Hydronic Mystery Valve

MikeTsu

Hi, I heard some gurgling sounds come from my Hydronic Heating system when it turned on recently and checked to find out the issue. I had recently replaced a pressure relief valve and had some issues isolating it with all the switches so I figured some air must have entered the system. I have been searching for an air bleeding valve for an hour before I stumbled onto this big brass thing on a pipe. It is not labeled or engraved with any markings. Is this the air purge? If it is how do I use it? The boiler set up goes as follows:

Boiler
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This Mystery Item
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Expansion tank
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Baseboard Heaters
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Zone Control Valves
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Bleeder Valve (Yes, singular for 4 zones. Don't know why they set it up like that)
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Inlet for cold water
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Watts 9D-M3 dual check backflow preventer
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Pressure Reducer
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Taco 007 Pump
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Boiler

Ironman

That's the Micro Bubble Resorber or "air purger".

The brass outlet cap should be open about one turn and the device will work automatically, provided that the float is not stuck.

The top half will unscrew to provide access to the float assembly for cleaning or replacement if needed.

Of course, you'll have to relieve the system pressure and drain it to that level if there are no isolation valves.

MikeTsu

I'll have to look online to find a manual for the Resorber and figure out how to unscrew the outlet cap. I just tried with a pair of channel locks and applied moderate pressure and it didn't move.

Ironman

It's a SpiroVent and you need a pipe wrench.

JUGHNE

Make that 2 pipe wrenches...I would recommend

hot_rod

MikeTsu said:

I'll have to look online to find a manual for the Resorber and figure out how to unscrew the outlet cap. I just tried with a pair of channel locks and applied moderate pressure and it didn't move.

Bob mentioned disassembly at the middle seam.

That small top vent thread assembly doesn't come apart easily, or allow access to the float.