Hello, I've been trying to figure out how to bleed one of my heating zones. I think it has air because I've been hearing a gurgling noise for the last two weeks. It is just one or twice a day. I've been in this house for 3.5 years and I never bled the system. It's been serviced by the oil company once a year but when I called them about this they said they don't do this part. The furnace is about 12 years old.
I don't see any valves on the baseboards themselves. I read instructions here but I thought I would post some pictures for someone to tell me which valve is which.
The top, blue valve on the right is the shut-off for the main water pipe coming into the boiler, along with the one right below it. Not sure what the blue one at the bottom is for. All 3 blue ones have some kind of bleeding round knobs and I am not sure what they are for either. There are also 4 black ones that go to all the baseboards and I assume receive the hot water from the boiler. They all feel hot. They all have knobs underneath pointing down. Don't know what these are for. All 4 have hose attachments.
This system has 3 Zones as shown in the picture and the valves have "auto" and "open" on them.
The boiler pressure is at 20psi right now.
The expansion tank as you can see has the valve to pump more pressure into it.
Below this tank, on top of the boiler, there is a pipe that goes into it and has some kind of relief valve. I don't know what this is for either.
I assume the device by the blue valves is to relief pressure? (shaped like a bell).
I drained a bit of water from one of the black valves to make sure it was water and not antifreeze.
I am not sure what other info I can give you. I would appreciate if you can tell me how to bleed this specific system, or if you think I should just call a plumber. Please let me know if you need more pictures. Thank you in advance for your help.

Nelson

Here are a few more pictures. Thank you again.

Nelson

Unless you have bleeders on the baseboard heaters or in some other location your system will need a power bleed and I suggest you call a HVAC company that deals with boilers to do it or they will not know what they are doing. I do not have the time to type out the entire procedure and it really should be done by a pro.

You do have one auto air bleeder and it is above the pressure style expansion tank. The little cover should be left loose on that not tightened down.

I also noticed you have a oil burner so if it has not been tuned lately then I suggest you get that done at the same time. A new nozzle and oil filter will keep it running well and the air and barometric damper adjustments will save you some on the oil bill.

BTW the little levers under the spigots on the valves are to balance the system.

Thank you for your answer. Do you think the auto bleeder is bad then?
The noise through the pipes is not too bad. Is this something I don't have to worry about or could it damage other parts?

Do you think the auto bleeder is bad then?

No not bad what ever gave you the idea that I said it was bad?


The noise through the pipes is not too bad. Is this something I don't have to worry about or could it damage other parts?

I have no idea if you should worry about it or not. That is you to decide. All I know is that under normal circumstances there is no air in the lines to make the noise to start with. If you can live with the noise that is OK by me. If it gets worse you may end up with no heat in some sections but here again I have no control over that.

In my last post to you I told you exactly what I felt was necessary to get your boiler in good condition. I do not second guess myself.

Thank you.

No problem