Why do I have to keep bleeding my radiator

Kevin Doll

We recently purchased an old 1930's home. It has a gas fired boilor that is 20+ years old (Mclein brand I think) It feeds 7 large radiators on the main floor - at one time it also fed 6 radiators up stairs. They have removed the upstairs bedroom radiators. Instead - they added an airhandler in the attic and put one radiator there. When the air handler kicks on - it blows a little bit of heat into each room - not ideal.

recently - one of my large (8' long) radiators in the sunroom has stopped working. I have had to bleed air off of it almost everyday. This doesn't seem correct to me. When we moved it we had about 13lbs of pressure in the system. Now we have about 10. I am not sure how to put more water in the system (if this is the problem) I see about 10 different valves.

any thoughts on why I am having to bleed this off? Any thoughts on how I can get more heat up stairs?

KCA_2

Well..


It may be a matter of how the system is circulated. Are there circulators? Or is the system a gravity feed?
Are other radiators on the same loop or is this one all by itself?
It may also be a matter of pressure however, I assume that the sunroom is on the main level and that the ones on the upper level are running fine. That being the case then pressure is probably OK. Yet for every 2.3' of elevation you need 1PSI of operating pressure (+3PSI). 10PSI seems a smige low. 10PSI would suggest that the upper level (fan coil in the attic?) is 20' above the boiler.

Let me know

:-) Kca

Kevin Doll

If by "circulator" you mean a pump - yes it has a pump. I think that other radiators are on seperate loops - because there is a second smaller one in the sunroom (main floor) also and it is running fine. The one in the attic is probably close to 20' - I have 9' ceilings. Knowing that I did have more pressure prior to wintor starting - what would have caused the loss? Looking at all of these valves - is there a book or something that would show me how to increase the pressure by adding more water to the system?

KCA_2

Could be the pump then!

Unless the other small radiator in the sunroom is on a separate one.
Or..
Maybe the kids turned down the radiator valve (temperature setting) Could be.. You might still get some flow.
Or..
How much air do you get when you bleed it. Just a little or a bunch?
How is the radiator controled? T-stat or Radiator valve?

:-) Kca

ta finnegan

Idea.

How about pumping away? Is the circulator on the supply or return side?

Changing this out could be critical.

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Kevin Doll

To KCA - the radiator is controlled by a T-Stat I belive. There appears to be a valve on each radiator - but they are all seized - can't turn any of them. It takes 4-5 mintues to bleed it - seems like a lot of air to me.
I will have to look at the pump this evening to determine if supply or return - is there an easy way to tell?

obviously this is all very new to me - sorry to keep asking so many simple questions.

KCA_2

What TA was talking about

is the pumping arangement on the "Primary" loop. Thats the piping right off of the boiler. If there are individual pumps (you would have a few to support a number of radiators) then that's a different matter.

Even still.. You shouldn't be getting that much air consistantly fron that radiator. Even if the pump is bad.
a little I would understand.

I'm guessing that the radiator in question is about 10' or so above the boiler. (no matter how far away)
If that's true then it wouldn't be a pressure problen except that (I know Taco pumps) have a minimum working pressure called Net Possitive head, of about 14PSI depending on flow rates.

Anyway.. There should be a water make-up line attached to the system. As long as the system is circulating (putting cold water into a firing empty boiler can be VERY dangerous) a valve should be in place to throttle the water into the system. Trace the domestic water lines around the boiler to find it.

It may be best to call a local heating contractor. Troubleshooting and filling can be something that takes experiance. Not to mention dangerous once you take your hands out of your pockets.
But you can e-mail me if you want.

:-) Kca

Dan Law

Air venting required

Kevin,

I read thru your posts. If I understand the first correctly, you have and air handler in the actic with a HW coil in it (the radiator you spoke of?). Also sounds as if you might have some dead ended vertical risers at the previous 2nd floor radiator locations. If this is the case, I ofer the following. Seems to me at some poin the system was drained (at least partialy)of water. This allowed air into the system. The vertical risers (if still present) could be acting as "air resevoirs" for lack of a better term. You bleed air from the first floor radiator and circulation improves slightly, but the air in the resevoirs" gets picked up and soon your air bound agin. You describe the heat from the attic air handler as a little. This air handler is the high point in your system - there sould be some type vent at the top of this heating coil or at least on the risers that feed it (probably a manual vent). This is where the air is best vented, as it tends to rise to the highest point. If in fact you have these dead ended vertical risers, venting them could be difficult. If you find this is the case, I recomend hireing a local pro to remove the unused risers from the mains.

Dan Law

Air venting required

Kevin,

I read through your posts. If I understand the first correctly, you have an air
handler in the attic with a HW coil in it (the radiator you spoke of?). Also sounds
as if you might have some dead ended vertical risers at the previous 2nd floor
radiator locations. If this is the case, I offer the following.

Seems to me at some point the system was drained (at least partially)of water.
This allowed air into the system. The vertical risers (if still present) could be
acting as "air reservoirs" for lack of a better term. You bleed air from the first floor
radiator and circulation improves slightly, but the air in the reservoirs" gets picked
up and soon your air bound again. If in fact you have dead ended vertical risers,
venting them could be difficult. If you find this is the case, I recommend hiring a
local pro to remove the unused risers from the mains.

You describe the heat from the attic air handler as “a little”. This air handler is the
high point in your system - there should be some type vent at the top of this
heating coil or at least on the risers that feed it (probably a manual vent). This is
where the air is best vented, as it tends to rise to the highest point.

I agree with KCA - 10lb seems a bit low as you describe your home with the high
ceilings. There is a automatic feed valve on you system that is normally set from
the factory @ 12lbs (your gauge may be off a bit and this is what your reading -
factory feed pressure) If you locate the attic vent, but when you open it, you get
no venting action, this would indicate too low a pressure in the system to lift the
water to the height required in the attic.

You’ll need to be the judge of when it’s time to call in a pro, but I think that time is
near. I mean no offense by this, but as KCA says, venting and filling can get
difficult. My advice on locating the best service company in your area is to phone
a local heating supply house. These houses will not sell to you (or shouldn’t) for
liability reasons, but the owners or counter guys are in an excellent position to
know who’s who in the area - they know em all. I’m sure they’d be happy to give
you an informed referral.

Best of luck,

- temptrol

ta finnegan

another thought.

I guess I'd like to know what the total friction losses are for the piping. Figure that out. What kind of circulator is on the piping, and where the circulator is. Furthermore, is the piping matched to the flow rate?

What if friction losses allow the suction side of the circulator to pull a vacuum, air would pull in from anyplace available.



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Thom Masse (a rookie)_2

I gain knowledge just be reading...

Thanks guys, just reading of other problems gives me the thought and understanding of what I may some day encounter. And I hope I will be the one to solve the "issue". ( we do not have problems we have issues.)

KCA_2

Challenges!


Just Challenges!

:-) Kca