Heat on one side of the house only

davert

I am truly puzzled by this - we have one-pipe steam, with two major branches of the boiler, installed in 1928. The boiler was replaced 14 years ago by an older, very well experienced plumber, with a 60,000 BTU Peerless cast-iron unit. It runs with a vaporstat set to 10 ounces. The system worked very well until this year. It's unchanged from the past.

Now, only one side of the house gets steam (from branch #1). The other side does not. The vent valves are working. If I take one of the vent valves off completely, and wait a while, I can get some steam, so it's not totally blocked, but even if I max the vaporstat to 16 oz, one side of the house whistles and the other side is cold.

I ran a snake down through the vertical part of the return, and it's clear and dry. It was set up so water going to the boiler flushes out the dogleg, and there wasn't any unusual mud in there.

The boiler is short-cycling, with half the radiators available. THe plumber, for whatever reason, put valves into the two steam branches, and I can shut off the working one—and then the other one will get steam, and all the radiators heat up nicely. Then it short-cycles even more... and I can't really go down there and pull the valve every two hours.

Any ideas? I can't help but think there's a block somewhere, but either side works... and the return pipe hasn't moved, and “appears” with a level to have an ever-so-slight correct pitch down to the boiler. While troubleshooting, the original plumber also added air valves to the returns, about two feet in, adding to the original return air valves. Those work. However, agian, under normal conditions, the cold side's return doesn't get warm — no hot water's coming down. Again, shut off the “hot” side, and suddenly the cold side's return works fine.

I can supply pics if needed, but if you have any thoughts or diagnostics, I'd love to hear them.

BobC

has anything happened that may have changed the slope of the main that isn't heating? It sounds like you have water pooling in a pipe and that will kill the steam traveling over it. The same would happen if a belly has occurred along that main (maybe the main has sagged over the years) - anything that might pool water has to be found and fixed.

Bob

Long Beach Ed

Has anything changed the output, or rather the input of the boiler? Is the burner working correctly? An underfired boiler can do this and the steam will favor the easiest side... Once it condenses, it sets up a vacuum and steam continues to favor that main. Make sure your main vents are working too. A boiler sized with marginal output will again favor the easiest main.

CantabHeat

Out of curiosity is the main that normally heats the first on that comes off the header as you follow the flow of steam through the header?

As indicated above if for whatever reason steam starts going down one main off the header first it create create its own vacuum and suck more steam behind it starving the other main.

If the steam starts coming out slowly vs in one big burst it may just go into that first heater and then suck more steam after it. The fact that you get steam by closing the valve to the other main implies something like this.

Venting is of course key too but if for whatever reason you start pulling a vacuum in one main and if that’s the first one coming off the header then I’ve seen strange stuff happen where stream will refuse to go down an open pipe off another main. No amount of venting will overcome that vacuum in the other main. These are finicky beasts.

As a fix I once saw someone build a little box with a small fan in it like those used to cool computer chips. They then places that around the vent on the cold main. This created a tiny amount of negitive pressure that pulled steam into the cold main. It looked a bit sillily and was unorthodox but it totally worked and fixed their balancing issue in ways traditional venting was not able to.

Hap_Hazzard

This is where it's useful to have king valves, so you can shut of the side that's working and see if the other side gets hot or if it just makes the Pressuretrol cut out.

Barring that, can you get to the main vents? If you tape over the vent ports on the good main, see if that makes the other main start working. Listen for gurgling and banging noises.

If you can't reach those vents, all you can do is try feeling the cold main to see how far the steam gets.

You say you have a 60,000 BTU Peerless model, but I don't see one with a rating that low. Can you tell us the model number?

Where are you located?

davert

First, thank you for your quick responses.

1) I probably have the BTU rating wrong. The house piping is relatively small, though. It takes about 45 to 60 minutes from cold to steam. “ Make sure your main vents are working too. A boiler sized with marginal output will again favor the easiest main.” I think it's been favoring the easier main for years, but the other side did get _some_ heat.

2) “ It sounds like you have water pooling in a pipe and that will kill the steam traveling over it. The same would happen if a belly has occurred along that main (maybe the main has sagged over the years) - anything that might pool water has to be found and fixed.” — I was thinking that, but I have no way to test it. Nothing has happened that I know of, but houses settle, even after 90 years. Everything “looks” the same, that I can see, but I can't see behind walls. The parts of the main and return that I can see are tilted correctly—the return is _barely_ tilted, though.

3) “Out of curiosity is the main that normally heats the first on that comes off the header as you follow the flow of steam through the header?” — Absolutely!

“If the steam starts coming out slowly vs in one big burst it may just go into that first heater and then suck more steam after it. The fact that you get steam by closing the valve to the other main implies something like this.”

Yes...

“Venting is of course key too but if for whatever reason you start pulling a vacuum in one main and if that’s the first one coming off the header then I’ve seen strange stuff happen where stream will refuse to go down an open pipe off another main. No amount of venting will overcome that vacuum in the other main. These are finicky beasts.”

I wonder if I reducing the venting to that side would help—I've increased venting to the other side... that's my next trick. The fan seems beyond my capabilities.

4) “This is where it's useful to have king valves, so you can shut of the side that's working and see if the other side gets hot or if it just makes the Pressuretrol cut out.” Shutting the king valve does both; the system short-cycles but it does heat the other side _very_ quickly.

5) “If you can't reach those vents, all you can do is try feeling the cold main to see how far the steam gets.” It seems to get into the main, but these are heavily insulated pipes. It doesn't get as far as the return pipe or vents, unless, as noted, I shut off the other side with the king valve.

I think CanTab Heat and Long Beach Ed may have the solution; I'll do a little empirical testing and get back to you. You ALL have my thanks. (I'll also grab the boiler model.)

Gsmith

Are there any very aggressive (fast) vents on radiators connected to the main that gets steam. If there are, these too can cause the steam to favor that main by creating a vacuum in the radiator and preventing steam flow to the other side of the house. You could try slowing down the radiator vents on the side of the house that gets the steam. I have seen this happen when there was a really fast vent (happened to be a Heat-timer varivalve that caused the steam to go to one larger radiator to the point that even removing the main vent on the side of the house not getting steam did not get the main hot through a 3/4" tapping.

STEAM DOCTOR

Clock your gas meter. Possible that gas valve is bad and not letting in enough gas. Result is small fire and not enough steam to go around.

acwagner

Did this get progressively worse or was an abrupt change from working to not working?

Also, are your mains insulated? I found it's really difficult to spot a belly or poor pitch in a pipe that is insulated.

CantabHeat

Yes, you could try reducing venting on the fast main and radiators and that will likely help. However that usually only works from a fresh cycle start. Once steam starts condensing and drawing a vacuum it’s usually game over until the next cycle. You can either change vent types of depending on type you can carefully place a piece of tape partially across the hole to reduce the air flow. Gently blowing into the vent is a low tech way of feeling how much air is going to come out of that vent.

Good luck and let us know how things go.

Agree it does sound like maybe the boiler isn’t producing enough steam and that should be looked at too, but these other tricks are also worth trying and are basically free. You can time the gas meter and get a good idea of how many BTUs of gas per hour are being used when the boiler is firing.

davert

Gary Smith said:

Are there any very aggressive (fast) vents on radiators connected to the main that gets steam. If there are, these too can cause the steam to favor that main by creating a vacuum in the radiator and preventing steam flow to the other side of the house. You could try slowing down the radiator vents on the side of the house that gets the steam. I have seen this happen when there was a really fast vent (happened to be a Heat-timer varivalve that caused the steam to go to one larger radiator to the point that even removing the main vent on the side of the house not getting steam did not get the main hot through a 3/4" tapping.

Yes, but when I closed off the vents entirely on the favored side of the house... it still got steam and the other side stayed cold. It just short-cycled a lot. It was a good and useful experiment!

STEAM DOCTOR said:

Clock your gas meter. Possible that gas valve is bad and not letting in enough gas. Result is small fire and not enough steam to go around.

I think that's a good theory, but it steams in around the same time that it used to, suggesting that's not the issue.

acwagner said:

Did this get progressively worse or was an abrupt change from working to not working? Also, are your mains insulated? I found it's really difficult to spot a belly or poor pitch in a pipe that is insulated.

It was progressively worse, I think, leading to a more sudden lack of ANY heat at all on one side.

The mains are very well insulated with fiberglass (by professional insulators), but the returns aren't, and I'm thinking maybe one return might be the culprit, since it's barely tilted.

CantabHeat said:

Yes, you could try reducing venting on the fast main and radiators and that will likely help. However that usually only works from a fresh cycle start. Once steam starts condensing and drawing a vacuum it’s usually game over until the next cycle. You can either change vent types of depending on type you can carefully place a piece of tape partially across the hole to reduce the air flow. Gently blowing into the vent is a low tech way of feeling how much air is going to come out of that vent.



Good luck and let us know how things go.



Agree it does sound like maybe the boiler isn’t producing enough steam and that should be looked at too, but these other tricks are also worth trying and are basically free. You can time the gas meter and get a good idea of how many BTUs of gas per hour are being used when the boiler is firing.

Thanks. I'll time the meter since two people suggested it. Also, I did tape up the vents but maybe I didn't let it get cold enough first...? It was between cycles. I can try again tomorrow when it's warmer and I can shut it off longer without it going nuts trying to regain heat.

Thank you all for sticking with me. If this doesn't work, I guess my next step is getting a plumber in to adjust that return, which will involve replacing a short connecting pipe (and probably a little plaster demolition).

Hap_Hazzard

Make sure you find someone with good knowledge of steam. Did you say where you're located?

Fred

Have the Gas company come out and check that the line into the house is open and that their pressure at the meter is correct. We've seen this happen several times by other posters here. If everything on your steam system worked before, I'd be inclined to make sure the Main vents are working and I wouldn't change anything else on the system until I was 100% certain the fuel supply to the boiler is as it should be. Any other "tampering" you do to your system will only mean you have to go back and try to adjust things back to the way they were, if the fuel supply is the culprit.

davert

Hap_Hazzard said:

Make sure you find someone with good knowledge of steam. Did you say where you're located?

Northeast NJ by Hackensack - happy to get a recommendation.

Main vents are absolutely working fine.

Will check fuel use next. It IS a new gas meter... oops, which is now outside. I'll still go out and measure, if it still has dials...

Long Beach Ed

New gas meter??? Take a pressure test at the gas valve and you may find for problem!

If you have high pressure distribution, the supplier has a pressure reducer at the meter which may have been changed and may be providing lowered pressure, which would result in low firing...

Icarus

davert said:

Hap_Hazzard said:

Make sure you find someone with good knowledge of steam. Did you say where you're located?

Northeast NJ by Hackensack - happy to get a recommendation.

Main vents are absolutely working fine.

Will check fuel use next. It IS a new gas meter... oops, which is now outside. I'll still go out and measure, if it still has dials...

Ding, ding, ding! Do we have a winner?

A pretty good axiom that I live by when things go south...”what has changed?” It may not be gas delivery/pressure problem, BUT...if that is the only thing that has changed, it ought to be the first thing to check...

Let us know.

Icarus

BobC

A few years back my power gun fired gas boiler started making more noise than usual. Knowing that others on the street had problems with their gas supply I put a manometer on the gas meter and the gas pressure was dropping by 1.5" when the boiler fired. I called the gas company and they sent someone out who confirmed bad gas pressure, he tried reaming the incoming pipe but it was not enough. The next day at 0730 a backhoe was digging up the street to install new pipe, by 1800 the gas was back on and steady as a rock.

As to possible sags in steam mains, stretch a string along the pipe - the will quickly reveal sags in the main.

Bob

Hap_Hazzard

Someone from the local gas company told me that it's not unusual for the gas line to rust out underground between the meter and the house and that the gas pressure is so low that it doesn't cause a leak, nor is it enough to keep the ground from gradually collapsing until it shuts off the supply. I assume you'd notice a drop in pressure before that.

davert

They replaced the gas line because it had rotted out. I don't know why I assumed everything would be hunky-dory. I wonder if some grit in the lines made it into the burners... but would that explain why half the valves in the house can be hissing and the system from overpressure, while the second line is still sitting there, waiting for heat?

Jamie Hall

davert said:

They replaced the gas line because it had rotted out. I don't know why I assumed everything would be hunky-dory. I wonder if some grit in the lines made it into the burners... but would that explain why half the valves in the house can be hissing and the system from overpressure, while the second line is still sitting there, waiting for heat?

No. There is some other problem in there which is blocking -- or at least slowing -- steam to that side of the system. Have your gone all along the length of that steam main to find out just how far the steam is getting, and how fast?

Hap_Hazzard

Maybe not, but it's something that needs to be checked periodically anyway.

davert

Jamie Hall said:

There is some other problem in there which is blocking -- or at least slowing -- steam to that side of the system. Have your gone all along the length of that steam main to find out just how far the steam is getting, and how fast?

I've tried but the fiberglass doesn't help. It doesn't get to the start of the return. It gets to the radiator on the first floor but not to the second-floor bathroom (which is an earlier pipe, but higher up).

BTW, I counted 1 minute, 8.8 seconds for four rounds of the 1/2-foot dial, which works out to 34.4 seconds/foot, which is 34,400 BTU — which is well under what I'd expect. Is it time to call the gas company? It's funny, everything else seems to work fine. I guess the only thing that _really_ consumes gas is the boiler.

The return has a very slight grade, but the main (at least what I can see of it; a ceiling hides it on the far side of the house) has a good enough grade that I can't believe it's the problem. The return could well be getting clogged with water, though.

Hap_Hazzard

davert said:

BTW, I counted 1 minute, 8.8 seconds for four rounds of the 1/2-foot dial, which works out to 34.4 seconds/foot, which is 34,400 BTU — which is well under what I'd expect. Is it time to call the gas company? It's funny, everything else seems to work fine. I guess the only thing that _really_ consumes gas is the boiler.

34.4 seconds/ft³ is about 105 ft³/hr, which is about 105,000 BTUH. Does that sound more reasonable?

(BTW, I only know this because I recently clocked my meter. I'm not that smart.)

Jamie Hall

I seem to recall from somewhere up above that you can block or at least reduce the flow in the one side which does heat properly? Would make it easier.

In any event, what you need to do at this point is trace along the main which is not heating and find out how far the steam gets. If there is a vent on the far end of that main, so much the better. Undo it (have someone at or near the boiler to turn it off it steam gets that far). Now. Fire up the boiler. With the vent off, you know air can get out of one end of the main. If the steam doesn't get there, there is something blocking the main. A water pocket... who knows. But something. Trace along the main and find it.

Fred

I think you mentioned you have a king valve on each Main. Have you checked to make sure the problem main king valve is open?

JUGHNE

When your new meter was installed outside, did the length of pipe to the boiler increase by any considerable amount?

And what is the input rating of the boiler...from the nameplate?

Jamie Hall

I agree that there may be a firing rate problem.

However.

The fundamental problem is that there is something amiss with the steam feed on that one side. Should not be hard to find -- there aren't all that many possibilities -- but find it you must.

Then go chasing after the burner rate problem, if there is one.

Long Beach Ed

Trust me, the main isn't clogged. It's a firing problem.

Jamie Hall

Um. Well, OK I guess. What I'm reading looks like a significant imbalance -- for reasons which we do not know yet -- between the two mains. But if that's a firing problem, so be it.

gfrbrookline

What vents do you have on all of your radiators? Please list cold side/warm side and the size of the radiators they are connected to.

I had a similar problem in my building years ago. Turned out one side of the building had slower vents than the other, also had a clogged main vent, which made the steam favor the faster vented side.

davert

Hap_Hazzard said:

davert said:

BTW, I counted 1 minute, 8.8 seconds for four rounds of the 1/2-foot dial, which works out to 34.4 seconds/foot, which is 34,400 BTU — which is well under what I'd expect. Is it time to call the gas company? It's funny, everything else seems to work fine. I guess the only thing that _really_ consumes gas is the boiler.

34.4 seconds/ft³ is about 105 ft³/hr, which is about 105,000 BTUH. Does that sound more reasonable?

I can't believe it's that high... but maybe... .

gfrbrookline said:

What vents do you have on all of your radiators? Please list cold side/warm side and the size of the radiators they are connected to.

I had a similar problem in my building years ago. Turned out one side of the building had slower vents than the other, also had a clogged main vent, which made the steam favor the faster vented side.

Cold side: started with all Varivalves. Due to exerimentation: one Maid-O-Mist without the screw-in restrictor, two VariValves. There is also a big radiator that's usually taped over. I get heat on it if I untape it; it's right over the boiler.

Hot side: two taped-over Gortons (a huge radiator in a room that doesn't need the heat), two regular small Gortons (first floor), two VariValves (second floor).

As you may have guessed, one issue is the distribution of radiators in the house is not appropriate to the rooms. The bedrooms have relatively small units and the main floor has very large units. One solution I plan to pursue in the summer is redoing the blown-in insulation, installed 30 years ago. Basically, though, the goal is the same temperature in every room. The living room area has two massive radiators, the sun porch (smallest room in the house) has the largest radiator that will physically fit, and the dining room (which has the thermostat) has yet another large one.

I might have been the cause of the short-cycling with the taping over, but I've been living with this arrangement for over ten years, and it never short-cycled before.

Progress: I noticed that the water level was high (probably because of the distance from the sight glass to the mark) and dropped it by around an inch. I now get “steam is coming” noises (air coming from the steam valves) from the cold side, but still little to no actual heat. Also, I'm trying to get someone in just after Christmas to drop that one return which almost certainly has at least one level or incorrectly tilted section. I don't know why that would have changed over time, but I think it must have...

Long Beach Ed said:

Trust me, the main isn't clogged. It's a firing problem.

So... time to have someone in to check the burners? If I'm really using 105,000 BTU, I don't think there's a pressure issue.

JUGHNE said:

When your new meter was installed outside, did the length of pipe to the boiler increase by any considerable amount?

And what is the input rating of the boiler...from the nameplate?

Boiler 63-04, installed 11/2005. 177.0 input. Requires 1/2 psi or lower input.

Jamie Hall said:

I seem to recall from somewhere up above that you can block or at least reduce the flow in the one side which does heat properly? Would make it easier.

In any event, what you need to do at this point is trace along the main which is not heating and find out how far the steam gets. If there is a vent on the far end of that main, so much the better. Undo it (have someone at or near the boiler to turn it off it steam gets that far). Now. Fire up the boiler. With the vent off, you know air can get out of one end of the main. If the steam doesn't get there, there is something blocking the main. A water pocket... who knows. But something. Trace along the main and find it.

I am getting steam from the final part of the return in the slow side, in gasps and puffs, when I take the vent off entirely.

JUGHNE

When you clock your meter you should come up with close to 177,000 btuh.......you are short a fair amount if you only clock 105,000.

Did the piping change for the gas line......longer pipe.....smaller pipe installed?

Jamie Hall

Getting steam in gasps and puffs tells me there's water lying in there somewhere. Keep after it.

davert

JUGHNE said:

When you clock your meter you should come up with close to 177,000 btuh.......you are short a fair amount if you only clock 105,000. Did the piping change for the gas line......longer pipe.....smaller pipe installed?

I'm pretty sure the boiler itself is rated at 105,000 or less. Same size inside the house; under the street, who knows?

Jamie Hall said:

Getting steam in gasps and puffs tells me there's water lying in there somewhere. Keep after it.

Thanks. That would explain much. I can take off any valve on the cold side of the house and get puffs of air, but even without the valve, it only gets warm while the other side gets hot. Under the insulation, I "think" I can trace the heat but not very far; planning on getting an infra-red thermometer to test further.

The short cycling really does indicate water, doesn't it? I mean, if it was underfired, would it short-cycle from pressure?

Hap_Hazzard

davert said:

If I'm really using 105,000 BTU, I don't think there's a pressure issue.
…
Boiler 63-04, installed 11/2005. 177.0 input. Requires 1/2 psi or lower input.

JUGHNE said:

When you clock your meter you should come up with close to 177,000 btuh.......you are short a fair amount if you only clock 105,000.

Did the piping change for the gas line......longer pipe.....smaller pipe installed?

@davert, your input is 40% low. That's quite a lot. You could have someone check your manifold pressure and try to adjust it, but I'd be inclined to call the gas company first so they can check your service.

Fred

@Hap_Hazzard said: " @davert, your input is 40% low. That's quite a lot. You could have someone check your manifold pressure and try to adjust it, but I'd be inclined to call the gas company first so they can check your service. "

In suggested that about 30 posts ago. I don't know why it is so hard to have the gas company check the meter, line and pressure. They don't charge for that.
Also @davert , no the short cycling does not indicate water. If there is water sitting in the main, the steam would condense just like it would if it made it to the radiators and any steam that could get past the pooled water would still head towards a radiator.

Hap_Hazzard

It never ceases to amaze me how you guys can see things from your experience that I have to do all kinds of math to figure out.

JUGHNE

The spec sheet/boiler ratings for the 63-04 is lying on my desk.
177,000 input, for the purpose of this problem/discussion the other numbers do not matter.

You have to shovel enough gas into this boiler to get it to perform. And you said the label says 177,000 input. How can you be sure the boiler is rated at 105,000 or less. The label rules what this boiler should burn. (true some have been modified, but not yours).

You are trying to start a car with no gas in the tank.
Get it running before putting new tires on it.

If you get the correct firing rate then perhaps these other issues you have everyone suggesting have always been there but you produced enough steam to overcome these symptoms.

The gas company is responsible to deliver gas at a certain pressure at normal flows. They should check that.
When they installed a new UG service/meter to your house they most certainly have an adjustable gas pressure regulator there.
It may be set too low. All of your other gas appliances may perform just OK with inadequate pressure, you may never notice.

You are responsible to provide adequate piping to the boiler and adjust the gas valve to deliver the necessary pressure to the burner manifold.
You could have any one of these above issues and perhaps plugged burner nozzles.

You mentioned setting your vaporstat, but do you have a 0-3PSI gauge on the boiler? The vaporstat numbers may not be correct, you need an accurate gauge to check it with.

BobC

You are just throwing things at the wall till you know what pressure gas is being delivered, somebody has to put a manometer on the output of the house gas meter. If that is ok, do the same at the boilers gas valve. That would tell you if the pipe size between the gas meter and the boiler are large enough - make sure all other gas appliances are firing when you do this.

Bob

dennis53

Gary Smith said:

Are there any very aggressive (fast) vents on radiators connected to the main that gets steam. If there are, these too can cause the steam to favor that main by creating a vacuum in the radiator and preventing steam flow to the other side of the house. You could try slowing down the radiator vents on the side of the house that gets the steam. I have seen this happen when there was a really fast vent (happened to be a Heat-timer varivalve that caused the steam to go to one larger radiator to the point that even removing the main vent on the side of the house not getting steam did not get the main hot through a 3/4" tapping.

Perhaps replace the Varivalves with slower vents as suggested?
I've had the same experiences as Gary.

clammy

Does the working main have a lot of radiator on it while your hard to heat has just a few . If so you may have excess venting on one side causing a steam main distrubition issue due to major differences in amount of air is being vented by each main and it’s radiator vents collectively in a few cases I have removed the faster mains main vents and used a smaller vent like a straight gorton #6 and Shebang all was good in the universe and all fell into balance . I have seen this issue and the first time it threw me for a loop . I would suggest to trash those Varivents And pick up some some good vents either Hoffmann 1a if you go the adjustable route or some non adjustable gorton vents . If tight on money go buy some maid o mists and use them to properly balance your system then replace w the proper gorton vents . Just wondering how’s your boiler piping and is your piping insulated ,these two items are quite important to a properly performing steam system with out either one you waste energy ruin vents and do not have proper comfort . Peace and good luck clammy