# bleed a multizone hydronic heat system



## Marvin Gardens (Sep 30, 2008)

jsamorug said:


> How do I bleed a hydronic heating system with 2 zones and 1 circulator and "in line" zone valves with bleeders for each loop after each zone valve?


First off do it when it is cool. No need to burn yourself.

Next pressurize the system with replacement water so you don't introduce more air. Open up the bleeder valve and keep it open till nothing but water comes out. Close the valve and repeat on the second zone.

By the way the zone valves should be open to make this work.

My question is why are you bleeding this? Recent repair, leak, new instillation????

You should have an air scoop in there that would pull out the air as it circulates.


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## jsamorug (Oct 4, 2008)

Thanks for the reply. 

First of all, the is no air scoop on the system. I am doing this because the system is getting progressively worse with gurgling, etc.

Secondly, on second zone there are four bleeder valves for each of the four loops on that zone. Do I need to shut down the other three loops and bleed one at a time?


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## Marvin Gardens (Sep 30, 2008)

jsamorug said:


> Thanks for the reply.
> 
> First of all, the is no air scoop on the system. I am doing this because the system is getting progressively worse with gurgling, etc.
> 
> Secondly, on second zone there are four bleeder valves for each of the four loops on that zone. Do I need to shut down the other three loops and bleed one at a time?


There should be a bleeder that is higher than the rest of the system. This is your high point and that is where I would start. Bleed them all since there is no disadvantage to bleeding unless you have propylene glycol in which case you would have to replace it and that is a chore.

Is yous system pex?

I suggest getting an air scoop and put that in. They will get rid if excess air and you shouldn't have to bleed the system after that.


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## jsamorug (Oct 4, 2008)

Please see photos titled "Heating System". This will show the bleeders in my system. There are six of them all at basement level. They appear to be on the return side of the loop. Hope that helps.


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## Marvin Gardens (Sep 30, 2008)

Interesting. Air rises and the bleeders are on the bottom. Is there a place where there is a high point with a bleeder?

Also is the whole thing copper, even the floor heating part? If that is the case then I would want to find out why is it gurgling all of a sudden.

With non barrier pex there is an transfer or oxygen through the pipe and it will get more and more air till it will really makes some noise. For non barrier pex the air scoop is essential. In copper I can't imagine where air is getting into the system unless there is a leak somewhere.


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