Better Bleeding


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Old 10-16-09, 06:40 AM
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Better Bleeding

I'm in the process of piping HW baseboards in my home. This has been an ongoing changeout from electric basebd to hw basebd. There are a couple of zones that I have no choice in having some ups and downs in the piping. These are series loops. I know this will cause some air issues. Would I be better served to install those small auto air eliminators (that will fit behind the baseboard access cover) at the high points or just bleeder valves.
Thanks
 
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Old 10-16-09, 06:46 AM
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Proper air elimination at the unit and a good flush/purge at install with proper circulation and there is no need for bleeding air at any time.

If you do install BB tees to bleed air, install manuals, autovents are destined to leak, besides under many conditions especially at high points can add air also.
 
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Old 10-16-09, 02:01 PM
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Better Bleeding

ZL700 what is your procedure for proper air elimination and a
good flush/purge?
 
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Old 10-16-09, 03:26 PM
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Agree with ZL, NOT the automatic variety.

IMHO, to _not_ install manual bleeders is not a good idea.



Referring to the above pic, placing a manual bleeder wherever the pipe turns downward will allow you to easily get the air out. Bleeders at these locations are best used with the circulator pump RUNNING, because it will push the air to those locations. You can (and probably should) also install them at any very obvious high spots in the piping, and these would be best opened with the pump NOT running, and after the system has been at rest for some time, allowing the air bubbles to 'float' to those locations.

The problem with 'power purging' the system to remove the air is that the fresh water you are adding to the system contains dissolved oxygen and once the water is heated that air will come out of solution in the water, and you are often right back where you started.

You obviously will also be installing a new boiler, and attention should be paid to the location of the expansion tank and 'air scoop' in relation to the circulator pump. Google up "Pumping Away" or use the search function here for more information on that.
 
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Old 10-19-09, 11:16 AM
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Thank you both for your help
 
 

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