Air Bubbles In Baseboard Water Heater Pipes

rocklandguyZ8,SCMarch 13, 2008

Perhaps someone can help me save the cost of a service call! I have a gas boiler, 2 zone, hot water baseboard heating system. I "bleed" the three lines by running a hose out to the driveway and into a 5 gallon bucket. I turn off the butterfly purge valve, open the line faucet, then open the pressure valve. I do one at a time but do all three leaving the purge valves closed until they are all done. I let the water run until there are no bubbles coming up in the bucket outside. Then I shut off the pressure valve and close the line faucet, then open all three butterfly valves. The pressure comes up to 12 lbs cold to 22 lbs hot. This gets rid of the air noises in the radiators, but it seems to come back "too soon". I have already done this procedure three times this winter. Somthing must be wrong! I am thinking it is either the Amtrol Extrol, Model 30 and/or the Amtrol Float Type Air Vent, No 700, Max WP 45 PSI. Am I bleeding the system correctly, what does the Amtrol Extrol do, and does the Float Type Air Vent go bad? Here is a pic of what the system looks like. I would appreciate any help with my problem. Thanks!!!

Thank you for reporting this comment. Undo

Sorry, pic didn't come out the first time.

    Bookmark   March 13, 2008 at 7:47PM
Thank you for reporting this comment. Undo

well, it took two plumbers to get this done right, so I understand why you are having trouble. Was expensive but the last guy must have done it right. Sorry I can not be of more help.

    Bookmark   March 13, 2008 at 8:48PM
Thank you for reporting this comment. Undo

The fresh water you use to bleed with also contains air which will release fairly soon. Just let the system run for a week to try to release the air by itself, that's what the vent is for.

We also bled like you did except for the bucket. Our system had a Filltrol with extrol tank, air seperator and air vent. Ran it for a week and all the remaining air worked itself out.

    Bookmark   March 13, 2008 at 10:20PM
Thank you for reporting this comment. Undo

Did you remove the cap from the air vent and see if the Schraeder valve isn't gummed up? Depress it and see if some water comes out.

    Bookmark   March 14, 2008 at 5:45AM
Thank you for reporting this comment. Undo

Baymee, I just went down and removed the cap, depressed it, and nothing came out. The cap was 2 turns loose as the info plate stated. I guess I will have to replace that today. I'm sure it is not worth trying to fix or is there something I can do to ungum it? What about the Amtrol Extrol? How do I know if that is functioning properly?

    Bookmark   March 14, 2008 at 9:09AM
Thank you for reporting this comment. Undo

As stated above, "new water" will induce "new air". Baymee took you in the correct direction and you have verified a faulty valve. Change it out. With the feed valve closed, just reduce the water pressure to zero pressure. Don't drain the whole system.

The Extrol is working, if the pop-off (PRV) valve isn't activating.

There may be additional air vents on the outlet ends of the baseboard units

    Bookmark   March 14, 2008 at 10:40AM
Thank you for reporting this comment. Undo

Thanks tmajor, I went to the plumbing supply house and bought a Taco 400 HY-Vent, cost $8.03. Basically a more solid heavy duty full flow air vent, hopefully better than the old Amtrol 700. I just reduced the pressure to O like you said, removed the old, and put the new on, opened the cap, and now I will wait to see how it works. They told me the same thing at the plumbing store that the Extrol is working properly, and not to worry about it. It is really great to have people willing to help you out! Thanks.

    Bookmark   March 14, 2008 at 2:27PM
Thank you for reporting this comment. Undo

Is anyone else a little confused besides me about that filling arrangement? Normally with a bladder type tank you make up water into the return side. But if thats the case here the extrol is also in the return, hmmmmm! The pic. really isn't all that clear as to what part of the system this is but I really don't see what good that hi vent is doing where it is. I'd really like to see a better pic. of the total layout.

    Bookmark   March 14, 2008 at 8:50PM
Thank you for reporting this comment. Undo

I just looked at my system, which my plumber father-in-law installed 30 years ago. It's the same way. The boiler supply line comes out of the boiler to an air scoop with a vent above it and the fill-trol comes into the air scoop. The expansion tank is part of the fill-trol. I've never had any problems with it.

    Bookmark   March 15, 2008 at 7:30AM
Thank you for reporting this comment. Undo

Hi guys, Just read your follow-ups and took two more pics so you have a better idea of what I have. That's the new Taco vent sitting there. Maybe you have a better way, but this is the way the unit was installed. It seemed like a quiet nite last nite as far as the air in the baseboard radiators. Hope it stays that way. Don't mind the rack in front of the boiler, it is my germination rack for my garden veggies. Nice and warm there! Thanks again!

    Bookmark   March 15, 2008 at 10:50AM
Thank you for reporting this comment. Undo

The way it's plumbed, it will expel some of the air and hopefully, all the air eventually, but there should really be a horizontal air scoop installed to get out all the air.

    Bookmark   March 15, 2008 at 1:27PM
Thank you for reporting this comment. Undo

You're right baymee, but there's nothing to keep some of the air from hitting that el and going up the supply. But with a working hi vent now at least the system can vent some air. This thing should have an air scoop in a horizontal run though.

    Bookmark   March 15, 2008 at 9:40PM
Thank you for reporting this comment. Undo

I don't have a vent on my cold water fill line. I had one installed last fall and they put it on the hot water out vertical pipe right at the top where it makes its first bend. Never had a gurgle since.
Here it is.

    Bookmark   March 16, 2008 at 5:06PM
Thank you for reporting this comment. Undo

Any air vent will work, but with the air scoop it doesn't tend to rush by the elbow, but it still works.

Your installer will be red-faced when he realizes that the whole world can now see those horrendous solder joints. :)

    Bookmark   March 16, 2008 at 6:23PM
Thank you for reporting this comment. Undo

The solder joints on mine? LOL
I have to give him a pass, he was short and rotund and it's not in an easily accessible spot for him. Besides he was super knowledgeable, took time explaining and showing me how to work this thing before which I was totally clueless.

    Bookmark   March 16, 2008 at 8:28PM
Thank you for reporting this comment. Undo


I know it's been 8 months since you folks were discussing this, but hopefully one of you who seems to know these systems and their components will happen to see this follow-up --- your discussion was the best I've seen, and I'm hoping one of you can offer some ideas about my gurgling system.

I've bled all three loops in my system, both by doing what one plumber who worked on the system a few years ago called a "power purge" (hook up a garden hose to the drain valve for each loop and let water flow at full volume through the loop until the water flows smoothly, i.e. no more sputters) as well as using the bleeder valves in each loop. When I use the bleeders, no air sputters out, making me think I have all the air out of the loops.

But when the pump first kicks on in the morning, you'd think we were in a sub filling our dive chambers. The sound of water flowing in the pipes sounds like the system is empty and being charged.

The system did not have this problem last winter, but I drained it recently because I moved one of the baseboard radiators.

Having read all the earlier comments in this thread, I have an idea I'd like to run past people, but of course, I'm open to anything else anyone has to offer.

As it is, my Extrol is installed at the end of a dead end extension, contrary to the installation guidelines printed on the label. The reason I initially doubted that that's the problem is that the Extrol was that way last winter and the system was fine. However, the one possibility I'm wondering about is whether, when I drained the system a few weeks ago, too much air got up in the pipe that leads up to the Extrol, causing something like this to happen: after the system has been on a while, the air compresses up in the pipe that leads to the Extrol, and the system quiets down, but when the system is off for a while and the pressure in the system drops (because the boiler's not firing, i.e. overnight when we turn down the heat), the air de-compresses and pushes back down into the feed to the loops, thus causing a significant amount of gurgling when the pump first starts to push water through the loops; once the air has circulated back around to the tee that leads to the Extrol, the air is eventually all captured back up in the Extrol (and the pipe leading to it) and stays compressed there until the system pressure drops low enough to allow it back out of the pipe into the circulation feed.

Sounds completely whacked, I know, but I'm at a loss for how the bleeders can stream completely air-free water, i.e. no sputters whatsoever, but every morning, it sounds like there are huge air pockets in the pipes getting pushed room by room through the loop --- and then it stops.

Any thoughts or suggestions?



    Bookmark   November 21, 2008 at 5:09PM
Thank you for reporting this comment. Undo

Here is a new question: I have antifreeze in my pipes. Plumber recently had to drain it out to do a repair. Obviously lots of air in the system now. If I try to get air out, does system have a way to feed more water in to take up the vacated space? (It should be obvious I don't that much about these things)- any help appreciated. Thanx.

    Bookmark   November 3, 2010 at 6:42PM
Sign Up to comment
More Discussions
2 HVAC quotes: need to decide
I'm ignorant of HVAC, but willing to do the research...
Geothermal in new construction.
Our house is currently under construction, and while...
Is this HVAC system OK?
Replacing original old ~9 seer unit. House is 2001...
Thoughts on proposed HVAC system?
To start: my house is two-level (main plus upper)...
Climatemaster Tranquility 27 4 ton coil leak
I thought I'd noticed some degradation in the system...
Sponsored Products
Sealy Memory Foam Pillow
Grandin Road
RainShield Rectangular Table Cover
$139.50 | FRONTGATE
Michael McHale Designs | Tribeca Wall Sconce
$489.00 | YLighting
Traditional Column Radiator Cast Iron Style High Gloss Black 71 x 10.6
Hudson Reed
CAL Lighting Lamp Shades 18 in. White Vertical Piped Basic Bell Lamp Shade
$49.49 | Home Depot
Ainsley modern sectional sofa
Interior Define
1/2" IPS Heavy Duty 78" Shower Riser Pipe with 18" Arching Shower Arm
Signature Hardware
Designers Edge L4717 Directional Iron Pipe Size Threaded Dusk to Dawn Photo Cont
$29.79 | Hayneedle
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™