Over Venting the Mains? Weak heat to 2nd floor. Please reAD.

tumbz

I have a steam boiler that has 2 main runs. Each main is about 30-40 feet to the end. On the end of each main has a 3/4 nipple with a big mouth vent on each. Im thinking about making an antler and adding another big mouth, making it 2 big mouth vents for each of the 2 mains....

would that be over venting???

The reason im doing this is because my first floor heats sufficiently and satisfies the thermostat before my 2nd floor is fully heated. The 2nd floor radiators has large capacity air valves and the 1st floor has all the air valves closed to the lowest so they heat up slower...

But the 2nd floor still heats only.half way when the cycle shuts.down...

Would venting the mains more help.in my situation???

Thanks for your help.

tumbz

I have a steam boiler that has 2 main runs. Each main is about 30-40 feet to the end on 2 inch pipe. On the end of each main has a 3/4 nipple with a big mouth vent on each. Im thinking about making an antler and adding another big mouth, making it 2 big mouth vents for each of the 2 mains....

would that be over venting???

The reason im doing this is because my first floor heats sufficiently and satisfies the thermostat before my 2nd floor is fully heated. The 2nd floor radiators has large capacity air valves and the 1st floor has all the air valves closed to the lowest so they heat up slower...

But the 2nd floor still heats only.half way when the cycle shuts.down...

Would venting the mains more help.in my situation???

Thanks for your help.

Jamie Hall

Venting the mains more won't help with the balance problem -- you've got enough (although, to be fair, it's almost impossible to over vent a main... ).

What air vents are you using on the radiators? Some variable vents don't close down all that far. And some are, oddly, too fast. On the upstairs radiators, do they heat across the top and close the vent before the whole radiator is warm, by any chance?

Fred

How close is your thermostat to a radiator? It may be that the thermostat is being satisfied before the rest of the house reaches set point. If that's the case, slow the venting even more on the near by radiator.

tumbz

all the radiators on the first floor has the same hoffman a1 vents. THey are all closed!!! I turned them down to the closed setting o the radiators heat slow.

The upstairs radiators, i have maid o MIST size D vents which are supposed to be the FASTEST venting valves.

But even doing this, only half the radiator gets hot upstairs on a regular cycled. FOR EXAMPLE, if i leave the boiler on for AN extra 10 minutes after the thermostat has been satisfied , then the upstairs radiators will fully be heated.


Do i need to tap the upstairs radiators to add ANOTHER air vent to vent faster?

tumbz

the thermostat is on the first floor, and i did closed all the vents on the first floor so they vent slower, giving the 2nd floor a chance to catch up with the faster vents upstairs.

but even doing so, the upstairs only heats halfway during a regular cycle. Should i tap them to add an addition aIR vent ????

ChrisJ

Those Hoffman 1As are hard to adjust

The numbers do not mean anything. There's too much slop in the lid. Remove the nut on one and you'll see what I mean.

tumbz

Yes ur right chris, but i adjusted it so that they cover the hole and then held it down and tightened it..... I am almost sure they are pretty closed...

I guess i can just try to close a few radiators by the BALL VALVE and let it run a regular cycle to test if the upstairs gets heated all the way?

tumbz

@ChrisJ do you know of a better vent? How about those vent rite #1?

ChrisJ

No, do not close the valves.

I like Gorton vents but they're not adjustable.
You could try a few G4s on the first floor and G6s on the second floor and see how it does.

G5 is a good "normal" vent. 4 is really slow 6 is fast C is really really fast.

I would start with 4s and 6s and go from there.

Danny Scully

Vent-rites are great too, and adjustable.

Fred

Do you have a programmable thermostat? If so, is it set for "Steam" at 1CPH? They come from the factory set at 5CPH for forced air. It may be that the boiler isn't running long enough to get the radiators hot. Also, in most cases, radiators won't heat all the way across unless it is really cold outside and the boiler runs for a long time. It's the room temperature you should be trying to balance.

gfrbrookline

I am thinking @Fred is on the correct path. Is the upstairs comfortable temperature wise? If not and the thermostat is satisfied before the upstairs heats the thermostat is likely in the wrong location or set to the wrong CPH.

From my experience a MoM D is way too aggressive for almost all radiators. I have a three story 6 unit condo building and started out thinking that more venting would help cool units, after a couple of years of trial and error I found the opposite to be true. The largest radiator vent I have is a Gorton 6 on a large 8 fin 36" high radiator on the third floor, I tried a D on it and it only heated on the sides and top, the center was always room temperature and the room got cooler. All of my vents are Gorton 4's and Vent rite #1's, had bad luck adjusting Hoffman 1A's.

As far as the mains, the main vents basically vent the the mains so if the heat is equally distributed on the first floor your main venting is fine.

STEAM DOCTOR

Might not be a venting problem. Could be a wet steam problem. Wet steam will die the future it travels.

tumbz

I think i should move my thermostat but if i move it upstairs, the first floor will be too hot!

tumbz

i just checked my CPG. its at the slowest settings also.

tumbz

im going to try the danfoss thermostatic valves on the rads closest to the thermostat so that it heats up last, giving the upstairs more run time before the cycle shuts down.

THANKS GUYSSSSSSSSSSSSSSSSS ill report back

ChrisJ

> @tumbz said:
> im going to try the danfoss thermostatic valves on the rads closest to the thermostat so that it heats up last, giving the upstairs more run time before the cycle shuts down.
>
> THANKS GUYSSSSSSSSSSSSSSSSS ill report back

No you do not want a txv near the thermostat!

Just get a few Gorton 4s and go from there.

John Ruhnke

Steam moves fast! Very fast! It takes seconds to travel to the tenth floor of a ten story building.

It shouldn't take ten minutes to get steam to the second floor. Something is not designed correctly. Could be uninsulated piping or backpitched piping with some trapped condensate. To small a steam boiler? or Header? Wet steam? Clogged or undersized piping? Thermostat could be short cycling the boiler? Or the air doesn't get out fast enough.

There is a problem that hasn't yet been solved. If you solve it the second floor radiators will heat just as fast as the first floor ones.

tumbz

@John Ruhnke I insulated all the piping on the mains and around the boiler.

My mains are 2 inch piping with 3/4 inch pipings teeing off to the first and 2nd floor rads.

I changed both my main vents with big mouth vents, changed the pigtails, flushed my system, everything looks good and works well.

Its just that the thermostat turns off since the first floor reaches the set temp before the 2nd floor gets fully hot. I guess thats the nature of a 1 pipe steam system.

I dont know what else to do. I already put large venting air valves up stairs to try to get the steam there faster.

The only other thing left to do is to slow down the heat on the first floor by the THermostat so the boiler runs 5-10 minutes longer to fully heat the 2nd floor. Im guessing my only other air vavlve choice is danfoss thermostatic vavles, since i can turn it all the way down..??

What do you think?

tumbz

@ChrisJ why not danfoss? Im thinking that if i try the gorton 4, and it still heats too fast, ill be out of luck and still need to buy a danfoss?

ChrisJ

> @tumbz said:
> @ChrisJ why not danfoss? Im thinking that if i try the gorton 4, and it still heats too fast, ill be out of luck and still need to buy a danfoss?

The idea of a TXV is to control a radiator by room temperature. The venting still needs to be correct.

That said, the last thing you want is a radiator that can control it self, even totally shut off being the main one that effects the thermostat.

John Ruhnke

Check to see if the boiler is undersized.

size a replacement boiler by counting all the radiation in the house. The total becomes the net EDR (equivalent direct radiation) rating of your replacement boiler. Steam doesn’t care about heat loss or anything else–only the amount of the length of piping. If the boiler is too small, part of the building will never heat; if it’s too big, the new boiler will short cycle, consume more energy and require more service calls.

Sometimes large radiators require adding a extra vent. Drill a hole half way down the radiator under the first vent, tap it and add a second vent.

Trying to diagnose a steam system from my house is difficult. If I was there at your house I would easily be able to find the problem by looking over the whole system. I am a low temp hydronics guy. There are some really great steam guys here on the wall. They know more about steam then I do. Check out "Find a Contractor" and invite one of those great steam guys to visit. I am sure they will spot something that you and I aren't thinking of right now.

ChrisJ

> @John Ruhnke said:
> Check to see if the boiler is undersized.
>
> size a replacement boiler by counting all the radiation in the house. The total becomes the net EDR (equivalent direct radiation) rating of your replacement boiler. Steam doesn’t care about heat loss or anything else–only the amount of the length of piping. If the boiler is too small, part of the building will never heat; if it’s too big, the new boiler will short cycle, consume more energy and require more service calls.
>
> Sometimes large radiators require adding a extra vent. Drill a hole half way down the radiator under the first vent, tap it and add a second vent.
>
> Trying to diagnose a steam system from my house is difficult. If I was there at your house I would easily be able to find the problem by looking over the whole system. I am a low temp hydronics guy. There are some really great steam guys here on the wall. They know more about steam then I do. Check out "Find a Contractor" and invite one of those great steam guys to visit. I am sure they will spot something that you and I aren't thinking of right now.

If radiators are stealing steam you slow them down you don't replace the boiler unless it's an extreme case.

I've got a boiler rated for 325sqft connected to 392sqft and it's fantastic. I'd never go back to the larger size.

Right now the OP needs to fix his venting before attacking everything at once. One step at a time.......

John Ruhnke

@ChrisJ
You said
"If radiators are stealing steam you slow them down you don't replace the boiler unless it's an extreme case.

I've got a boiler rated for 325sqft connected to 392sqft and it's fantastic. I'd never go back to the larger size.

Right now the OP needs to fix his venting before attacking everything "

The op shut down all the air vents on the first floor and he still can't get enough steam to the second floor. That is impossible. Unless something isn't right. The op is missing something, The radiators should get hot in minutes. They do on my steam jobs.

John Ruhnke

@tumbz

You Said
"Its just that the thermostat turns off since the first floor reaches the set temp before the 2nd floor gets fully hot. I guess thats the nature of a 1 pipe steam system."

No that isn't true. In 90% of the jobs I go to the second floor gets hot faster than the first floor. Unless something isn't right.

Is there a big radiator next to the thermostat? Cause that would cause that problem too. If that radiator got hot fast. Proper location of the thermostat is important. Or shut that radiator 100% off.

ChrisJ

> @John Ruhnke said:
> @ChrisJ
> You said
> "If radiators are stealing steam you slow them down you don't replace the boiler unless it's an extreme case.
>
> I've got a boiler rated for 325sqft connected to 392sqft and it's fantastic. I'd never go back to the larger size.
>
> Right now the OP needs to fix his venting before attacking everything "
>
> The op shut down all the air vents on the first floor and he still can't get enough steam to the second floor. That is impossible. Unless something isn't right. The op is missing something, The radiators should get hot in minutes. They do on my steam jobs.

If the boiler is hot and the mains are hot I can get steam to all 10 radiators in 90 seconds and they all get steam within a few seconds of each other.

John Ruhnke

Is the thermostat mounted to a wall with the chimney in it?

tumbz

@John Ruhnke its mounted on the wll in the living room right in the middle about 5 feet off the ground. There are 3 radiators nearby...

Im thinking about trying to shut those down and run a regular cycle to see if thatll help my upstairs. If it does, ill just buy some slow venting valves... Maybe try the gorton 4 or danfoss thermostatic valves.

@ChrisJ thanks guys for trying to help. Im listening to all suggestions.

JUGHNE

You said you have 2" mains with 3/4" taps for first and second floor radiators.....that sounds small. Are you sure of those sizes?

John Ruhnke

@tumbz

You said
"There are 3 radiators nearby"

Once the radiators get up to temperature then it is about the ratio of the heatloss. So here is what looks like the problem Room A has 3 radiators and is 300% oversized as heatloss goes. Rooms B C and D average 100% heatload. Even though B,C and D are properly sized with the thermostat in room A the thermostat shuts off as soon as room A gets warm. A heats up 3 times quicker than any other room. So the thermostat shuts off too early. The heat doesn't stay on long enough to heat the other rooms. The solution is to reduce the heating in room A by completely shutting off one radiator and reducing output with a slow flowing steam vents on the other two. You have to reduce the load of room A to 100% then the thermostat will stay on longer to heat the other rooms.

John Ruhnke

It is all about balance. If one room is 150% and another room is 100% sized you need to achieve balance. You either need to decrease the load in the first room or increase the load in the second room. I usually find it easier and cheaper to decrease the load from 150% to 100% than to increase from 100% to 150%.

Of course if one room has 25% of the required load you need to increase that room. But I find 95% of the systems to be oversized so that is rare.

Fred

This is puzzling to me @tumbz . Is this a 1 pipe or 2 pipe system? From the way you describe the venting on your mains and on each radiator, I have to believe it is a 1 pipe system but then you say the run-outs to the radiators are 3/4" pipe. If that's the case, a 3/4" pipe may have the capacity to carry 15 or 20 EDR of steam and allow condensate to also return. Any radiator larger than a small 15 or 20 EDR radiator (typically used in small bathrooms) won't heat all the way across, no matter how you vent them.

ChrisJ

> @Fred said:
> This is puzzling to me @tumbz . Is this a 1 pipe or 2 pipe system? From the way you describe the venting on your mains and on each radiator, I have to believe it is a 1 pipe system but then you say the run-outs to the radiators are 3/4" pipe. If that's the case, a 3/4" pipe may have the capacity to carry 15 or 20 EDR of steam and allow condensate to also return. Any radiator larger than a small 15 or 20 EDR radiator (typically used in small bathrooms) won't heat all the way across, no matter how you vent them.

I missed that....
Yeah what's with the 3/4" piping?

John Ruhnke

3/4 piping does sound small for a one pipe system.

JUGHNE

Could we see pictures of your piping take offs; also some of the
boiler piping showing floor to ceiling?

What pressure does the boiler run at?

Is there a chance you have a 2-pipe air vent system?
Pictures of both ends of your radiators would be good.

tumbz

@JUGHNE OK PICTURES coming now. Im just guessimating the main pipe size, im not a plumber. I said the run offs from main were 3/4 because the big mouth air vent i connected to it is a 3/4th. HAHA. Mains are probably 3 inches, and the run offs, im not too sure, but here are pics of everything!

tumbz

Im sure i have a 1 pipe steam system.

***1) This is pic of my radiator teeing off my main. I think main is a 3 inch and the run off is a 1 inch???



***2) Here are pics of my boiler.






***3) THESE ARE BOTH MY ENDS THAT I CHANGED TO BIG MOUTH VENTS, BARNES AND JONES.

tumbz

my basement is finished so i had to look for my mains. HAHA.
Luckily i found them both on first shot. Hard part was taking off old valves in such a small space..

@JUGHNE boiler runs at low pressure, about 1.5. Pressuretrol is at .5 and 2.

@John Ruhnke
@Fred
@ChrisJ

John Ruhnke

The mains and branches look fine. That header is way undersized though.

Fred

@tumbz , That main looks like maybe 2". The radiator run-outs look to be 1". Are all the run-outs, including the ones to the first floor radiators the same size or are the first floor run-outs 1.25"? Typically 1" Run-outs can support about 28 EDR of steam, which is still a fairly small radiator. They need to be pitched well to get the most out of them. From the looks of that piping, did someone re-pipe the mains and radiator run-outs at some time and did they down size any of the piping? Can you see where the vertical pipe goes up to the second floor? Is the vertical pipe larger?