Can't bleed baseboard radiators. Drain & refill system?

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Old 12-16-13, 11:47 AM
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Can't bleed baseboard radiators. Drain & refill system?

I am trying to help my son with his baseboard heating system. They have had the house 4 years and last year a zone has stopped heating. We were told it was probably air in that zone. I spent the day trying to help bleed the system yesterday but there are no valves on the return pipes. I read someplace that this might be the case if the house was converted from standalone radiators to baseboard but we don't know if that is the case. I've attached a few photos that show the plumbing.

There has been a pump added for the basement zone and it does have a valve to bleed (which we did). They had contacted a service but were told they would probably have to drain the entire system. I'm puzzled because if they drain the system and start to refill there still needs to be some way to allow the air to escape as it is filled or am I missing something?

The other odd thing is that while they can close the return on two of the zones there is a third zone that doesn't even have a shutoff on it.

Your expert insight would be much appreciated.

BTW, I've looked at many threads here (which are very useful) and other places and believe I have a pretty good working knowledge of the system basics.
 
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Old 12-16-13, 11:59 AM
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The automatic air eliminator looks to be damaged. Should be replaced.

Which of the three zones has no heat?

Draining and refilling the system won't help and will inject even more air than you have now.

What is the system pressure? Temporarily jack it up to about 25-28 psi, hot, which might help bleed the trapped air.
 
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Old 12-16-13, 12:16 PM
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Thanks for your quick response. It is the living room zone that stays cold. You know, I hadn't noticed the "automatic air eliminator" until I was uploading the photos and wondered if that is what that device was. The pressure seemed good, ~16psi according to the gauge. It would drop as I was bleeding the basement zone but we watched that it didn't drop below 10. I believe the pressure valve was rated at 35psi (if I remember correctly).
 
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Old 12-16-13, 12:27 PM
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The basement zone has a "purge" valve on it, the one with the hose attached. The in-line valves on the other returns are for balancing the system. All the baseboard convectors should have air vents on the return side. You DO have to remove the end covers at the very least in order to access these vent valves.

Some pictures of the baseboard convectors would help.
 
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Old 12-16-13, 04:14 PM
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They had contacted a service but were told they would probably have to drain the entire system. I'm puzzled because if they drain the system and start to refill there still needs to be some way to allow the air to escape as it is filled or am I missing something?
I wouldn't call them back. That response indicates ignorance.

The text in the last pic is too small to read. What IS that crusty thing?

In the pic with the air scoop and the air vent... does that pipe coming off the bottom go to a large steel expansion tank above the boiler?

Does it appear when looking closely at the air scoop that the tapping that the air vent is screwed into is 'bushed down' to a smaller size? If so, can you determine what size pipe thread the original tapping size is?
 
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Old 12-16-13, 06:21 PM
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NJ, sorry 'bout the text. That is a good question. When the main hot water line goes up to the floor joist and start their run it splits into two runs. One we suspect goes to the 2nd floor and the other to the 1st level with the living room and dining room. They must split again to feed those two rooms separately since they each have their own return and the living room is not flowing. Shortly after the main splits into the two runs these devices are in the lines. We have no idea what they are but were afraid to try and turn them or mess with them since they were so rusted. I wonder if they might be valves to close either of the two hot water feeds.

You are correct, the pipe coming out of the bottom of the air scoop does go up to an expansion tank.

My son is taking some additional photos of the scoop to try and answer your other question. Unfortunately he lives about 2 hours away from me.

I'm puzzled why they wouldn't have put valves above the zone shutoffs to allow you to bleed them. Also, the 2nd level zone doesn't even have a shutoff so you can never isolate that zone to force the other two to flow (unless those crusty things are valves and would allow that). Whoever put in the basement zone seemed to know it needed a bleeding valve because it seems to be configured like I've seen explained elsewhere.

I'll post the photos as soon as my son sends them to me. I just skyped him.

Thanks for engaging and trying to assist!!
 
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Old 12-16-13, 08:15 PM
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Ok "Furd", I was under the assumption that this was a closed system from what I had read elsewhere. I'm sure we checked for "bleeders" when we first looked at this several months ago. I just talked to my son and he went back to check both ends of the radiator and FOUND the "bleeders". He worked on the ones in the living room and now has some warm water circulating through the system. He said there seems to be a LOT of air in that zone so he is going to work on it more tomorrow. Thank you for your urging to look again!

NJ, I'm going to post a better picture of the scoop if I can figure out how Is this something we should consider replacing what kind of a task is it?
 
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