Leaking air vents on steam baseboard raditors and banging noise in pipes

lovinglife

Sept 12, 2022 - Replaced several leaking air vents over the previous two years in my 1st floor steam baseboard radiators in the living room and back bedroom and had loud banging noises in the pipes. The same air vent in the bathroom baseboard steam radiator never leaked.

A plumber told me I had the wrong type of air vents and replaced them with what he said are the correct type. This stopped the leaking air vents, and reduced but did not totally eliminate the banging noises.

March 7, 2023 - new air vent leaking in back bedroom and loud banging noise. Did not replace air vent because I planned to replace baseboard with free standing radiator

March 14, 2023 - another plumber estimated $ to replace each baseboard radiator with free standing radiator and sealed small leaks in supply valves to the 1st floor steam baseboard radiators in the back bedroom and living room

Nov 16, 2023 - 1st floor baseboard radiator steam air vents are not leaking. Still banging noise in pipes.

Jan 4, 2024 - a plumber repaired a leak in a steam pipe in the basement. After that, the air vent in the 1st floor back bedroom steam baseboard radiator started to leak and the banging noise got louder. This steam baseboard radiator also takes longer to heat up than the other baseboard steam radiators on the 1st floor.

I replaced the air vent to stop the leak. The banging noise continues to be loud.

I'm currently reading Dan's "We Got Steam Heat".

I'm now aware that I need insulation on the main pipes in the basement. I'm also not sure where the main air vents are located. I will have a plumber address these two items.

I have not had these issues with the free standing radiators on the 2nd floor.

I'd love to hear thoughts on replacing the 1st floor baseboard steam radiator with a free standing steam radiator and about ways to eliminate the loud banging noises.

Thanks in advance

ethicalpaul

I'm now aware that I need insulation on the main pipes in the basement.

You don't need insulation. It won't help your banging. Replacing vents won't help your banging. There is water either getting pushed into your system, or being left behind in your system where it doesn't belong.

Jamie Hall

Also... in addition to @ethicalpaul 's comment. What pressure is the boiler operating at? And what vents are you using?

lovinglife

ethicalpaul said:

I'm now aware that I need insulation on the main pipes in the basement.

You don't need insulation. It won't help your banging. Replacing vents won't help your banging. There is water either getting pushed into your system, or being left behind in your system where it doesn't belong.

Thanks for the feedback

lovinglife

Jamie Hall said:

Also... in addition to @ethicalpaul 's comment. What pressure is the boiler operating at? And what vents are you using?

Thanks for the response. The boiler operates between 2.5 - 5 psi.

Attached is a photo of the air vent that was leaking and the one I replaced it with

Waher

Boiler shouldn’t be operating above 2psi.

cut in of 0.5 to cut out of 1.5 psi is what the boiler should be set to in order to avoid problems. 

Radiator vents do not last long above 2psi. 

If the system won’t heat unless the pressure is set over 2psi, then there are other problems which need to be addressed immediately.

BobC

A "C" vent is a fast vent and that type of convector is usually happiest with lower vent rates because of all the condensate the convector produces. Are the other convectors venting at that same rate?
You can get vent kits that come with a vent and 5 different vent orifices for that single vent, this lets you dial in the correct venting rate.
Generally you want to vent the mains slowly and the radiators slowly. Keep in mind this is a heating system and it has to be balanced so it comes up to heat at about the same time.

Bob

clammy

Steam heat w baseboard convector is a slippy slope as it really isn’t the best choice and usually there’s always some splitting at some point in time . As for other suggestion that insulation doesn’t matter well after close to 40 years doing this I tend to completely disagree but then I do this for a living so by all means listen to another home owner who does not do this for a living Diy ? If you want the truth then look for some one who is versed in steam heating this may or may not be a plumber . Baseboard convector are not the ideal convector for steam a free standing radiator will operate far better . Personally I don’t even entertain the talk of installing copper ,steel or cast iron baseboard for steam it works but usually always like crap and over time you will replace more air vents ona baseboard convector of any type in comparison to a free standing radiator . Talk of converting to another type of system like hot air is usually after all said and done never comes close to the heat a properly installed steam system deliveries and comfort plus generally a hot air system will always cost more to operate then a properly installed and operation steam system plus less moving parts and less air movement and nothing can delivery as many Btu for the given space required . As I tell customers if you want a hands off system then steam is not for you ,if you do not want to check your water level and want everything automatic then steam is not for you if you want a automatic feeder then you at a mim you be will notified by said automatic feeder when it time to replace your boiler cause it will be flashing which means ureuka I need a new boiler because I’ve taken on 1500 gallons of water in year cheerio to auto feeders lol . Steam system require at a mim a person to first off properly clean the boiler and to cycle the boiler for a complete heating cycle then while durning and after the thermostat is satisfied walk the basement and check all piping and main vent then proceed to get every supply valve and radiator vents for no n functioning vents and lanky supply valve, yeah it takes time and you pay but unless your there a few hours it’s half baked attempt . There a whole bunch of other things that should happen upon a maintaince visit like pull the sight glass **** ,low water cut off probe ,pull burners and clean chk for any roll out flame impingement and flood block and check for leaks ,flush and wand and fast skim ,flush wet returns this is a quick list and this is never done by most on a yearly maintenance visit for a few hundred it’s a 1/2 day mim for a complete real maintance other wise it’s a flash in a pan and if its 199 .00 job your just paying for some one to go threw the motions. Real maintaince is not cheap or fast and usually difficult to get correctly done when price and getting an bargain is top priority . Take non of this as a insult it’s just the truth by some one who does this work to eat so believe what you want pay who you wish but don’t be angry by what you receive and ps anyone who shows up to ur home wearing sneakers to work should be kindly shown the door there just sneaker wearing tool bags real men don’t wear sneakers to work they wear work boots steel tips and are usually not choir boys if your looking for that ina steam mech good luck that train does not exists for real knuckle dragging pipe spinning steam guys and usually completely political incorrect lol throw backs . That’s that’s
I know this to be a noble truth because it deal w it all the time . lol
The sweeten of a cheaper price is often forgotten after the bitterness of poor quality
Peace and good luck clammy

clammy

A quick ps real pros don’t use cheap o maid o mist air vents but real home owner and contractors who see no difference in quality and offer the cheapest so they can obtain the highest profit from mark up always use the cheapest of vents and materials because they see no difference and usually are not coming back .As it’s said ask the clam he does not care about feelings or offending he does not self promote just tells the truth as it is . Something most are afraid to do but it ,s really quite easy and some thing to live by that is telling the truth and that includes a I don’t know answer also . It never changes cause it’s the truth
Peace and good luck clammy

ethicalpaul

Don’t be mean clammy, we’re friends! You told me to call Henry’s and I did.

my house had no insulation, I lived with it daily. Then I added it and lived with it daily.

the difference is that less heat was released to the basement.

let me ask this: if lack of insulation causes banging then why doesn’t every insulated main bang after cold startup? That condition (cold, insulated pipes) is the same as uninsulated pipes until the pipes get hot.

HH says that pipes are miserable radiators because they have low EDR (true) and then HH says also that uninsulated pipes will cause banging and balance problems. It doesn’t make sense. Sorry! Still friends?

BobC

i suggested the adjustable MOM vent because it's the easiest way to figure out how to achieve a balanced system. Once you know what orifice goes where you can replace any failed MOM's with Gorton's. It will cost about 30% more but it's the fastest way to balance a system for a home owner if they don't KNOW what vest should go where.

Bob

Jamie Hall

A comment on the vents. Not on the make, but... if your boiler really was operating up to 5 psi, they are all toast. If they work at all, they will be erratic. You will need to replace all of them once you get the boiler pressure under control.

EBEBRATT-Ed

Baseboard can work on steam if the baseboards are on the short side. If they are long hook them up two pipe which is a PITA

ethicalpaul

I’ve taken apart gorton and MoM vents and Gordo has taken apart a lot more. I can’t see anything in there that would be harmed by 5 or even 10 psi.

is this just something we say, or is it real? How does a vent get hurt by 5psi?

Jamie Hall

If the vent is closed, the seat or valve itself can be distorted. You wouldn't think so, but the contact area is very small. Not saying it always does, but it can happen. When it does, though, the vent may be erratic -- it may not seal completely, or it may stick closed.

lovinglife

Waher said:

Boiler shouldn’t be operating above 2psi.

cut in of 0.5 to cut out of 1.5 psi is what the boiler should be set to in order to avoid problems. 

Radiator vents do not last long above 2psi. 

If the system won’t heat unless the pressure is set over 2psi, then there are other problems which need to be addressed immediately.

Thanks for the feedback. I'll mention this to the plumber who is coming today.

lovinglife

BobC said:

A "C" vent is a fast vent and that type of convector is usually happiest with lower vent rates because of all the condensate the convector produces. Are the other convectors venting at that same rate?
You can get vent kits that come with a vent and 5 different vent orifices for that single vent, this lets you dial in the correct venting rate.
Generally you want to vent the mains slowly and the radiators slowly. Keep in mind this is a heating system and it has to be balanced so it comes up to heat at about the same time.

Bob

I need to do more research on convectors to better understand you feedback

lovinglife

clammy said:

A quick ps real pros don’t use cheap o maid o mist air vents but real home owner and contractors who see no difference in quality and offer the cheapest so they can obtain the highest profit from mark up always use the cheapest of vents and materials because they see no difference and usually are not coming back .As it’s said ask the clam he does not care about feelings or offending he does not self promote just tells the truth as it is . Something most are afraid to do but it ,s really quite easy and some thing to live by that is telling the truth and that includes a I don’t know answer also . It never changes cause it’s the truth
Peace and good luck clammy

The maid-o-mist vent was the only vent available at the local hardware store on a Saturday to stop the leak until I could get a plumber to come out.

lovinglife

ethicalpaul said:

Don’t be mean clammy, we’re friends! You told me to call Henry’s and I did.

my house had no insulation, I lived with it daily. Then I added it and lived with it daily.

the difference is that less heat was released to the basement.

let me ask this: if lack of insulation causes banging then why doesn’t every insulated main bang after cold startup? That condition (cold, insulated pipes) is the same as uninsulated pipes until the pipes get hot.

HH says that pipes are miserable radiators because they have low EDR (true) and then HH says also that uninsulated pipes will cause banging and balance problems. It doesn’t make sense. Sorry! Still friends?

Less heat in the basement sounds like a positive result

lovinglife

BobC said:

i suggested the adjustable MOM vent because it's the easiest way to figure out how to achieve a balanced system. Once you know what orifice goes where you can replace any failed MOM's with Gorton's. It will cost about 30% more but it's the fastest way to balance a system for a home owner if they don't KNOW what vest should go where.

Bob

Thanks for the feedback. Is this an example of an adjustable MOM? This was the type of vents that one plumber told me were wrong



Is this vent that leaked a Gorton? That was the type of vent the plumber used to replace the adjustable vents.

lovinglife

clammy said:

Steam heat w baseboard convector is a slippy slope as it really isn’t the best choice and usually there’s always some splitting at some point in time . As for other suggestion that insulation doesn’t matter well after close to 40 years doing this I tend to completely disagree but then I do this for a living so by all means listen to another home owner who does not do this for a living Diy ? If you want the truth then look for some one who is versed in steam heating this may or may not be a plumber . Baseboard convector are not the ideal convector for steam a free standing radiator will operate far better . Personally I don’t even entertain the talk of installing copper ,steel or cast iron baseboard for steam it works but usually always like crap and over time you will replace more air vents ona baseboard convector of any type in comparison to a free standing radiator . Talk of converting to another type of system like hot air is usually after all said and done never comes close to the heat a properly installed steam system deliveries and comfort plus generally a hot air system will always cost more to operate then a properly installed and operation steam system plus less moving parts and less air movement and nothing can delivery as many Btu for the given space required . As I tell customers if you want a hands off system then steam is not for you ,if you do not want to check your water level and want everything automatic then steam is not for you if you want a automatic feeder then you at a mim you be will notified by said automatic feeder when it time to replace your boiler cause it will be flashing which means ureuka I need a new boiler because I’ve taken on 1500 gallons of water in year cheerio to auto feeders lol . Steam system require at a mim a person to first off properly clean the boiler and to cycle the boiler for a complete heating cycle then while durning and after the thermostat is satisfied walk the basement and check all piping and main vent then proceed to get every supply valve and radiator vents for no n functioning vents and lanky supply valve, yeah it takes time and you pay but unless your there a few hours it’s half baked attempt . There a whole bunch of other things that should happen upon a maintaince visit like pull the sight glass **** ,low water cut off probe ,pull burners and clean chk for any roll out flame impingement and flood block and check for leaks ,flush and wand and fast skim ,flush wet returns this is a quick list and this is never done by most on a yearly maintenance visit for a few hundred it’s a 1/2 day mim for a complete real maintance other wise it’s a flash in a pan and if its 199 .00 job your just paying for some one to go threw the motions. Real maintaince is not cheap or fast and usually difficult to get correctly done when price and getting an bargain is top priority . Take non of this as a insult it’s just the truth by some one who does this work to eat so believe what you want pay who you wish but don’t be angry by what you receive and ps anyone who shows up to ur home wearing sneakers to work should be kindly shown the door there just sneaker wearing tool bags real men don’t wear sneakers to work they wear work boots steel tips and are usually not choir boys if your looking for that ina steam mech good luck that train does not exists for real knuckle dragging pipe spinning steam guys and usually completely political incorrect lol throw backs . That’s that’s
I know this to be a noble truth because it deal w it all the time . lol
The sweeten of a cheaper price is often forgotten after the bitterness of poor quality
Peace and good luck clammy

Thanks for the feedback. So you agree I should replace the baseboard with a freestanding?

lovinglife

Jamie Hall said:

A comment on the vents. Not on the make, but... if your boiler really was operating up to 5 psi, they are all toast. If they work at all, they will be erratic. You will need to replace all of them once you get the boiler pressure under control.

Thanks. I'll discuss this with the plumber

lovinglife

EBEBRATT-Ed said:

Baseboard can work on steam if the baseboards are on the short side. If they are long hook them up two pipe which is a PITA

Thanks for the feedback. That would explain why I haven't had issues with the baseboard in the bathroom which is at least 50% shorter than my other baseboard raditors

lovinglife

The plumber said that my boiler needs to be cleaned because the dirty water is not properly turning into steam and instead backflows through the equalizer (which can cause banging).

The water level in the sight glass is very low when the boiler is cool and rises when the boiler is heating.

The boiler is over-due for a cleaning anyway, so I authorized that for Wednesday.

He also said the air vent on the baseboard raditor is too large and the air rushing back too fast could be the cause of the banging in that radiator. He will size the proper vent once the boiler is cleaned.

I have two main header pipes coming out of the boiler, one for the front of the house and one for the back. The one for the back of the house took much longer to heat up. That is also where the loudest banging noises usually occurs.

As far as we could tell, the back header pipe only feeds one 1st floor baseboard raditor and one 2nd floor freestanding radiator. He discovered that the air vent on the second floor radiator was broken. That radiator eventually heated up and did not leak water or steam even though the air vent was broken.

Of course, there was no banging noises while the plumbers were here. The heat was turned off for 8 hours waiting for the plumber to arrive 6 hours late. I assume all of the water had a chance to flow back by then so there were no water/steam collisions.

But then again, one would think that the pipes that has cooled down to 66 degrees would have caused some banging, correct?

The pressure also didn't rise above 2.5 psi while the plumbers where here.

We'll see what happens after the boiler is cleaned and those two radiators have the proper air vents.

Thanks again for all the feedback.

ethicalpaul

lovinglife said:

Less heat in the basement sounds like a positive result

It is if you actually want less heat in the basement. But insulation won't affect banging or balance or anything else.

That vent you showed is not a Maid O Mist. A real Maid O Mist (not an imitation) is a fine vent.

Waher

Insulating pipes can reduce banging and help with slow distribution if a system is plagued with premature condensate in a barely sufficiently pitched pipe somewhere. If steam has to spend time warming pipes and fighting condensate then insulation will help. It is not usually the underlying problem though.