high (as it is currently)? I’m wary of changing anything in case it’s somehow in a delicate balance right now based on previous owners’ trial and error. 

As for your last sentence, the majority of the radiators in the don’t have steam traps. And as far as I can tell, they don’t have special vapor valves either. Thoughts on why they (most of them) appear to be working?

Not challenging your expertise here (you clearly have it and I don’t), just trying to understand my situation better. 

Thanks. 

I started out the same way you did, inheriting an old 2-pipe vapor system that "worked" but not well.  In fact, the pressuretrol settings were the same as your's, non-existent main vents and traps that hadn't been touched since 1931 (none of them worked).

One year later, thanks to this forum: all the radiators heat up quickly and evenly and my fuel bill averages 1/3-1/2 of what it was.  We're lucky this forum exists, there is some serious talent in here that patiently help out us noobs on a daily basis, for free.

I still read the board regularly because I'm always learning things from it.  The tuning never ends.

wilder0m

@Steamhead @Jamie Hall Thank you both. Should I just crank down the pressure all at once, or try in baby steps? And is the vent replacement a DIY job, just screw it on? 

@mattmia2 I checked all the returns when the heat was running. All but two were cool. The two hot ones share pipes, I believe, as they’re bathrooms one directly over the other (I also found a single hot return in the basement). One of those has a steam trap, the other doesn’t. Among the cool returns, most don’t have traps, but one does. 

Jamie Hall

You can do the pressure all at once. Don't be surprised if the boiler turns off sometimes while you are still asking for heat -- that's normal.

Steamhead

wilder0m said:

@Steamhead ..... is the vent replacement a DIY job, just screw it on?

Yes. You'll need a 3/4x1/2" bushing to make it fit the opening, which any plumbing supplier should have.

wilder0m

@guzzinerd Thank you for the words of encouragement! I agree that this board is an incredible community and has already proven invaluable to me. I'm looking forward to getting to your level.

@Jamie Hall and @Steamhead I found one return line that is hot (shared by two radiators that are getting hot, returns are hot coming off both of them). One of these rads has a steam trap (on floor 2), the other one doesn't but I don't know what's inside the elbow (floor 3). Could this be causing problems with steam pressure in the main return line that would affect other radiators? This return pipe is 2nd of 7 (in order of direction back towards the boiler).

Jamie Hall

wilder0m said:

@guzzinerd Thank you for the words of encouragement! I agree that this board is an incredible community and has already proven invaluable to me. I'm looking forward to getting to your level.

@Jamie Hall and @Steamhead I found one return line that is hot (shared by two radiators that are getting hot, returns are hot coming off both of them). One of these rads has a steam trap (on floor 2), the other one doesn't but I don't know what's inside the elbow (floor 3). Could this be causing problems with steam pressure in the main return line that would affect other radiators? This return pipe is 2nd of 7 (in order of direction back towards the boiler).

Absolutely could. And, no doubt, does. You need a functioning trap on that radiator, unless it is a specialty elbow -- in which case you need to be operating the whole system in the ounces per square inch range.

wilder0m

Jamie Hall said:

wilder0m said:

@guzzinerd Thank you for the words of encouragement! I agree that this board is an incredible community and has already proven invaluable to me. I'm looking forward to getting to your level.

@Jamie Hall and @Steamhead I found one return line that is hot (shared by two radiators that are getting hot, returns are hot coming off both of them). One of these rads has a steam trap (on floor 2), the other one doesn't but I don't know what's inside the elbow (floor 3). Could this be causing problems with steam pressure in the main return line that would affect other radiators? This return pipe is 2nd of 7 (in order of direction back towards the boiler).

Absolutely could. And, no doubt, does. You need a functioning trap on that radiator, unless it is a specialty elbow -- in which case you need to be operating the whole system in the ounces per square inch range.

Ok, some new findings. First of all, despite the ~5 PSI setting on the pressuretrol, the boiler doesn't get above 1 PSI; the thermostat shuts it off at 65 degrees first. So I'm guessing reducing the pressure setting won't change much.

Second, I'm now focused on the ground-level wet return line in the basement. It is getting hot--at least the first several feet of it--before even some of the supply lines up into the house are hot. This is a puzzle to me. The wet return line is below the boiler water level. Shouldn't it be full of water? It is connected to the end of the supply main, so evidently the steam is preferring to skip past some of the last few supply branches and go straight to the return at ground level.

I'm guessing this is bad, but what is the likely cause?

Jamie Hall

Well, a wet return should never be more than warm, so something is... odd. How is it piped all the way to the boiler, and how is it connected to the boiler?

mattmia2

The steam is likely passing right through one or more of the radiators with the regular valve instead of the vapor valve on it and in to the return. The pressure may be more than you think it is if you don't have a gauge that is 0-3psi or 0-5 psi on it. That code required 0-30 psi gauge isn't usually accurate in the couple psi range.

Looking at the hodgepodge of radiators either the system was knuckle headed by someone that didn't know what they were doing or it was done by someone that knew exactly what they're doing and there are orifice plates in the radiators with the plain valves (I think there is a metering valve still available new that looks like an ordinary radiator valve).

Since it has a pressuretrol instead of vaporstat and it was cranked way higher than it ever should be my guess is someone bought whatever radiators they could find and guessed on what the correct way to hook them up was.

wilder0m

Jamie Hall said:

Well, a wet return should never be more than warm, so something is... odd. How is it piped all the way to the boiler, and how is it connected to the boiler?

So, the supply main connects to the return main right after the return drops to ground level (after all individual radiator returns feed into it, and after the dry return vent). That is where it gets hot. The entire supply main is hot (as expected) but then the return also gets hot for several feet after the supply connects to it. Are they supposed to be connected there? It seems like steam is being directly fed into the return there. 

After that, the return (what I assumed was the wet portion because it’s at ground level) crosses the basement, then turns vertical upwards again for a few feet right next to the boiler, then connects back to the boiler. I can share more pictures tomorrow. 

wilder0m

mattmia2 said:

The steam is likely passing right through one or more of the radiators with the regular valve instead of the vapor valve on it and in to the return. 

Except the return main isn’t getting hot where the individual radiator returns feed into it*; it’s getting hot where the supply main connects to it at the end. 

*With one exception: there is one radiator return that is getting hot and it’s still warm/hot all the way in the basement where it connects back to the return main. However, it’s only hot right near that connection, not the rest of the return main, until the end where the supply main connects to it. 

Do you have a link to one of these metering/vapor valves that I can ask my contractor about? 

Thanks. 

Steamhead

wilder0m said:

So, the supply main connects to the return main right after the return drops to ground level (after all individual radiator returns feed into it, and after the dry return vent). That is where it gets hot. The entire supply main is hot (as expected) but then the return also gets hot for several feet after the supply connects to it. Are they supposed to be connected there? It seems like steam is being directly fed into the return there. 

After that, the return (what I assumed was the wet portion because it’s at ground level) crosses the basement, then turns vertical upwards again for a few feet right next to the boiler, then connects back to the boiler. I can share more pictures tomorrow. 

The steam main and the dry return should both drop below the boiler's waterline before connecting together. This way, water will stand in the drips (vertical pipes) and steam will not be able to get from one to the other.

Jamie Hall

There should be no direct connection between the steam main and the dry return. Either a water seal and crossover trap, or no connection at all.

mattmia2

Does it drop down before the main connects to the return? This could be a case where either the pressure is too high and pushing the water out of a water seal or the water line of the current boiler is lower than that of the original boiler. It could also just plan be reworked incorrectly since it looks like someone has done a lot of work to modify that system.

reggi

Holy cow .. those radiators look like they came straight from a the bottom of a old scrap pile..in a field.. sorry but you work with what you have.. but everyone is right about the pressure,  those elbows on some of your radiators will let the steam blow right through if your boiler is over 8 Oz or so and your pressurestat looks like it's set almost 10 times that ! ( going by memory) 
Until you get a vaporstat and low pressure gauge you're going to be spinning your wheels with anything that might have to be diagnosed with your system.. think of them a 1930's OBD for your system.. ask me how I know...
Listen to these guys...the Best of the Best.. you won't go wrong.. G/L 

wilder0m

Steamhead said:

So, the supply main connects to the return main right after the return drops to ground level (after all individual radiator returns feed into it, and after the dry return vent). That is where it gets hot. The entire supply main is hot (as expected) but then the return also gets hot for several feet after the supply connects to it. Are they supposed to be connected there? It seems like steam is being directly fed into the return there. 

After that, the return (what I assumed was the wet portion because it’s at ground level) crosses the basement, then turns vertical upwards again for a few feet right next to the boiler, then connects back to the boiler. I can share more pictures tomorrow. 

The steam main and the dry return should both drop below the boiler's waterline before connecting together. This way, water will stand in the drips (vertical pipes) and steam will not be able to get from one to the other.

This is the case. They drop down before connecting. But somehow, right the area of the wet return right after the connection from the main supply is getting hot. Does that mean there isn’t water there and there should be?