Steam two pipe Radiators not heating properly , some weird sounds

JoshP

I have a two pipe steam system . Pipes and radiators original to house installed late 1920s, current American standard boiler probably early 60s. I’ve got the system working pretty darn well almost silent when operating . The Issue I’m having is two second floor radiators in two different bedrooms (adjacent to each other) at opposite end of boiler (boiler in the basement) have always sounded like off and on gushing water maybe some might call it panting (heavy breathing )in the vertical supply steam pipes running up through the walls to those two radiators. I’ve replaced the traps at those radiators and also made sure they were pitched to drain condensate properly. I’ve read it could be debris or water “stuck” in the supply pipe causing a reduced flow or small blockage. Those two rooms are generally considerably cooler than the rest of the house. The t stat will generally shut off at set point before those two radiators get full of steam. No banging or knocking from the vertical pipes. Any thoughts or remedies ? Thanks 

Jamie Hall

Look for a horizontal, or near horizontal, section of piping either in the supply or in the return common to those two radiators which isn't pitched adequately to drain.

Is there a main vent or crossover trap on the main feeding these two?

JoshP

Jamie Hall said:

Look for a horizontal, or near horizontal, section of piping either in the supply or in the return common to those two radiators which isn't pitched adequately to drain. Is there a main vent or crossover trap on the main feeding these two?

The rads in question are in separate room (rooms are adjacent to each other) and on separate supply and return lines. One is east side other is west side . No crossover or common vent or trap other than main Vent for system near the boiler . two rads on the second floor opposite end of the house which happen to both be in our master bedroom cook us out. I’ve got the valves opened only 1/2 turn. Pitch of supply and return seems ok. 

neilc

can you post a picture of one of the trouble makers,
actually, 2, one of each end showing as much supply or return pipe as possible

JoshP

neilc said:

can you post a picture of one of the trouble makers, actually, 2, one of each end showing as much supply or return pipe as possible

They are basically a mirror image as far as how the supply and return are. But here are some pics. 

JoshP

The supply and return are on the same side on both rads. Don’t think that makes a difference but thought I would note it if you see the pics and are wondering. 

neilc

ok,
i meant to see the radiator, and as much pipe as possible,
and now I'm really interested,
are the rads vented at the far end ?

JoshP

neilc said:

ok, i meant to see the radiator, and as much pipe as possible, and now I'm really interested, are the rads vented at the far end ?

No vents at the rads. Both pitched at least 1/4 bubble to return . Both have covers. I have replaced the trap elements with new ones.  Also note someone before me replaced the valves with non steam type but the ones in my bedroom also have non stream type valves and doesn’t stop them from heating up the room. 

neilc

the working rads, are they piped the same way? both pipes at the same end like these?

Are the returns under the none working traps hot? steam hot?

Jamie Hall

neilc said:

ok,
i meant to see the radiator, and as much pipe as possible,
and now I'm really interested,
are the rads vented at the far end ?

Two pipe with traps, @neilc .

Can you get enough of the insulation off to check the pitch of the horizontal parts of the runouts? They may be flat enough to hold some water -- though not enough to hammer.

neilc

@Jamie Hall said:

neilc said:

ok,
i meant to see the radiator, and as much pipe as possible,
and now I'm really interested,
are the rads vented at the far end ?

Two pipe with traps, @neilc .

yeah, but, uh,
ok, steam in the top, pushes air out the bottom,
I'm just having problems seeing the far end clearing its air,
maybe the supply valves need to be throttled down ?

JoshP

Jamie Hall said:

ok, i meant to see the radiator, and as much pipe as possible, and now I'm really interested, are the rads vented at the far end ?

Two pipe with traps, @neilc . Can you get enough of the insulation off to check the pitch of the horizontal parts of the runouts? They may be flat enough to hold some water -- though not enough to hammer.

Yes pitch looks at least 1/4 bubble in proper pitch on supply and return 

JoshP

neilc said:

the working rads, are they piped the same way? both pipes at the same end like these? Are the returns under the none working traps hot? steam hot?

There is only one other rad on first floor with supply and return on same side of the rad. That one works fine. To your second question the two in question the steam supply lines are hot. If you put your hand in the pipe you can feel the pipe vibrating when the boiler is on in my opinion like the steam is trying to push through something. The Back and forth I mentioned. Also these two are only heating up about the top 1/4 of the rad before the boiler cycles off under a normal cycle period.  So not much heat coming off them. 

JoshP

I will also mention when we first bought the house my FIL not realizing it was a steam boiler opened up the fill valve because the boiler was drained and off and began to fill the system with water. I had water leaking out of the rad connections on the second floor. Not sure how much water was added but I subsequently drained the system to correct water level . This was 10 years ago. 

I’ve replaced the trap element and adjusted the pitch since then. 

veteransteamhvac

I would try loosening the union at the trap on a radiator and observing it during a heat cycle to see if you get steam to the radiator quicker. Be ready, obviously, to catch any condensate and escaping hot steam and end the cycle. But this will tell you at least if the issue lies downstream in the return or if you're not getting sufficient steam to the radiator.

mattmia2

Did those radiators ever heat properly after the system was flooded?

The supply and return on one end should be fine because the steam will rise to the top of the radiator and move across then down pushing the air down so it should fill just fine.

Remember if a trap is failed open it doesn't keep the radiator it is on from heating, it potentially keeps other radiators from heating because the steam in the return blocks air from venting through the return and potentially gets to the outlet of other traps and closes them.

JoshP

mattmia2 said:

Did those radiators ever heat properly after the system was flooded? The supply and return on one end should be fine because the steam will rise to the top of the radiator and move across then down pushing the air down so it should fill just fine. Remember if a trap is failed open it doesn't keep the radiator it is on from heating, it potentially keeps other radiators from heating because the steam in the return blocks air from venting through the return and potentially gets to the outlet of other traps and closes them.

I can’t speak to before we bought the house I’m the system was drained and not working when we closed on it. I had to bring it up to speed. But I would say they never have heated properly since we first got in the house. I did have a guy helping me get the boiler working and it up to speed and we pulled the traps out on one of them and cycled it and I don’t think that helped them heat up so I’m inclined to think the blockage is in the supply? We also added small rad air vents and that didn’t seem to help either. I’ve since removed those vents because it’s my understanding two pipe steam systems don’t need them and shouldn’t need them. 

JoshP

veteransteamhvac said:

I would try loosening the union at the trap on a radiator and observing it during a heat cycle to see if you get steam to the radiator quicker. Be ready, obviously, to catch any condensate and escaping hot steam and end the cycle. But this will tell you at least if the issue lies downstream in the return or if you're not getting sufficient steam to the radiator.

Ok. If I open the union next to the trap if the blockage is in the return line the steam steam should heat rush through the radiator without the panting struggle back and forth I hear in the supply currently.. is that correct ? 

mattmia2

Is the return pipe cold?

You're not thinking like steam. If air can't get out, steam can't get in. If steam heats a steam trap it will close, it doesn't care if it comes from the supply or the return. If steam encounters more than a small amount of water, that water will absorb the heat of the steam and the steam will collapse back in to liquid water. Most "blockages" in steam systems are not solid objects but air, steam, or water.

pedmec

I would take the cage trap cover off of the trap and remove the cage unit. Just have some one at the boiler to shut it off when ready. This way if you do have a failed trap causing the problem you will most likely see it coming thru the trap. If radiator heats and no steam at return trap shut radiator valve off and wait. It might come a little later. This will help with determining a supply or return issue

JoshP

mattmia2 said:

Is the return pipe cold? You're not thinking like steam. If air can't get out, steam can't get in. If steam heats a steam trap it will close, it doesn't care if it comes from the supply or the return. If steam encounters more than a small amount of water, that water will absorb the heat of the steam and the steam will collapse back in to liquid water. Most "blockages" in steam systems are not solid objects but air, steam, or water.

Hi yes when i said blockage I was meaning water in the pipe. I’ll check next cycle on how hot return gets. I know I cycled it with out the trap element in with the cap off and I think it still didn’t seem like the steam was moving any faster in the supply. I’ll have to try it again to be sure because that was several years ago . If it happens to be water sitting in the supply pipe how to I go about removing it? Also why would both rads on separate lines be acting the same ? 

Jamie Hall

Water sitting somewhere -- and it doesn't have to be a full pipe, could just be an extended puddle -- is all about pitch. Consistent pitch. There are recommended slopes for pipes -- but even if it isn't quite right, it probably will work -- provided there are no, and I do mean no, low spots or sags.

JoshP

Just checked returns on both after a longer heat cycle. The traps are pretty warm but returns in basement are maybe room temp. Warmer than ambient temp in basement but not hot. 

I’ll work on opening up the trap and seeing what happens. 

mattmia2

Are these off of the main in about the same location? Is this the end of the main or are there more radiators past this? What happens at the end of the main to get rid of air and condensate?

JoshP

mattmia2 said:

Are these off of the main in about the same location? Is this the end of the main or are there more radiators past this? What happens at the end of the main to get rid of air and condensate?

These are the last two rads off the mains for second floor. The mains continue to two more rads on the first floor. There are two sets of main supplies and main returns each set running on each side of the basement. It all vents through a main vent near the boiler. 

JoshP

pedmec said:

I would take the cage trap cover off of the trap and remove the cage unit. Just have some one at the boiler to shut it off when ready. This way if you do have a failed trap causing the problem you will most likely see it coming thru the trap. If radiator heats and no steam at return trap shut radiator valve off and wait. It might come a little later. This will help with determining a supply or return issue

I pulled cover of trap and pulled the element out . Ran the boiler with it open while watching it . The supply still was off and on fighting to get to the rad. Having the cap and element out didn’t seem to fix it. So it would seem like the horizontal supply line to this rad needs to have the pitch corrected? Other than jacking up the rad is there another way to correct it? 

JoshP

Any suggestions here ? I disconnected both supply and return lines from one of the problem rdas. Was able to get both about 3/4” higher by pushing up on the lines from the basement . This increased the positive pitch of the horizontal lines before the run up inside the wall to the rad. It didn’t seem to help. Also why are both sides of the system , the two mirror image rads in question,  acting the essentially the same way as described above? 

neilc

maybe the water belly is closer to the boiler ?
have you posted any pictures of questionable piping?

JoshP

neilc said:

maybe the water belly is closer to the boiler ? have you posted any pictures of questionable piping?

The two first floor rads that run off the main and are beyond the problems ones on that are on the second floor have no issues . so I’m thinking the water blockage must be in the area where these two second floor rads branch off the main? Pics of the East side rad piping. The branch coming off for the second floor is the horizontal pipe in front of the main wood beam. 

neilc

ok, so, after the riser and return leave the basement, and shoot up the first floor to the second,
what's happening up there?
are there horizontal laterals before supplying the 2 rads?

and on the blue and black diagram, or as I read,
we're talking about 2 different rads,
on 2 different risers and returns,
and the 2 riser sets are fed from 2 different mains in the basement?

JoshP

neilc said:

ok, so, after the riser and return leave the basement, and shoot up the first floor to the second, what's happening up there? are there horizontal laterals before supplying the 2 rads? and on the blue and black diagram, or as I read, we're talking about 2 different rads, on 2 different risers and returns, and the 2 riser sets are fed from 2 different mains in the basement?

I’m having the same issue with Two separate second floor rads. Two diff risers, two diff returns, same issue. They branch off the main and return that is on their side of the house (So two mains and two returns each having their own radiators branching off for their respective side of the house that their main/return is on. ) they basically mirror each other the way the are piped. once the verticals runs up through the wall it connects to the rad. No horizontal piping once it’s in the wall to the second floor that I can see . But it may have a short horizontal leg in between floor joists since it goes up in between the wall in the basement but comes up through the floor in the bedroom to connect to the rad as seen in pic. Supply/Return connects as in pic below  

neilc

I'm stumped,

is the boiler firing its fullest?
out of tune, under fired?
does it make pressure on the gage?

for giggles, try closing valves on the working rads, and see if steam reaches these 2 naughty rads,

same vein, open the union on the supply valve(s), run boiler,
got steam ?

that near boiler piping, is not correct, = wet steam ?
dirty water? = wetter steam?
and those 2 basement laterals are just wetting and collapsing the steam delivery,

maybe they need to pitch down to the risers, and add @Jamie's crossover traps, to the dry returns

veteransteamhvac

If you try neilc's suggestions above of turning off the other radiators' supply valves and then find you get heat to the cold radiators then I would wonder if perhaps you have too much main venting or valve issues at the suspect radiators or some of the steam quality issues mentioned above.

mattmia2

If you turn off another emitter and other emitters that weren't heating start heating, on 2 pipe steam, it is steam passing through those emitters that are now closed and in to the returns and keeping those emitters that weren't heating from venting. It is possible that it could be underfiring/sizing of the boiler, inlet restrictions for a trapless system on some bot not all of the emitters, or condensate from the working emitters blocking the return that doesn't drain right.

JoshP

mattmia2 said:

If you turn off another emitter and other emitters that weren't heating start heating, on 2 pipe steam, it is steam passing through those emitters that are now closed and in to the returns and keeping those emitters that weren't heating from venting. It is possible that it could be underfiring/sizing of the boiler, inlet restrictions for a trapless system on some bot not all of the emitters, or condensate from the working emitters blocking the return that doesn't drain right.

I’ll try closing down the two second floor rad valves and see what happens. I did open the union at the trap and took the cap off the trap and cycled the boiler. I didn’t get any steam out of the return and having the union open didn’t help with the flow of steam to the rad. So that seems to be it’s a supply problem . The non steam style valve at the rad I don’t think could be causing all this but should it be changed to be sure ? I did confirm it is opening. (Or appears to be from looking into the open end and feeling the stop inside. 

mattmia2

Lets see. If you get no air or steam out of the open valve not connected to the radiator then it is the supply. Try taking the bonnet off the valve make sure both haven't fallen apart inside the valve. Since it was flooded there could be debris in each runout trapping water although it is a lot more likely in the return or a one pipe with the valve at the bottom. You could try pouring like a bucket of water down the supply.

neilc

JoshP said:

I’ll try closing down the two second floor rad valves and see what happens. I did open the union at the trap and took the cap off the trap and cycled the boiler.

to be clear,
I was suggesting shutting off radiators that are working, to force steam to the 2 that are not working,
or maybe as others are saying, (and I agree with), maybe a "working" rad is passing steam thru it's trap, and fouling the returns of the non working rads,
and second, to eliminate or prove the fouled returns theories,
I would open the union at the supply valve to the non working rad(s),
run the boiler, and see that steam does, or does not pass thru the supply valve, this becomes another good time to confirm the valve is open, and not failed closed internally.

JoshP

mattmia2 said:

Lets see. If you get no air or steam out of the open valve not connected to the radiator then it is the supply. Try taking the bonnet off the valve make sure both haven't fallen apart inside the valve. Since it was flooded there could be debris in each runout trapping water although it is a lot more likely in the return or a one pipe with the valve at the bottom. You could try pouring like a bucket of water down the supply.


 

To be clear the rads are heating up to some degree but minimally and usually only about 1/2 of the top of the rad is hot before the system cycles off. And as noted there is lots of noise from the steam trying to get through to the rads. 

Today to took off the shut off valve at one of the problem rads. Inspected the valve and there are no issues with it. Opens fully no restrictions. I poured a small amount of water down the open supply. Then I used my small portable air compressor to shoot some compressed air in the pipe. My luck I popped the fuse in the air compressor before I could really get much air in the pipe. So I restored to blowing in the pipe myself. I’m getting puff back of air as is there is a restriction in the pipe. Considering I’m blowing in the pipe and it’s a second floor riser and still get air blown back at me does that mean I’ve got a pool of water or something more in the pipe restricting the pipe flow ? Shouldn’t the supply be open back to the boiler and just fill with the air i blow in? 

mattmia2

It could be either. Try like a gallon of water. If it is trapped water it will pour through. If it is debris it will fill up the pipe.

My strong suspicion is that there is a lateral in the supply below the floor that has the wrong pitch

JoshP

mattmia2 said:

It could be either. Try like a gallon of water. If it is trapped water it will pour through. If it is debris it will fill up the pipe. My strong suspicion is that there is a lateral in the supply below the floor that has the wrong pitch

Thanks. I used my larger garage air compressor and ran my hoses in through the window and pushed a good amount of air through the supply. Will see what happens when it fires up again. 

neilc

it will be ok until the condensate pool forms again,
where's that low spot?