3rd floor not getting heat unless thermostat is cranked

Roos

Hi, I just started perusing these forums last week, so forgive me if there's some etiquette I'm not following.

I'll start with describing the system - I attached a rough MS-paint sketch. It's a Burham IN model in the basement. The house has three floors, and it is a single pipe system. As far as I can tell, it's all original cast-iron piping, same diameter throughout. There is one thermostat, and that is on the first floor. There is a radiator in the same room as the thermostat, which is somewhat problematic. The first and second floors get heated relatively easily/quickly.

Next, the problem: I live on the third floor, and the heat doesn't seem to reach us up here (unless we crank the heat. Eventually the heat DOES reach some radiators on the floor, if the burner runs long enough...) Each radiator on the 3rd floor seems to have its own problems, I'll describe that in a bit.

Here's what I tried so far, and here's what I'm considering... first, I read that the pressuretrol should be set at 1.5 psi main, and 0.5 psi diff. Mine was set at 5 psi main, so I changed that to 1.5 psi main - but I don't think it did anything, because while the gas burner is firing, I don't see the pressure gauge climb at all, so in other words, I believe the only control in this system is the thermostat. Next, I read that there needs to be a good main vent close to the boiler. I found it, and it seems to be original, which would put it at 80 years easy. Not sure if it works. What does this vent do?

So, now to some specifics. The 3rd floor bathroom radiator doesn't get anything, though I do hear some hissing from its vent. The kitchen radiator gets very little heat. Today, I found the 2nd floor bathroom radiator's steam vent cracked - maybe that explains why the 2nd floor bathroom gets so hot? We removed it, and replaced it with a similar valve I found (not new).

The living room radiator seems to work the best when the heat is cranked. It spewed a bit of water out of the steam valve. The bedroom radiator spewed A LOT of water, so I shut the main valve off. I assumed the valve was faulty, so I replaced it with a Varivalve, and water spewed out of this one, as well. Once again, I shut the main valve off, and moved the Varivalve to the living room radiator, as I'd like to get that one to work first. I did notice that the radiator in the "room" that feeds the living room and bedroom is 1) very small and 2) gets VERY hot. Should I try putting a smaller steam vent on it?

Other notes: there is water hammering going on for the bedroom/living room radiators temporarily, when first heated. The bedroom radiator pipes + radiator do appear to be slanted as to allow water to escape, so I'm not sure why there's so much water in that part of the system. Also, when I first moved up here to do work, I found the pipe leading to the bedroom cracked clean in half, so I replaced that. A cylinder of frozen water fell out of the cracked pipe. This led me to believe that the pipe wasn't levelled properly, so I shimmied the pipes to allow water to escape.

Sorry about the rant-like nature of this, hope you guys can help!

KC_Jones

As far as the heat not getting where you want it, that is almost always a venting/balancing issue. The vents on the mains allow the air out of the pipes, where there is air the steam can not go. The vents on the rads serve the same purpose, but are only to vent the rad and the pipe leading to that rad. The rule of thumb is vent the mains in the basement fast and vent the rads slowly. In your case you put as much main venting as you need on the basement pipes. You put the smallest vents on the first floor, slightly larger on the second and possibly slightly larger on the third. The idea is ALL rads get steam at pretty much the same time. You need to look at the entire system at once, nut just one room at a time. Also you need a solid baseline. If it was mine I would look at either replacing all the vents with new fixed size vents sized accordingly or getting some good adjustable vents for all the rads. Maid O Mist has a kit with different orifices, there is also the Hoffman 1A adjustable, personally I like Gorton and they are fixed non adjustable. Before any of that you really need to get the main venting in order. The rule of thumb is 1 Gorton #2 vent for each 20' of 2" main. Also I suggest you get the balancing steam book from the store here. It's 10 bucks and goes to charity. Great read and fantastic information.
http://store.heatinghelp.com/Balancing-Steam-Systems-p/300.htm

Jamie Hall

Couple of other items. The actual valves -- not the vents -- at the inlets to one pipe steam system radiators must be left open. Partly closed they trap water, and completely closed they can still leak some steam -- and then trap water. You might check on that and make sure.

Second, pipe pitch is really critical. This may be a problem with the living room radiator, which puts out a lot of water. Is there, perhaps, a horizontal run under the floor which doesn't drain properly? If it's only slightly out, it would hammer -- but if it's really out, it can block steam almost completely.

Your change in pressure setting was the right thing to do. That the pressuretrol doesn't seem to do anything is just fine, so long as the radiators get steam. It's there to limit the maximum pressure.

nicholas bonham-carter

I see from your diagram that there are two horizontal runs, from the risers, on the top floor. If those radiators served by them are having problems, then try to raise up the rads with quarters, with more quarters under the vent end . This may repitch the horizontal under the floor.
You need adequate main venting, as has been said, and slow radiator vents, as the resistance of air escaping must be balanced on the risers so that the mains fill first, (because of low resistance main vents), then the risers to the rads begin to fill all at the same time. This will help all of the rads to see steam simultaneously, and you will be warm on the third floor finally!
You could have a wired/wireless sensor on the third floor to make sure there is a minimum temperature up there for finer control.--NBC

moneypitfeeder

"but I don't think it did anything, because while the gas burner is firing, I don't see the pressure gauge climb at all"

I would suspect a clogged pigtail, which is easy to remedy, and should be done. Your controls should work. (Shut the boiler down first!) Then, try to remove the pig and run a piece of metal like a straightened coathanger through it till it clear and re-install. Then see if you get any movement in your pressure gauge. You might also want to pull the pressure gauge and clean up the opening, then blow into it to see if the needle deflects at all. It may be clogged as well...

KC_Jones

It's good to check and verify everything is clean, but just to be clear on a 0-30 PSI gauge you honestly don't want to see it move. Excess pressure is bad in any steam system and you want it as low as possible. The OP could have a well matched boiler that just doesn't make pressure which is a good thing.

Roos

Thank you all for the replies and information!

KC_Jones said:

In your case you put as much main venting as you need on the basement pipes. Maid O Mist has a kit with different orifices, there is also the Hoffman 1A adjustable, personally I like Gorton and they are fixed non adjustable. Before any of that you really need to get the main venting in order. The rule of thumb is 1 Gorton #2 vent for each 20' of 2" main. Also I suggest you get the balancing steam book from the store here. It's 10 bucks and goes to charity. Great read and fantastic information.
http://store.heatinghelp.com/Balancing-Steam-Systems-p/300.htm

I'll take action as follows.
1) I'll replace the main vent, and look into perhaps adding more main vents. It's a fairly large system hooked up to 17 radiators. Probably will go with Gorton for this one.
2)I'll probably go with Maid O Mists from 1st to 3rd floor, sized according to their chart. Is Mr.Supply a reputable place to buy this stuff?

Jamie Hall said:

Partly closed they trap water, and completely closed they can still leak some steam -- and then trap water. You might check on that and make sure.

Second, pipe pitch is really critical. This may be a problem with the living room radiator, which puts out a lot of water. Is there, perhaps, a horizontal run under the floor which doesn't drain properly? If it's only slightly out, it would hammer -- but if it's really out, it can block steam almost completely.

Your change in pressure setting was the right thing to do. That the pressuretrol doesn't seem to do anything is just fine, so long as the radiators get steam. It's there to limit the maximum pressure.

3) I didn't know that closed valves can still cause problems. I will keep the valves open from now on. Follow-up question: there are some radiators in the house that are not in use. How do you close them off? Is there some kind of plug that I can put on the radiator in place of the vent?

4) Yes, there's definitely a horizontal run under the floor for the bedroom and living room space. I will raise the radiators in an attempt to correct any potential pipe leveling issues.

nicholas bonham-carter said:

...try to raise up the rads with quarters, with more quarters under the vent end . This may repitch the horizontal under the floor.
...
You could have a wired/wireless sensor on the third floor to make sure there is a minimum temperature up there for finer control.--NBC

5) I'll definitely double check the pitch of all radiators on top of raising them.

6) The wireless sensor is an interesting idea, but I don't want the lower floors to cook. On the other hand, this thread seems to be all about balance, so maybe with a properly balanced system, the primary thermostat will be sufficient.

moneypitfeeder said:

I would suspect a clogged pigtail, which is easy to remedy, and should be done. Your controls should work. (Shut the boiler down first!) Then, try to remove the pig and run a piece of metal like a straightened coathanger through it till it clear and re-install. Then see if you get any movement in your pressure gauge. You might also want to pull the pressure gauge and clean up the opening, then blow into it to see if the needle deflects at all. It may be clogged as well...

7) I'll leave this last on my to-do list, but this is a good point. There's another problem I didn't mention - whenever I drain some water from the boiler, it's always rusty/dirty. Is it supposed to be clean? Should I just shut off the boiler, drain the its entire contents, and re-fill? As far as cleaning the boiler itself goes -- how often should that be done? For this part, I think I'd rather hire a professional.

I'll post a follow-up when I begin to do some work maybe later tonight or over the weekend.

Fred

To close off an unused radiator, simply turn the vent upside Down. That will prevent air from escaping the radiator and steam from getting in. Leave the supply valve open.

KC_Jones

I would ask the question what do you hope to accomplish with shutting down a radiator? If you think you will save, I would rethink it. The room is still putting load on the house, so that cold room will suck the heat out of the warm rooms and essentially act as a heat sink. Also closing off radiators essentially oversizes the boiler and will contribute to short cycling the boiler (added wear and tear). You should get the entire system balanced with everything on, then maybe consider shutting down a radiator. If you leave them shut down and balance the system, then turn them back on someday that will most likely throw the system back out of balance. As far as main venting it isn't how many radiators it's how much piping there is. The only way to get it right is to measure the length of all the mains and their size. If you do that and post the information we can help you out. Unless the system is really tiny you will definitely need more than one main vent per main so I would plan accordingly. Oh and if there is even a tiny suspicion of a dirty or clogged pigtail that should be top on the to do list. That is a safety device and it is very important. If it isn't working the only device you have to limit the pressure is the safety relief valve, trust me you don't want to be around if that thing pops open at 15 PSI.

vr608

KC_Jones said:

If it isn't working the only device you have to limit the pressure is the safety relief valve, trust me you don't want to be around if that thing pops open at 15 PSI.

Agreed, assuming it still even is functional.

Roos

KC_Jones said:

I would ask the question what do you hope to accomplish with shutting down a radiator? If you think you will save, I would rethink it. The room is still putting load on the house, so that cold room will suck the heat out of the warm rooms and essentially act as a heat sink. Also closing off radiators essentially oversizes the boiler and will contribute to short cycling the boiler (added wear and tear). You should get the entire system balanced with everything on, then maybe consider shutting down a radiator. If you leave them shut down and balance the system, then turn them back on someday that will most likely throw the system back out of balance. As far as main venting it isn't how many radiators it's how much piping there is. The only way to get it right is to measure the length of all the mains and their size. If you do that and post the information we can help you out. Unless the system is really tiny you will definitely need more than one main vent per main so I would plan accordingly. Oh and if there is even a tiny suspicion of a dirty or clogged pigtail that should be top on the to do list. That is a safety device and it is very important. If it isn't working the only device you have to limit the pressure is the safety relief valve, trust me you don't want to be around if that thing pops open at 15 PSI.

Sounds scary! I'll check the pigtail first chance I get.

There are 2 radiators I want to shut off as they are storage rooms. Then there are two more unused rooms with a radiator each. So you're saying that those rooms are actually costlier to keep off than on? I guess I'll run a test. I'll try to pick two relatively similar cold days, and record the amount of natural gas in cubic feet used with and without the unused radiators running. Or maybe a week. Hard to test, lots of variables.

I need some clarification on what constitutes a 'main'. Those are all the steam pipes in the basement, right? Or does that include runs of piping inside the walls as well? I believe the pipe diameter is the same throughout the house @ 2".

KC_Jones

I'm not saying it will cost more. The savings could be negligible or even non existent, but it will make the boiler short cycle since you have change the size of the system it is attached to. Just because you aren't using a room doesn't mean the house ignores it. Unless you fully insulate the room and totally isolate it from the house it is still load on the heating system in some way or form. To me you would be better off putting very small vents on them to minimize the heat, but still keep some heat in there so it isn't dragging down the rooms around it. Just my opinion. The mains are the pipes connected directly to the boiler. so follow those pipes to the end, this is NOT counting the branches running directly to radiators off the main just the main pipe feeding those branches.

Fred

The Mains are the pipes that start at the horizontal header above your boiler and run out across or around the basement. All the radiator run-outs are feed off of that main(s). Once you find the last radiator run-out on the main, the main either ends and has a drip leg on it that drops to the floor or the main becomes a Dry return that may continue a few feet before it drops down into a wet return (a line that is below the water line in the boiler and carries water back into the boiler).

Jamie Hall

The only comment I'd add to the insulation -- sometimes long radiator runouts, even serving just one radiator, can really benefit from insulation.

Roos

Oh boy. I am pretty irate.

So I placed a Maid O' Mist #4 on the 2nd floor bathroom radiator that feeds my bathroom + kitchen, and I did start hearing a lot more hissing, at least out of the kitchen radiator. Then I discovered it was pitched the opposite way, so I corrected it, and it's getting some heat under normal conditions! It's been unseasonably warm lately, so I'll find out what the real deal is a bit later. But then I discovered a water leak coming from the ceiling of the second floor bathroom... uh oh. I decided to pry open the drywall in my 3rd floor bathroom to see what that pipe is doing exactly, because I suspected there was a water trap. Lo and behold, check out the picture.

The radiator in the bathroom has a water trap. The pipe goes down into the floor, then comes back up out of the floor where the radiator is. I can't believe the previous construction workers thought this was a good idea. It's basically a giant 'U' with several elbows.

My plan is to continue this pipe and just have it go exposed in the closet before the radiator, and insulate it. So far I've taken my angle grinder to it... I think I'll just leave that old pipe to hang out for all eternity, and have it think about what it has done.

I suspect a similar situation for the living room and bedroom. This'll take some work. The adventure continues!

BobC

In the winter that will add much needed humidity; shame it's not to the space that could use some extra humdidity.

Bob

Roos

Found and fixed the living room + bedroom trap. That was painful. Whoever worked on this house previously sure did some strange and/or dangerous things. Living room works great now! I'll be moving on to balance the system next.