One Baseboard Radiator Not Heating


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Old 10-13-07, 10:25 PM
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One Baseboard Radiator Not Heating

Some back story. My family recently purchased an old 1916 Georgian Colonial for my brother, myself, and a couple of roommates to live in during college (interestingly enough, its a heck of a lot cheaper to buy a house and make monthly payments on it than it is to pay for room and board, and in the end, we can sell the house!).

At any rate, one big point of contention was the fact that it had a boiler. The house was vacant for about a year before we purchased it, so we had the boiler tested prior to purchasing. I did some reading around this forum tonight but didn't seem to find a way to diagnose and treat to the specific issue we're experiencing.

After we bought the house, we had a boiler guy out and he did some checks, fixed a clutch on one of the pumps, and replaced the relay and thermostat. All seemed well - but that was August, we didn't need heat. It is now October, and things seemed to be going well. There were some hiccups in establishing heat upstairs, but after bleeding some of the valves on either end of the baseboard heating, I got three of the rooms with hot water flowing through them.

But then there is my room. When it was spitting water, it was always cold. Now, after the other rooms are working properly, my room goes in stages. With the pump running, I hear air initially, however instead of pushing out, it seems to be sucking air in (I put a tissue near the little vent hole, and it didn't get blown around like it would have if the vent was expelling air). Then, I get either a little bit of dribbly water, or nothing. Before bleeding the other bedrooms - I'd get cold water streaming out, cups at a time.

In an attempt to put information out there, I'll try my best to explain what we're working with. It is a natural gas fired boiler. There are two zones - one feeds a fan/radiator combo in the basement, and the other one services the first and second floors. I have gone through and bled all of the valves I can find at the baseboard heaters. There are 1.25" supply lines running throughout the basement (and presumably the walls, though I'm not sure). Each baseboard heater is serviced from this main line via two Ts, one being a special T (check valve?). Its old, there's no doubt about that, and the baseboard heaters aren't original - replaced from traditional upright radiators who knows when.

If anyone could give me some tips, tricks, or things to check out and investigate, I'd greatly appreciate it, because this is Michigan, and its getting mighty cold at night.

Thanks in advance for any advice you can offer!

Steve
 
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Old 10-13-07, 10:33 PM
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Sounds like you need more water pressure overall and to bleed out the air in that branch from a bleeder by the rad.
 
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Old 10-13-07, 10:58 PM
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Originally Posted by Who
Sounds like you need more water pressure overall and to bleed out the air in that branch from a bleeder by the rad.
Wow, I did not expect a response so quickly. I literally just bled the valves in my bedroom, and just now it forcably shot air out, like it did in all of the other rooms. While bleeding it (and this has happened a couple times before) I could hear water gurgling (sounded like what would sound if you flipped a glass bottle filled with water upside down. Gurgling as air gets into the bottle, if that makes a difference). But, once the air was out of the line, I only got a little dribble.

After that I decided to check the other rooms. One room would sputter air, then water for about a minute. Back and forth, and then just a dribble. After it stopped, I tried my brothers room and it was pulling air in - which my room now is doing again as well.

How can I increase the pressure on the system? There is an inline regulator, but it doesn't appear to have the ability to adjust it. There is a tag on it that says "Set to 12 lbs" which is about what the boiler is reading as well.

Also, what would I be looking for to accomplish bleeding the air in the branch. From what I can see, the only place on the boiler I can "bleed" would be the expansion tank and the pressure release valve. Then again, I'm not 100% certain what I'm looking at.
 
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Old 10-13-07, 11:16 PM
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How much elevation between the boiler, and the highest piping in the system ? You need about a half pound of pressure for every foot, plus 4-5 pounds.

example: Boiler in basement, 3 story house. The highest point in the system may be something like 24' above the boiler. Half pound per foot is 12 PSI, PLUS 5 = 17 PSI.

That 12 PSI is for 'average' installations, and could be marginal for an older home with high ceilings.

Those 'special' tees are probably Monoflo types. They have a venturi inside that creates a pressure differential that forces the water through the heating loops. (you _are_ at an engineering school, right ? )

Who is probly right again, not enough pressure.

Can you post some pics on photobucket and a link to them here ? Let's see the regulator and the expansion tank at minimum.
 
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Old 10-13-07, 11:32 PM
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Pictures coming right up. And I lied. The valve looked like it was non adjustable because there was a cap on top of the screw. Also, when looking at it while the pump is running - its closer to 9psi. From the reading I've done (there's a lot of reading to do) it seems like you need to set the pressure while cold. Does cold refer to not running, or off? I guess I never really paid attention when it was running.

Its a two story house, probably about 20' from the boiler in the basement to the highest radiator.


This is the whole shebang. The pump that is visible in this photo is the one that services the first two floors of the house. The other identical pump services the fan assisted heater seen to the right.


The expansion tank.


And, the valve.
 
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Old 10-13-07, 11:42 PM
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Originally Posted by NJ Trooper
Those 'special' tees are probably Monoflo types. They have a venturi inside that creates a pressure differential that forces the water through the heating loops. (you _are_ at an engineering school, right ? )
I missed this part of your post in the reply.

Yep! In fact, up until recently I was going for my Computer Engineering Degree. Switched to Business and IT but I am familiar with the venturi effect from my fish keeping
 
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Old 10-14-07, 07:42 AM
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Originally Posted by tekknoschtev
I missed this part of your post in the reply.

Yep! In fact, up until recently I was going for my Computer Engineering Degree. Switched to Business and IT but I am familiar with the venturi effect from my fish keeping
The fast-fill may be on its way out?
 
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Old 10-14-07, 08:21 AM
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Fast Fill?

That reducing valve has no Fast Fill feature.
Make sure orange valve (photo 3) is open.
Remove the cap on the reducing valve, loosen the lock nut, turn the screw in about 1 full turn.
Do you hear water being fed?
Check pressure gauge on boiler. Don't exceed 20 psig cold.
 
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Old 10-14-07, 09:00 AM
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Originally Posted by Grady
That reducing valve has no Fast Fill feature.
Make sure orange valve (photo 3) is open.
Remove the cap on the reducing valve, loosen the lock nut, turn the screw in about 1 full turn.
Do you hear water being fed?
Check pressure gauge on boiler. Don't exceed 20 psig cold.
The orange valve is part of a bypass from city pressure to the boiler and yes, it is open. The one that would allow city pressure to the boiler is closed.

I just attempted to the screw ~1 full turn and I saw no change on the boiler's pressure gauge (which, as of this morning was reading just over 8psi not running). I did not hear any additional water running. I grabbed my friend and had him watch and we loosened the screw more. From very wide open to all the way snuggly closed, no water rushing sound. The pressure didn't change. To make sure that the pressure gauge wasn't stuck, I slowly opened the city water valve, and the needle rose slowly. Turned that back off.

So, to me, it would indicate that the valve is bad. Is this something that Home Depot would carry? Or Lowes/Meynards? I'll actually probably check there before I'm back at the computer ti get a response

I'm crossing my fingers that its just this valve. Thank you for helping me in the detective work!
 
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Old 10-14-07, 10:00 AM
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Steve, in lieu of an immediate fix for the auto-feed regulator, if you've got another valve that feeds water into the boiler, you can manually add water while keeping an eye on the pressure gauge. Add water until you get to about 15 PSI, and close the valve. Go to the bleeders upstairs and let the air out, you should now have pressure in those pipes. As you let the air out, the pressure will of course drop again, so get one of yer buds on the cell phone in the basement and have him add water a little at a time as it drops. Don't let the pressure go over like 20 or so.

That's probly not gonna be a real easy job to replace that valve, hope you've got some big wrenches ! AND, unless there's ANOTHER valve on the other side of the regulator, you will probably have to drain the system.

That existing valve may have a screen in the bottom that you can remove and clean out. Also, that brass thing ahead of the regulator ... that's probably a check valve to prevent backflow into the domestic water, that could be messed up too.

Personally, in view of the fact that it's getting cold, and the system otherwise works, I might opt for keeping an eye on the pressure gauge and adding water manually as needed. (it really shouldn't be needed once it's full, as long as there are no leaks). I'd wait till spring to tackle that...

Whattaya think Grady ?

WAIT... I just looked at yer pics again ... I think there IS a valve on the outlet side of that regulator, that one needs to be open also... BUT you can close both of those valves to isolate the regulator, and you won't need to drain the system.
 
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Old 10-14-07, 10:13 AM
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Steve, when the boiler guy was out, do you know if he drained the expansion tank ?

When you get the pressure to where it belongs, and the system fired up, monitor the pressure gauge the first time you heat it all up. If that pressure starts to climb drastically it would indicate that the expansion may be water-logged.

I _think_ that red thing on the bottom of the expansion tank is supposed to prevent water-logging though...

it does appear that there may be a small leak at the pipe going into the expansion tank valve (green stuff on the pipe).
 
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Old 10-14-07, 10:18 AM
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Reducing valve

Originally Posted by NJ Trooper

Personally, in view of the fact that it's getting cold, and the system otherwise works, I might opt for keeping an eye on the pressure gauge and adding water manually as needed. (it really shouldn't be needed once it's full, as long as there are no leaks). I'd wait till spring to tackle that...

Whattaya think Grady ?

WAIT... I just looked at yer pics again ... I think there IS a valve on the outlet side of that regulator, that one needs to be open also... BUT you can close both of those valves to isolate the regulator, and you won't need to drain the system.
Grady thinks Trooper is right. Do what you have to do to get heat & tackle the reducing valve when you get a couple of warm days or wait until spring. The fact you have unions & valves on each side will make the job MUCH easier but by no means Murphy proof. It could still require the use of a torch to soften the pipe dope.
 
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Old 10-14-07, 11:37 AM
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Neat pressure calculator

How much pressure do I need ?

Pressure Calculator
 
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Old 10-14-07, 11:45 AM
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Well, promising news. I went out to Lowes, Meynards and Home Depot. Home Depot informed me that they just (as in within the last month) shipped the valves to New York because they'd had them here for years, and not many sold (for what its worth, this Home Depot is very lacking in the plumbing supply department, but its 20 minutes closer than the Meynards and Lowes). Lowes looked at me with a 'what?' face, and Meynards didn't carry them.

I followed the advice here however, to manually fill it, and viola, water is now coming out in my room. I purged the air, and am waiting for hot water to start coming my way. Thus far, its only been cold water, but the thermostat was only at 65, so it hadn't been running a lot.

But, the fact that now water shoots out instead of dribbling gives me a ray of hope. I'm looking forward to heat coming through the pipes! And, yes, there are gate valves and unions on each side of the valve, so replacement wouldn't be as difficult were there not valves and unions.

So, again I thank everyone for the great advice. It has potentially saved us some headaches and the cost of having the boiler guy out again.
 
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Old 10-14-07, 03:15 PM
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Well, good news bad news. I still have water flowing in my room, and no air, but no hot water. Everywhere else gets nice and toasty water running through the baseboard heaters, but not this room.

Any tips on diagnosing this situation?
 
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Old 10-14-07, 04:12 PM
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You probably still have air in that loop, even though you get water now when you open the bleeder. Monoflo's can sometimes be tricky to get all the air out. The air bubble is probably downstream of the bleeders. Did you say that there are bleeders on both ends of the b/b ? And you bleed both of them ?

Are there any valves on the _other_ heating loops ? Sometimes closing them down will force more water through the air-locked loop and get the bubble moving.

Other than that, keep bleeding the one in your room. Can you rig up a hose (tubing) to the bleeder ? If so, open it all the way and let it run into a bucket. Eventually that bubble will move and be expelled (hopefully).

You might try increasing the pressure some too, just be careful not to overpressurize it, cuz it will increase when it gets hot. Increasing the pressure will cause the air bubbles to be compressed and they may move. When you do get it flowing, return the pressure to the proper setting.
 
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Old 10-14-07, 04:38 PM
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Alright, I just wanted to make sure that continually bleeding it wouldn't cause problems other than dropped pressure. It makes sense to me that there would be air somewhere.

Yes, there are bleeders on each end of the baseboard heater and I've bled both. I'll keep at it. Logically, it makes sense that eventually hot water.

Thanks for the encouragement.
 
 

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