I have a Hot Water zoned heating system. All zones are flowing except for 2. The zones that are not circulating have air in them and they appear to have an air lock.

I have Radiant floor heat on the first 2 levels of the house and baseboard heat on the 3rd floor bedroom.

I had a circulating pump go out and had it replaced last week, the contractor said that we had a lot of air in the lines and opened a valve from the hot water heater to fill the lines back up with water (this valve is suppose to automatically do this but for some reason did not). He was concerned that the 3rd floor baseboard heat might have an air lock and stayed around after getting it going to make sure it was circulating. Well he thought it was and left. Well there is no water going through the baseboard. I have tried to bleed the lines but still no water flowing through them. The one baseboard has a steady stream of water flowing our of the bleeder valve when I open it up and the other one had a lot of air come out at first and now just a trickle of water comes out, nothing like the other baseboard.

I do have 2 circulating pumps (because our house is 3 levels), the contractor said that one is pushing the water and one is pulling. The water pressure says it is 35 psi. I know that's high but that's what it has been set for and there is a arrow on the pressure gauge that is pointing at the 40 psi mark, the pressure release valve is not leaking. I just had the release valve replaced last week when they replaced the circulating pump. I also have 3 taco automatic air bleed valves set up on the different lines by the heater. I also have 2 hose bibs on the system as well.

The one that bleeds well is the second in line. Should I keep bleeding it even if I am getting a stream of water through it?

Should I keep bleeding the one that not a lot is coming out of? If so how long? I can isolate every line and shut each one off should I shut all but the one I am trying to bleed?

I all so have hose bibs on the return lines and the out going lines, can I bleed one of them?

I have also noticed that one of the 2 bedrooms that is heated with the radiant floor heat is not getting warm. I have 2 bedrooms on the one line and one gets hot and the other one is not. I am assuming that I Might have an air lock in that room as well. Any suggestions?

I just spent $500 to have the circulating pump replaced and I don't have another $500 or $1,000 to spend on it now.

I live in Alaska and it is cold right now we are suppose to be running -40 to -45 all week and I would like to get all the heat working in the house.

To start with you have somewhat of a complex multizone system with a combination of baseboard and radiant heat. A three story also complicates the situation since you have to run a high water pressure.

You did not mention your water supply system. Is it a well or city service. The reason I ask is for the amount of oxygen entrainment and how long it will take the heat system to get the oxygen out of the water so it can be vented out of the system. When you do a first time bleed after adding large amounts of fresh water you will get most of the air but after the water heats up there will be additional air/oxygen that will be driven out of the water and that also has to be eventually gotton rid of by another bleed. This is why a good auto bleed is important and also why they sell pump isloation valves to prevent the water loss to start with.

In the perfect world there should be a auto vent on all circuits at the highest point to vent the air as it shows up but for some reason you may not have that. So here is what I propose.

Remember at all times you have to keep the water feed pressure up to the operating system normal level during bleeding. You said something about the fact that the auto fill was not working.

I had a circulating pump go out and had it replaced last week, the contractor said that we had a lot of air in the lines and opened a valve from the hot water heater to fill the lines back up with water (this valve is suppose to automatically do this but for some reason did not).

The valve that is not working should be replaced or someone is going to have to hand feed the system while you are bleeding since a drop in pressure can really mess up a system bleed especially if it is a 2nd or 3rd floor problem.

Try and locate the hose bib connection for each zone that is not working. Attach a drain hose and set it up in a way so the hose is in a bucket. Fill the bucket with water and put the hose in the bucket. Now when you bleed using the hose bib you will be able to see when the air stops bubbling in the bucket out of the zone you are bleeding. In other words no bubbles for a few minutes usually means there is no more air in the system. I usually do this two or three times for a few minutes each time just to make sure no more air bubbles show up in the bucket full of water that the hose is in. I hope this work can be done in the basement where the water will not make a mess. I have another tool that I made just in case the water can cause problems and that is a sight glass with hose bib connections. It is the same operating principle except you watch the large sight glass for signs of bubbled but the water flows through the hose to the outside of the home.

Try bleeding it in this fashion first to see if you have success. Remember three bleeds minimum and more if air still shows in the bucket.

You can isloate all the lines except the one you are bleeding if you wish since this might increase the flow on the line you are bleeding.

Boiler systems are complex and eash one is different so it is impossible for me to know exactly what to tell you to do since I cannot see exactly what is happening but this will give you a start. If you are on a well system with a pump you will usually have more air entrainment that with a city water supply and it will take a bit longer to get out the residual air after the system is up to temperature.

Keep us posted on the situation.

Thanks for the help. My questions are in red

If you have to make up a small hose. Get a bib, clamp and some tubing from a hardware store. It could even be clear tubing. Just coil the hose in the bottom of the bucket.

You don't need much water. Just enough to cover the hose, so you can see bubbles.

You can turn on. Turn off. And empty as many times as you like.

just have one hose bib on each side. I can turn off all the valves for each line that are not affected, would this work ok?

It should work but with not being there I cannot say for sure.

You said you have a basement so the mess if any will be there. I am sure the basement also has a drain.

I hate to say this but with a system like yours each circuit should have had a tap and drain configuration but you have to work with what you have.

Thanks for the help, got lucky last night and woke up to a warm room. The air must have worked through the line because I had heat in my room this morning!

I have been bleeding the valves and getting air out a little at a time.

Thanks again for your help.

Ron C

Sounds like it will all work out and that is a good deal since it is getting so cold where you are at. Post back if problems develop.