Can get the air out of my system

salisboss

I have a gas converted oil combo boiler. It heats the water for my tap water and three zone hydronic heating system. The last three years I have had to purge the air from my zones at the beginning of each heating season. This year I can't get the air out. The air seems to collect in one zone. It is better but I can still hear trickling in the pipes. Below is a picture of the supply side but my return side consists of three motorized zone valves and a circulator pump. From what I have read it is apparent that the air scoop is too close to the pipe joints. Also the stupid auto vents don't actually release any air unless I push down on the needle then it spurts. The cap is left loose. I haven't checked the expansion tank pressure but by tapping on the tank it sounds as if it is evenly split between air and water and properly pressurized.

In addition to figuring out why I can't get all the air out would it beneficial to take out the air scoop and put in a spirovent?

EBEBRATT-Ed

I would

Take the air scoop out and put in a Spirovent

Move the circulator to the supply pipe downstream of the new spirovent.

leave the zone valves as is

Try opening the flow check valve while venting ...in fact you probably don't need the flow check valve at all.

Intplm.

@salisboss do this as mentioned ^^^^^^^^above^^^^^^👈👍🏼

STEVEusaPA

@EBEBRATT-Ed nailed it...

salisboss

> @EBEBRATT-Ed said:
> I would
>
> Take the air scoop out and put in a Spirovent
>
> Move the circulator to the supply pipe downstream of the new spirovent.
>
> leave the zone valves as is
>
> Try opening the flow check valve while venting ...in fact you probably don't need the flow check valve at all.

Sorry for my stupidity but what is the flow check valve? Also how would I open it?

EdTheHeaterMan

The flow check looks like this,


It is at the top of the supply outlet and is being used as a 90° elbow in your system to turn horizontal to the air scoop (with rust below the vent)

Also the small handle at the top will open the valve if turned counter clockwise. Turn it clockwise to put it back to automatic. You may get gravity flow to some radiator loops if left open.

EdTheHeaterMan

Follow up:
it appears that the handle on your flow check may already be partially from closer examination of the picture. or it could just be the way the handle is.

The concept of the valve is to keep heat from flowing (by gravity) into the radiation system when the boiler is maintaining heat for Domestic Hot Water (DHW). When the circulator operates by a call for heat from a thermostat, the force of the pump will automatically open to allow heat to the room's radiation system.

BTW,
@EBEBRATT-Ed , @Intplm. and @STEVEusaPA are all on the same page because of the Physics of Water and some old friends of @DanHolohan (the guy who started this site)
Henry's Law and Boyle's Law explain why the air is going to the wrong place. and how the above suggestions will resolve issue.

this is a diagram of what we are talking about



before you start this project, read up on the concept in a book called Pumping Away
available on this site at THE STORE

salisboss

> @EdTheHeaterMan said:
> Follow up:
> it appears that the handle on your flow check may already be partially from closer examination of the picture. or it could just be the way the handle is.
>
> The concept of the valve is to keep heat from flowing (by gravity) into the radiation system when the boiler is maintaining heat for Domestic Hot Water (DHW). When the circulator operates by a call for heat from a thermostat, the force of the pump will automatically open to allow heat to the room's radiation system.
>
> BTW,
> @EBEBRATT-Ed , @Intplm. and @STEVEusaPA are all on the same page because of the Physics of Water and some old friends of @DanHolohan (the guy who started this site)
> Henry's Law and Boyle's Law explain why the air is going to the wrong place. and how the above suggestions will resolve issue.
>
> this is a diagram of what we are talking about
>
> (Image)
>
>
> before you start this project, read up on the concept in a book called Pumping Away
> available on this site at THE STORE

Thanks everybody for your help.

salisboss

I bought and read Pumping Away and I think I have summer project.

Along with the air issue and it may be linked but the auto vent on the air scoop keeps filling with water. Is this normal? If I push on the needle it just spits water. Also can an air scoop go bad? I know it won't work optimally until I move the pump but the air seems to be worse this year that in the past .

hot_rod

Scoops don't go bad the auto vents do.

Scoops are rotary phone technology, Microbubble purgers are much better

Really should not push that needle in, those vents are designed to have a small air space up top. When you push the needle in and bring water up, often you get debris in the valve mechanism and they drip, drip, drip.

If you want to burp it, loosen the vent at it threaded connection at the bottom.

salisboss

So I probably ruined it by pushing on the needle good to know.

hot_rod

maybe not, it it stops dripping you are probably fine.

It could be the piping arrangement causing air removal issues. What is the pressure on the boiler gauge? Sometimes adding a few more psi helps rid the air faster. it squeezes trapped bubbles smaller so they flush back to the purger.

mattmia2

You could probably close one of those isolation valves and open one zone at a time and use the water feed to force purge each zone out to one of the boiler drains.

salisboss

> @mattmia2 said:
> You could probably close one of those isolation valves and open one zone at a time and use the water feed to force purge each zone out to one of the boiler drains.

That's what I have been doing but I am not getting all the air out. Last year I purged at the beginning of the season and it was fine until I turned the heat on this fall after it being off all summer.

HomerJSmith

How do you purge the baseboard (an assumption) to get the air out.

I would close the valve over your expansion tank and un-hook the tank and check the air charge and fill the air bladder side to 15psi. If water comes out of the tire valve on the bottom of the tank, replace the tank. Use a cheap digital tire gauge to measure the pressure.
The sys pressure fill valve should be set at the same pressure as the bladder tank.
Over time, the air scoop will eliminate most of the air in the fluid. The micro bubbler will do it faster.

mattmia2

Did you open the check valve and the fast fill lever when you purged the problem zone?

salisboss

> @mattmia2 said:
> Did you open the check valve and the fast fill lever when you purged the problem zone?

Fast fill yes. I didn't touch the check valve but as far I can tell it is basically an elbow.

John Abbott

What is the 5 gal pail full of water? is it under the PR valve collecting discharge?