1920's Air Over Water Boiler System: Constant Air Bleeding
Hello all,
It's been a while since my initial posts. For insight into the system I'm (homeowner) dealing with, see here.
The system has been working well enough and kept us quite warm the past two winters. This fall, we noticed that one of the radiators in an upstairs bedroom must have been leaking water as the hardwood floor beneath it has water damage and the ceiling (plaster) on the floor directly below has a crack with rust coloring to it.
We called out 2 Heating/Plumber contractor to take a look. Should be noted that in our area (southwest Missouri), only the old timers will work on our system and "work on" is a loose term. No one want to touch it... literally no one will touch the main boiler system due to insurance concerns.
One said that a length of pipe needs replacing for $1250.
The other (my preference) pointed out that it was more likely the packing valve that leaked and caused the rusting on the pipe and floor. He tightened the packing valve and told me to let him know if it leaked when the boiler was filled, fired, and pressurized.
I finally got around to doing that when it was cold enough to not turn the house into a sauna and there appears to be no leaking. That said…
This radiator is one of the furthest from the boiler. It's large. It's a bit rusted on the underside where some of the paint is gone (see photos). I fired the boiler, brought it up to temp (160ºF) added water (water from the hot water heater's spigot to the boiler via a drain spigot on the rear of the boiler. This is necessary as the main water line into the boiler has, for an unknown reason, 2 gate valves, both of which are frozen shut) and bled the system (via radiator bleed valves throughout the house) to 13.5psi @ 160ºF.
A few nights later, we needed heat again so I fired the boiler. I have a security/nanny camera pointed at the temp/pressure gauge and noticed the pressure was up to 20psi (pressure release valve is 30psi). I rushed up to the bedroom to the radiator in question and bled the system. Pressure dropped back down to about 12. I did not add more water.
Now, on every subsequent firing, I proactively bleed that radiator.
Thanks to everyone here, I know what I know about this system and how it works, but don't want to make assumptions nor pay another service call fee to conflicting contractors.
My assumption would be that there is a crack somewhere that's letting air into the system. If this sounds plausible, any hope in finding where and solving it?
If not, is it possible to install an automatic bleeder valve?
Thanks as always!
PS - I have not (shame on me) flushed the expansion tank as it was suggested to do in my first posting linked above.
Comments
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Air problems can be many and varied. In a closed system, there should no need to vent air on a regular basis. If you are finding air in that particular radiator regularlym then that air may be coming from a leaking pump of packing nut. but more information is needed. I'll read your previous post and get back to you with nay questions.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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Your overpressure is due to a waterlogged tank. Absent an Airtrol setup, draining the compression tank is part of annual service before the start of the season.
There should be a valve between the tank and the system. Close that, drain the tank,close tank drain ,open the tank to system valve and refill to 12ish psi.
BTW,if you dont take care of that,you'll be looking at fixing more valve packing.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.0 -
So, you're always getting air at just the one radiator? You say it's the furthest one, 2nd floor?
A picture of the rusty underside of the rad may be helpful.
Also, it's not clear whether your system is still gravity or if there are other pumps besides the Grundfos for the bathroom.
Lastly, please show how your compression tank is hooked to the system. I have suspicions about what was attached previously where your bathroom line is attached now.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.1 -
Duly noted. Thank you!
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Appreciate your insight as always.
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I’ll reply at length tomorrow and with photos. Thanks!
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Am I the only one concerned about that badly corroded pipe connected to the radiator (last couple pictures)? 😳
I’m surprised it’s not continuously leaking.
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You are in fact not the only one. I'm quite concerned about it and whether or not it's causing the current issue, it feels / looks like it should be something that should be replaced (considering the system is kept in use).
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Some steel wool or a wire brush and some Rustoleum paint will fix that pipe. As long as the pipe above it has been fixed and no more water leaks on it, then you are good to go. If that wire brush causes the pipe to leak then replace it. Better to know when it happens than to wait for it to happen when no one is looking. Don't ya think?
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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Piling all my replies to comments into one. Replying in particular to @delcrossv & @EdTheHeaterMan . Thanks to everyone for their help, it's much appreciated.
The system is gravity fed, however, whomever redid the bathroom and moved the radiator and replumbed it added a pump. When I first posted about the system someone mentioned the pump's installed orientation was incorrect.
There should be a valve between the tank and the system. Close that, drain the tank,close tank drain ,open the tank to system valve and refill to 12ish psi.
There's no valve that I can see between the tank and the system. How should I proceed to drain the tank? My assumption is with the system cold and pressure low, simply open the spigot, drain it, close the spigot?
So, you're always getting air at just the one radiator? You say it's the furthest one, 2nd floor?
The radiator in question always has air in it. 2 of the other radiators on the second floor will also have air but only about 10% as much as the radiator in quetion.
A picture of the rusty underside of the rad may be helpful.
Also, it's not clear whether your system is still gravity or if there are other pumps besides the Grundfos for the bathroom.
Lastly, please show how your compression tank is hooked to the system. I have suspicions about what was attached previously where your bathroom line is attached now. So, you're always getting air at just the one radiator? You say it's the furthest one, 2nd floor?
A picture of the rusty underside of the rad may be helpful.
Also, it's not clear whether your system is still gravity or if there are other pumps besides the Grundfos for the bathroom.
Lastly, please show how your compression tank is hooked to the system. I have suspicions about what was attached previously where your bathroom line is attached now. See photos:
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This is the easies way to drain your expansion tank. (that is what we call it in the trade).
You are actually filling your expansion tank with AIR.
- First step is to put a garden hose on valve A.
- Place the other end into a floor drain, or a laundry tub or drain pipe, or outside. just as long as the end of the hose is at least 2 feet below the basement ceiling.
- Open valve A and let the boiler pressure drop until no more water flows out the end of the hose.
- Slowly crack valve B open and listed for the air to gurgle in to the tank.
- Let the air into the tank until the tank is empty of water and full of air.
- You can check this by listening to the air bubbles they will change frequency as the water in the tank gets lower and lower.
- You can listen to hear if any bubbles start to go into the main pipes. You dont want too much of that to happen
- You can rock the tank in the ceiling and see how heavy/light it feels.
- When the tank is empty Close Valve A and B.
- Fill the system with water until you get 12 PSI
- The expansion tank will be 1/3 air and 2/3 water. Ready to operate.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
2 - First step is to put a garden hose on valve A.
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Many, many thanks. Simple thing for you to explain, I’m sure, but incredibly helpful for me.
To clarify, step 7… I’m to fill the (cold) system with water so that the pressure gauge reads 12psi, correct?Testing my assumptions / giving myself a quiz… I’m currently set to an operating temp of 160°F. When that temp is reached, will the system pressure remain at 12psi now that the expansion tank has been properly drained?
One more thing… the gate valves that connect the system to the home’s water main are stuck closed. The only place I have to refill the system is Valve A (in your diagram). Will this be an issue?
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Ok, thanks for the pics. You may be able to just open the drain if you first make sure all the rads are free of air. No guarantees though. It's a larger version of the soda straw trick. If that fails, you'll have to refill the system above the level of the tank connection and purge the rads.
With that convenient union, you could drain the system, open the union and put in a valve for easy draining. You may want to wait untl spring for that. Good time to replace your fill valves and add a pressure regulating valve too.
Your rad looks leak free, so as @EdTheHeaterMan says, a little steel wool and some paint.
If it were me, I'd ditch the pump and splice in a piece of pipe.
Regarding the boiler, I'd vacuum the firebox and burner, it looks like someone already put in baffles.
A pilot safety can be put in line in spring as well as a barometric damper. Maybe if you installed the damper, your service guy can set it as part of service rather than an "upgrade".
This Baso should work for you.
https://www.supplyhouse.com/Baso-Gas-Products-L62GB-1-Safety-Shutoff-Device-100-Lockout
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.1 -
@Globalksp said: "Testing my assumptions / giving myself a quiz… I’m currently set to an operating temp of 160°F. When that temp is reached, will the system pressure remain at 12psi now that the expansion tank has been properly drained?
(Before)The temperature from cold 60° rise to 160° will cause the water to expand. Based on that expansion tank being more than 2/3 full of water, there is not enough air cushion for the water to expand so the pressure goes up.
(After) When you have more air in the tank, then there is more room for the water to expand. That way the pressure will go up much less. But it will always go up a little in a closed system. It has toT There is no where else for the expanded water to go… so it goes into the expansion tank and compresses that air a little. More air to compress = less pressure rise.
And: One more thing… the gate valves that connect the system to the home’s water main are stuck closed. The only place I have to refill the system is Valve A (in your diagram). Will this be an issue?
Not at all, just use the water heater drain to get the pressure back up to 12 to start with. Think about how clean the bottom of that water heater must be!
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
1 -
@delcrossv said: If it were me, I'd ditch the pump and splice in a piece of pipe.
I would wait on that too. your piping to the bathroom radiator may not be "Gravity Heat Friendly". That may be why there is a pump on it. and that little loop is not going to effect the gravity system from operating the way it should. If your bathroom gets too hot, you can put a thermostat in there and make the pump stop circulation once the bathroom reaches temperature.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
1 -
Fair enough. If the bathroom rad gets hot with the pump off, you probably won't need it.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.1 -
Thanks again to you both.
@EdTheHeaterMan ”
Think about how clean the bottom of that water heater must be!”
Considering the hot water heater is 13 years old and is fed by 109 year old galvanized pipe, I almost don’t want to think about it! Should I think about it before using it to fill the system??0 -
Nah. Should be fine. Blow out a couple of gallons into the drain first if it worries you.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.1 -
do either of you have any thoughts on why there would be two gate valves installed on the water fill line coming from the home’s Water main?
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Yes. The original one was leaking past and the boiler pressure was going too high, then the second one was installed to close off the water but they never removed the original one that is leaking. That might involve turning off ALL the water in the house to do it right. It was just easier to add a valve.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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Like so many things that were done to this home before we owned it , the easy / cheap way was always taken 🫠
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@delcrossv
thanks!1 -
Edit. See Ed's post above. I'd pull them both and install one high quality ball valve : Watts or Apollo. Is there a PRV anywhere on the feed line?
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.0 -
there isn’t a PRV anywhere on the feed line.
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Re: You can listen to hear if any bubbles start to go into the main pipes. You dont want too much of that to happen…
And what if it does? I emptied the expansion tank. At some point close to or after the tank was empty, I began hearing bubbles throughout the system’s main pipes. The bubbles have been gurgling for about 10 full minutes now and are starting to abate.
I assume I left the expansion tank valve open too long, mistaking the bubbles I was hearing as expansion tank bubbles.
Does this change the rest of the process in any way?
Thanks as always0 -
Also, everyone was correct, the expansion tank was VERY full.
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could this be a PRV? Also a correction, the valve with the red handle is operable. However, the valve below it appears to be stuck closed.
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That Red circle is a standard union. Used to put threaded pipe together because you can turn the last connecting pipe in one fitting and the other fitting at the same time without the fitting(s) leaking
The Black handle valve is the original valve. The Red handle valve is the newer valve (still very old). I would try to turn the Black handle valve with a pair of offset pliers (sometimes called Channelock™). If the valve is really stuck the handle will break before you damage the water seal. If that happens then you will need to replace the valve anyway. IF you get it to open then leave it open and remove the handle. That way no one will ever try to close it.
The reason the valve is stuck, is because someone wanted to stop the valve from passing water and used pliers to close it. Now you need pliers to open it.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
1 -
It's a compression tank.
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No worries, start filling the system and bleed the radiators. Best with two people with phones: one on the fill line to start and stop the flow, and one going rad to rad getting the air out.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.1 -
Old valve (bottom) looks like it has elvish script on the bonnet. "One Valve To Rule them All…"
How old is that system anyway? 😲
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.1 -
I managed to get the original, black handled valve to operate. It was open all along. It is open now. However, when I open the valve above it, no water flows into the boiler. This leaves me confused. I followed the line back to the main and there’s no other valves.
For what it’s worth, I enjoy learning about all of this I haven’t know for 42 years!
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Let’s see if I can convince the wife to do this lol.
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What’s the purpose of this little bleed cable that’s attached to the original valve?
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Back in the day, we used 2 people to vent the radiators. no cell phone needed. You bang on the radiator pipe 2 times if the air stops coming before the water fills the radiator. That lets the person in the basement know to open the valve to let more water in. Three times means that all the radiator are full of water so the basement person can stop adding water.
I think if you bang three times on the ceiling, you might get lucky tonight. 🎶 But that may be a different song. 🎵
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
2 -
Plug to drain water from the valve (and above) so it doesn't freeze in there.
Old pipe might be plugged with crud too if you get no flow with both open.
Close both for now and use the water heater method.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.0 -
company inscription. “TRIUMPH (I think)” Brass Co. Columbia, SC
And the home was built in 1915. Unsure exact date of boiler but assuming similar time frame. The post I linked to in my first post in this thread has history details.1 -
Cool- just having fun with the Lord of the Rings reference. I think @EdTheHeaterMan is having a bad influence on me. 🤣
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.3 -
and is quite common.
1 -
I’d like to give another thank you to everyone who helped out. The system is up and running extremely well, sitting at 12psi when cold and creeping up to just about 13psi @ 160°F. 🙏🏻
3
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