How do I bleed air from my baseboard heat / boiler

rodney23

Hey all,

I just finished up re-piping an area of the baseboard heat in a bathroom. I got the zone drained just fine to make the changes, but now that I've got it all back together... I'm having issues getting heat to that zone. I get some heat... but not quickly and not as hot as the other zones that were not worked on. FYI... the zone I worked on was to the top floor of a 2-story house.

After researching, I'm pretty sure that my problem is air in the pipes that I need to purge. However, I can't figure out how to do it with the configuration of pipes and my boiler. I'm hoping someone here can point me in the right direction. Also... I do not have bleeder valves on any of the slant-fin baseboard radiators... so I cannot bleed the system that way.

I've taken some pics and posted them here: pic 1, pic 2. It's a 4-zone system with a weil-mclain oil boiler. In pic 1, you can see the feed pipe coming into the system (yellow valve) and going down to the back-flow preventer and expansion tank. You can also see the 4 zones. There's also what I believe is an auto-air vent (silver, next to the circulator on top of the boiler).

In pic 2, you can see everything again from a different angle, as well as the boiler drain at the bottom right.

From what I've been reading from other posts... I think what I need to do is run a hose from the boiler drain, set the valve from "auto" to "open" to for the zone in question, open the boiler drain, and let it run out for a while? Am I missing something? Would the auto-air vent eventually let the air out of the system? Thanks for the help!

~Allan

beenthere

Your way, will not work. The hose would be attached tot eh purge valve just above the zone valve. And the zone valve does not get opened.

Your system is set up for a reverse purge.

rodney23

Can you explain that a little more?

Are you saying that in my system... water actually flows up from the circulator on the right hand side of the boiler and comes back down (returns) through each of the 4 pipes, past the zone valve and back into the boiler?

If so... I understand that I'd attach the hose and open the valve just above the zone valve. But how would I move water through the system to force the air out of the hose? I thought the only way to get the circulator going was to open one of the zones?

Thanks for the help!

rodney23

Ok,

I drained the zone in question via the hose bib just above the zone valve. I heard water coming in to the system via the fill pipe. I got some spurts of air just after I opened the valve and once or twice within the first 10 seconds of the valve being open.

However... after that... I wasn't getting much coming out of the purge valve. I tried closing the valve... giving it a minute or two and then opening it again. I would get water again for a little bit... but not too much. It almost seems as though the pressure coming into the system via the fill valve wasn't enough to force the air through and out of the system.

So.... the million dollar question is... what do I do now?

I tried opening the purge valves on the other zones for a comparison, and I got a decent flow out of them... nothing torrential, but steady.

My fill valve is an auto-fill... seems to shut itself off at pressure, so I'm not sure I can put more force into the system to try and push the air out. My boiler reads about 18 psi, was the same now as it was before I started my work (I checked before draining).

As before, I am getting heat to the zone... but I can hear the air gurgling through the pipes and the heat comes and goes at the spots I'm checking. I'm assuming that's from the air moving through the system. Hmm... if its moving through the system with the heat on, that must mean the circulator is adding enough pressure to push it around. I guess I could purge with the system running... if it weren't for the scalding hot water it would probably work?

Appreciate any suggestions!

~Allan

beenthere

Does the auto fill have a quick fill lever? If it does. Then using it will over ride the auto fill's shut off pressure setting. And put water in the system faster

If ti does have a quick fill lever. Use a utility hose and fill it from a faucet in the room.

rodney23

beenthere,

Thank you!

While I knew the system had an auto-fill valve, because I could hear it working, I hadn't yet looked for it and seen the lever on top. Sure enough, I pull the lever and I hear the water flowing into the system and the pressure going up.

So, tomorrow I can try one last time to push the air out of the system using the quick-fill lever, all while keeping the pressure where its supposed to be.

Thanks for the help!

~ Allan