DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   HVAC (
-   -   how to bleed air out of hot water baseboard (

newhomenj 12-10-2011 11:02 PM

how to bleed air out of hot water baseboard
5 Attachment(s)
hi everyone, I read several blogs but still not sure how to take out air from my hot water baseboard. I am attaching a few photos if someone could give me step by step instructions to how to take the air out.

I have a 2 zone heat , zone 1 is 1st floor which works great, its the 2nd floor where i can hear the water in the pipes.
i know a few ppl have a valve in the baseboard but i do not have that valve.


HVACDave 12-10-2011 11:27 PM

What do you have for pressure in your system? Looks like there is some by the gage, but it may be stuck. If you pull the covers off of your baseboards upstairs you don't see any place that you could bleed off any air? Is there a union or a tee with a cap, or anything like that? Some of the vents are really small, could you take a picture of what type of rads you have?

how 12-10-2011 11:57 PM

If you have no bleed valves on your baseboards, then trying to drain the air out of your system the way it is now set up might well be a waste of time. I am 95% sure that you will not have a union joint upstairs on a baseboard heating system that you can crack to let the water pressure force the air out. (I'd check for that 5 % chance)
This means that you can only try to force the air back down and out to a drain with house or street water pressure. The replacement water will be oxygenated and soon release more air back into the upstairs baseboards so you'll be back where you were.

The main problem is your auto bleed valve is situated on the boiler on a dead leg to the T&P valve where it can't do its job of removing air from your system. Until a auto bleed valve or a spiro vent gets installed on an active part of your water circulation system, your air problems will just continue.

Is this air preventing you from getting the heat where you want it ,when you want it? Is your T&P valve venting? What does the working pressure and temp read on your tridicator guage. Is it just the noice issue at present?

REP 12-11-2011 01:35 AM

Whoever piped that boiler should be put in prison for flat out stealing your money.
So many things,,,,,,,,,,,,,,,,,,,,,,First it looks like the boiler is piped with 3/4" copper.If thats the case 3/4" is good for about 40,000 btus unless you play with the water temp above 180 degrees.Second I do not see an air scoop.As already mentioned the air vent you have is on a non water moving part of the piping.
You can pressure feed that boiler all night and you will stillo have air in the system.Third you have your low water cut off before the pressure reduser,that will not work.
What you need is a boiler guy to repipe your boiler if you ever want to have any level of first safty and second comfort.
You are going to need an air scoop so get ONLY a Spirotherm air scoop.The rest of them are 70 year old technology and don't compare to the Spriotherm.

beenthere 12-11-2011 04:54 AM

Not pipe up the best, but you do have purge valves to purge the air out at least.

biggles 12-11-2011 05:08 AM

manually swing the 2 zone valves if you can no circulator running close off the 2 ball valves on the horizontal piping connect a hose and drain off the zone letting the water feed push the air out then do the other.reopen the ball valves and restart the boiler.i bleed vent on each zone as it turns onto the floor above will solve all of this and that bleeder relocation..also might want to add a nipple and bal valve below that EX tank for future drain outs or repairs

newhomenj 12-11-2011 12:23 PM

thank everyone for such a fast reply

I just checked all the baseboard pipes on the second floor ...there are no union or vent to get the air out.. so i guess the only way is to drain the water out

1. turn off the boiler
2. connect the hose to the second zone
3. turn off the valve from where the water is going to the second floor from the pump
3. make the pump on manual mode (that small silver box connected to the pipe)
4. open the valve to let some water out

not how much water do i take out.. and am i missing any step or i am way wrong on the above steps...


biggles 12-11-2011 12:29 PM

you don't want the circulator on let the auto feed push the air out toggle off the boiler and maually swing the zone actuator shut the riser ball valve so the onlt outlet for the feed water is that petcock and out the hose...till you don't here any air it will burp some then shut that zone and do the same with the other hose and valves

how 12-11-2011 12:37 PM

Is your system not working properly now?

Remember that all the relatively oxygen inert water that goes down your drain will be replaced with freshly oxygenated water.
Without a system to selectly bleed the air out of the boiler that doesn't require the refilling of it with fresh water, you are just not going to be happy with the result a month down the road.
That continuous air in the system will be internally rusting away that black iron piping and the expenses for replacing the eventual debris damaged equipement will exceed the costs of properly installing an auto air bleed valve.

REP 12-11-2011 03:04 PM

You can do whatever you like,but until somebody properly pipes this boiler you will not get much more than 40,000 btu into house.I hope you hyave a small house like 700-800 sq feet.
The way it is now there is no way to get the air out.You might be able to dislodge an "air bubble" but you will have air in the system.
The way it is now the water to the house would have to be shut offr in order for the low water cut off to work and shut the boiler down.
Perhaps you missed my earlier post.Your piping is a total mess,it will not work properly the way it is.

beenthere 12-11-2011 03:26 PM

Hook garden hose up to faucet on return. turn off boiler. Close ball valve between where hose is connected and return pipe. Open faucet. Manually open zone valve. Pull fast fill lever on auto feed up so it feeds water quicker. Purge for several minutes until you no longer get air out of it. then release fast fill lever, close faucet, and open valve between faucet and return, put zone valve back to auto, repeat for other zone if it has air in it also.

newhomenj 12-12-2011 06:22 PM

2 Attachment(s)
hi, I just noticed something few ppl on the forum said that the normal psi is between 12-25, i just checked mine and it was about 50 ( attaching the image)... i have both the zones on and i took the photo

Also when i drain the water "Pull fast fill lever on auto feed up so it feeds water quicker" so that is the second image the i have attached right, looks like a bell that's the thing i need to trun when i drain the water right?


how 12-12-2011 06:28 PM

OK , that means that you have at least one more faulty part on your boiler. The T&P valve that should vent as a safety control when your pressure raises above 30 PSI or your pressure guage is giving a faulty reading.

biggles 12-12-2011 07:28 PM

that BELL is your auto feed set at 12psi to stop the city water when it reaches the 12psi.when you lift it your over pressurizing the system from the street blow the water off the boiler till you here the auto feed start to make up it should stop feeding around 12 psi then start the boiler that 12psi minus the 30 relief is plenty of room for the water to heat up to satisfy the stat and should end up around 20 psi or a little over... don't ever tounch that water regualtor...let it do its job that's why your up into the 50 psi range on the boiler...its looking at city pressure into the house it doesn't need it....just that 12psi which is universal with all residential boilers to at least have a standing water pressure thru out the entire system in the house..even when you bleed any place as you originally where looking to do that regualtor will continue to feed till it reaches 12psi as it pushes the air repeat your entire piping system thru out the house is at 12psi on a cold boiler before the stat calls

beenthere 12-12-2011 07:48 PM


Originally Posted by how (Post 792370)
OK , that means that you have at least one more faulty part on your boiler. The T&P valve that should vent as a safety control when your pressure raises above 30 PSI or your pressure guage is giving a faulty reading.

Boilers don't have T&Ps. Just pressure relief valve.

He needs to check what PSIG his relief is set to open at. And his gauge may be incorrect as you said.

All times are GMT -5. The time now is 04:59 PM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1