Replacing Hydonic heat Air Bleeders


Old 03-21-19, 11:05 AM
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Replacing Hydonic heat Air Bleeders


My hydronic heat sytem has four zones. (three heat, one domestic hot water)
Three of the zones have Maid-O Mist #67 air bleeders. There is also a #67 bleeder on the top of the boiler.
I observed that the bleeders are pretty corroded and the valves are frozen on three of them. The forth one on the boiler leaks water if I loosen the "tire" cap.
Obviously, it's time to replace them.

I am not having air in system at this time.

Should i stick with the Maid-o-Mist #67 bleeders or would it be wise to use WATTS 1/8" FV-4M1 instead?

Old 03-21-19, 12:01 PM
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Your current air vents although acceptable are of lower quality than other vents on the market. I prefer the Taco which can be taken apart for maintenance if needed and an extremely well made vent. If you install a shutoff before each vent it can be isolated for maintenance or removal without draining. Below are some options and info.

You can tighten the caps to stop the leaks in the meantime without worry. They are not working anyway and you have a chance of sucking air into the system when the pump comes on in their present condition.

Hope this helps a little.
Old 03-22-19, 03:40 AM
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Adding to @Spotts answer, Honeywell Braugkmann makes a similar air vent and has a built-in shut off valve, can be taken apart to clean or rebuild, and can be bought from the same supplier
Old 03-22-19, 08:12 AM
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Jacobus - Maid-O-Mist MO67 air vents have high failure rates due to leaks. The tire type air valve has junk rubber gasket that goes after few years and cannot be replaced.

On see many pictures of Jacobus Maid-Of-Mist that leaked and cap had to be closed off to seal which also prevented further venting. See #1 post in this link:

Watts auto vents have bronze body that can be opened for servicing. Have 12 of them on my system. Only one had to be opened and cleaned.

Last edited by doughess; 03-22-19 at 08:47 AM.
Old 03-23-19, 07:01 AM
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Thanks Spott, Steamboy, and Doughess for your responses and suggestions with the URL's for possible replacements.

I'm going to replace with either TACO or WATTS

I'll repost after I make the switch.

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