Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Help heating my bedroom and sizing my main vent

Hi forum, in Yesterday's post I got a ton of advise and solved a problem I had where my last radiator vent was spitting water. Thank you! Learned a ton and continued to 'dig' today to look for easy improvements.
I have poor piping on this system. I learned yesterday, I have no header and no equalizer see near-boiler piping from yesterday's post) - that's a problem for another day.
I'm looking for help with a few other problems.
1) 8' baseboard style (Fin-single-pipe style) radiator isn't heating the bedroom enough. I think it's 1.5" pipe.
2) Is my main vent large enough? Seems like a pin-hole (see photos). Air whispers out of this so it's working but barely before it closes. I read the vent should be the largest of them all but I'm no steam guy.
3) after removing the 3/4" main vent - I can feel 1" high sludge in the line. I can't imagine how bad this entire main is, any suggestions on (as easy as possible) cleaning this? This system is VERY VERY dirty (see sink photo from yesterday for just a hint of what's inside of my system).
For any idea of my configuration. See a lot of photos in yesterday's post. Also, radiator config is as follows. All good vents and close once steam reaches them.
Radiator config - from first riser off main until last
2nd floor:
1) 2nd floor radiator (bedroom) - vent size "C" - gushes air for a long time - but doesn't stop until steam gets to it (last radiator to heat up by about 30-45 minutes from cold-start). The run goes straight up near chimney, around the chimney to back of house wall into a fin-style single pipe radiator - all behind sheetrock / that I would rather not bust into.
1st floor:
2) Vent size 4 (closest to thermostat)
Radiators 3,4,5 all vent size 5.
Then comes the main vent - see photos from yesterday and closer photos today:


Now that I have this vent off - should I replace it? It works fine - though the air just whispers out of this tiny hole until steam gets to it. Last radiator in line heats up fine, it's the 2nd floor (first one w/vent size "c") that I have the problem with. It's the longest run by far.
Thank you all in advance. Hope this post makes it as I just wrote TWO other ones that seems to have disappeared into a black hole.
I have poor piping on this system. I learned yesterday, I have no header and no equalizer see near-boiler piping from yesterday's post) - that's a problem for another day.
I'm looking for help with a few other problems.
1) 8' baseboard style (Fin-single-pipe style) radiator isn't heating the bedroom enough. I think it's 1.5" pipe.
2) Is my main vent large enough? Seems like a pin-hole (see photos). Air whispers out of this so it's working but barely before it closes. I read the vent should be the largest of them all but I'm no steam guy.
3) after removing the 3/4" main vent - I can feel 1" high sludge in the line. I can't imagine how bad this entire main is, any suggestions on (as easy as possible) cleaning this? This system is VERY VERY dirty (see sink photo from yesterday for just a hint of what's inside of my system).
For any idea of my configuration. See a lot of photos in yesterday's post. Also, radiator config is as follows. All good vents and close once steam reaches them.
Radiator config - from first riser off main until last
2nd floor:
1) 2nd floor radiator (bedroom) - vent size "C" - gushes air for a long time - but doesn't stop until steam gets to it (last radiator to heat up by about 30-45 minutes from cold-start). The run goes straight up near chimney, around the chimney to back of house wall into a fin-style single pipe radiator - all behind sheetrock / that I would rather not bust into.
1st floor:
2) Vent size 4 (closest to thermostat)
Radiators 3,4,5 all vent size 5.
Then comes the main vent - see photos from yesterday and closer photos today:


Now that I have this vent off - should I replace it? It works fine - though the air just whispers out of this tiny hole until steam gets to it. Last radiator in line heats up fine, it's the 2nd floor (first one w/vent size "c") that I have the problem with. It's the longest run by far.
Thank you all in advance. Hope this post makes it as I just wrote TWO other ones that seems to have disappeared into a black hole.
0
Categories
- 80.9K THE MAIN WALL
- 2.5K A-C, Heat Pumps & Refrigeration
- 36 Biomass
- 394 Carbon Monoxide Awareness
- 2.6K Controls
- 1.4K Domestic Hot Water
- 3.7K Gas Heating
- 101 Geothermal
- 130 Indoor-Air Quality
- 2.3K Oil Heating
- 30 Pipe Deterioration
- 567 Plumbing
- 4.2K Radiant Heating
- 333 Solar
- 12.2K Strictly Steam
- 36 Water Quality
- 7 Industry Classes
- 51 Job Opportunities
- 7 Recall Announcements
Comments
"Reducing our country's energy consumption, one system at a time"
Steam, Vapor & Hot-Water Heating Specialists
Oil & Gas Burner Service
Baltimore, MD (USA) and consulting anywhere.
https://heatinghelp.com/find-a-contractor/detail/all-steamed-up-inc
Baseboard is always problematic on single pipe steam, but if it's not banging or gurgling or otherwise, I'd not change its vent. What I might change, though is figure out how to get a vent on the supply pipe as close to the radiator as you can -- a Gorton #1 or D (same thing, different geometry) This may require some ingenuity... but I think if you got that long runout to vent well, it would start to heat sooner and you'd get more heat out of it.
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.
Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
As to the bushing / threads - are you saying a new vent will have different thread sizing? I'll put this one back and deal if that's the case. - This vent was actually unscrewed from main pipe bushing - I don't know if I can unscrew that reducer/bushing.
Anyone ever overfill the boiler to get water into the main to run this crud out?
This may be time for a plumber so I won't have to deal with it.
https://heatinghelp.com/assets/documents/Balancing-Steam-Systems-Using-a-Vent-Capacity-Chart-1.pdf
You can attach multiple main vents at one location. Just put the new vents at the current location.
Is your bedroom baseboard heating up fully?
As for the sediment build up in the main, that's truly amazing that you have that much in a line that's above the waterline. Probably the only ways to deal with it are try to flush it out or cutout and replace that section of pipe. If you try to flush it, you'd have to rig up a way to attach a garden hose as far upstream on the main as possible and hopefully flush it out the drain spigot you have before your hartford loop.
18 Ounce per Square Inch Gauge
Time Delay Relay in Series with Thermostat
Operating Pressure 0.3-0.5 Ounce per Square Inch
Full cleanup took weeks - and now appears it isn't even over.
And yes, I'm VERY glad I had the boiler off when I do this 'trickle feeding'.
Your main should be vented proportionally much faster than your radiators. This promotes the steam to fill the main completely first, and then distribute to your radiators. If you upgrade your main venting, then you can start adjusting the venting on your radiators.
Look at getting a Gorton #2, or even two of them for your main venting.
18 Ounce per Square Inch Gauge
Time Delay Relay in Series with Thermostat
Operating Pressure 0.3-0.5 Ounce per Square Inch
If you look at photo 2 from yesterday you'll see the small pipe running left - this has to go up a full floor around the chimney- and to the back wall of the house from how the photo was taken.
The other (four) 1st floor -radiators only need to run the 6 or 8 feet to the outside walls (my house is only 20' wide by 30' long
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.
Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
I’ll look for a way (might need a plumber) but I would need to remove the baseboard cover. Unscrew the fin pipe (if I can?) and add a vent right before the fins start (doubt the cover would fit back on)
Can you help me understand why a faster vent is a bad idea for this style (provided it closes when steam reaches).
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.
Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
I'd take off the baseboard and see if it's clogged as well.
18 Ounce per Square Inch Gauge
Time Delay Relay in Series with Thermostat
Operating Pressure 0.3-0.5 Ounce per Square Inch
if so, where is the thermostat?
and the rad there,
you would want to slow down that thermostat's rad's venting to allow more boiler run time,
you could even turn that rad off by flipping its vent upside down as a trial.
slow down the venting where there's too much heat, before trying to speed up colder areas.
but, maximize the Main venting first.
All vents are Gorton / maid o mist (Love that I can unscrew the cap to change sizes)
In order from Furnace out -
#1 goes 2nd floor Size "D" vent - 25' riser
#2 to dining room. "Size 5 - 7 foot riser
#3 small office, Size 4 - 9 foot riser
#4 bathroom, Size 4 - 9 foot riser
#5 living room Size 5 - 7 foot riser
Again - ~25' riser behind walls to 2nd floor fin-style bedroom heater is the issue
Update: I placed a "D" vent in the bedroom. And it still takes 20 mins after radiators get hot on first floor for steam to reach it and close. I can hear the vent wooshing plenty of air and keep getting a significant amount of air flowing until steam can get there. but it's too late by that point.
This post -
https://forum.heatinghelp.com/discussion/138343/speed-of-radiator-venting
Talks about a "Starving" radiator condensing and creating a vacuum which may pull steam/air from my bedroom. Does anyone have any further details on this and potential ways to prevent it?
The time of interest is NOT how long it takes for the D vent to close. The time of interest is the time before steam first reaches that radiator and starts to fill it. Depending on the radiator, it may never fill on a normal call for heat. How much time passes between when your first floor radiator gets steam vs when the upstairs one gets steam?
The question is does it heat the room comfortably.
Just did some testing running around my house from a cold start. With the vents as listed above, steam starts to fill the bedroom radiator about 2 minutes after the first radiator starts to get steam so I cannot complain about this at all.
All radiators start to get steam within 2 minutes of each other.
However, it just doesn't heat the room enough. Upstairs (fin style baseboard) is 63 when downstairs tstat is 74. At this point, despite my other thoughts on 'starving radiator pulling steam from upstairs'. I'm going to just believe the unit is just too small and live with blankets until I decide on a replacement.
thanks for all of your help.
like copper fin tube?
could you post a picture?
and a 25 ft riser?
or 25 ft of takeoff from the main?
as Jamie said, you need a fast vent on that riser, before the fintube,
then the slow vent on the tube
@neilc - I guess riser isn't right, I approximate 25' from where it leaves the main to when it makes the last turn in the 2nd floor photo here.
Steam reaches the 'turn' very quickly (about the same time as all other radiators) but the radiator doesn't stay hot for long and then no longer receives enough steam once the 1st floor thermostat gets up to temperature.
The cup isn't needed (no water spitting). I also elevated (using that black piece of metal at end. However, I don't believe it's needed or helped. Tried "D" size fitting on vent as well as a #4 (maid o mist / screw in cap style). Both slow and fast venting still gets steam to the turn quickly but fails to keep the radiator warm all night.
Upstairs 63 downstairs 73
The room is approximately 1500 cubic feet for this pictured radiator.
No surprise there. Copper fin tube has very little thermal mass -- it will heat up quickly, quite true. But -- it will also drop in temperature quickly when the boiler shuts off. And once the thermostat gets up to temperature and shuts off the boiler, that's that. It won't receive any more steam --there's none to receive.
But at least you have it starting to heat almost as fast as the rest of the radiation? That's really the best you can hope for, mixing copper fin tube with cast iron...
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.
Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
So even if you slow down your downstairs radiators, this baseboard might not put out enough heat during the "off" part of the cycles to keep you warm (which is obvious to you as you shiver and is why you wrote).
Tell me: If you were to set your thermostat to 80, would that baseboard get steam hot all the way to the vent?
PS: you didn't ask but if it were my bedroom I'd do a heat loss on it and buy a cast iron radiator to match the BTU loss on Craigslist
it might have the effect of over sizing your boiler a bit because I read through your thread and you already have slow #4 vents on some radiators.
if they are still comparably too hot then you have to start getting creative like throw a folded blanket over part or all of it. Start with the one near the thermostat
Question for the pros. Could they put a gate valve on in place of the 90 degree at the inlet and then raise a air vent off that? Would recommend testing the radiator on a "subsequent cycle" with the existing air vent removed first just to see if it has the capability fully vented to heat up as quickly as the other radiators.
If you're heating steam hot to the vent on the first cycle,
but then only getting that first foot on subsequent cycles,
(and I'm assuming Ptrol cycles while thermostat continues to call for heat)
then is that vent NOT reopening after either being hit with steam, or it's pressure?
what pressure are you up to at the boiler when the Ptrol cycles off?
you might be locking that vent shut till all pressure relieves after the thermostat shuts down.
or,
what if you plumb that vent away from the fin tube heat by a foot or so?
a couple nipples and angles, and get the vent away from the first cycle heat, a foot or so , , ,
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.
Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch