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Water not flowing in Baseboard heat

6612 Views 9 Replies 5 Participants Last post by  cmorales
My problem is a lack of flow though one of 4 zones, baseboard heat. The other 3 work fine, the circulater pump is fine and I have observed the solenoid valve open and close as well.

Background... I had a leak from my water jacket today. I closed the water supply and the 4 zone return lines and drained the furnace so I could do an emergency JB weld repair... the repair is holding. But I lost heat in one of the zones.. It was working before.

I made a short video explaining the issue and put it on youtube and I will put it in a follow up post... rules won't let me put it here in my first post...

Please, any suggestions would be great! Is an air pocket the problem? How can you bleed air out without bleed screws!?
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Here is the video link...


Thanks! Zach
Best way to purge system of air is start at first floor and work your way to the top floor.

Turn off boiler. Close all those zone ball valves and hose bibs, override valve you're bleeding and make sure you put it back to the auto position when done.

Hook garden hose to first floor zone hose bib and run outside, sink, or bucket. Open first floor zone ball valve only, open hose bib let run till you get a full stream of water coming out of hose with no air.

Once all air is out, close hose bib, remove hose, remember to put manual overide back to auto. Repeat with rest of the zones if needed.

The point to remember is open the zone valve of the zone you're purging, the others stay closed during purging.

Click on video for additional info. Hope you get it running soon.

If it's still not working, or still having trouble, please wait for the hvac techs to respond. Thanks.


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That zone probably didn't drain completely. And froze before you were done with the repair.

Leave the drain valve open like you had it. Eventually, the ice will thaw/melt. Connect a garden hose to it to drain it out to a drain instead of a bucket, less mess that way when it thaws and gushes water out.
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ok, first call Weil McClain, the sections of the boiler should still be covered under warranty.see what they can do for you on the boiler repair...now onto the no heat,if you open the bleeder valve and dont get flow through the loop at all by manually bleeding, you probably like mentioned above have a frozen spot in the loop, not good, you should try and find that area and insulate, a heat gun will help defrost the pipe or hire someone with a pipe thawing machine...
Thanks 'cmorales' and 'jmon'. I woke up, watched the video and went to purge the air.. I had full flow right away and no air to speak of. So I think 'beenthere' was correct. I must have had a section of the pipe freeze. That particular loop runs through a sofit in my unheated garage before heating my family room, which never gets hot enough... bad system design, but freezing causing lack of flow makes sense.

'ShtRnsdownhill' As far as warranty, I'm the second owner, bought this house a year ago. so technically the warranty doesn't transfer. But even if it did, Weil McClain would have only covered 25% of parts b/c the boiler is over 25 yrs old. At this point I'm hoping to limp through the winter and replace at my leisure when the weather warms up.

Thanks!! I'm up and running, staying warm:smile:
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You're welcome. Glad everything worked out for you z and you have heat now.
they make a boiler sealer that you add to the water that might help to prevent future leaks in the boiler..it fills in the crack when one develops...but if its all running good now..wait till spring to mess more with it..
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