Closed hydronic system with standard expansion tank and auto vents
Closed hydronic system with standard expansion tank and auto vents
(OP)
Just a sanity check here. Having auto vents on a system with a standard expansion tank is just asking for trouble, correct? Eventually the air will all purge out and you will flood the tank and pop reliefs, right?
With bladder/diaphragm tanks, on the other hand, you do want auto vents.
I'm looking at a remodel job where they are calling for the re-use of standard expansion tanks, but they are also calling for auto vents all over the place. I am going to bring it to the engineer's attention, but I want to double-check first.
With bladder/diaphragm tanks, on the other hand, you do want auto vents.
I'm looking at a remodel job where they are calling for the re-use of standard expansion tanks, but they are also calling for auto vents all over the place. I am going to bring it to the engineer's attention, but I want to double-check first.





RE: Closed hydronic system with standard expansion tank and auto vents
RE: Closed hydronic system with standard expansion tank and auto vents
RE: Closed hydronic system with standard expansion tank and auto vents
Auto vents shouldn't have any effect on the tank, as they primarily handle the air elimination on initial fill. The air separator & expansion tank handle the disolved air that comes in with the water.
The the air separator & expansion tank should be located between the boiler outlet and the circ pump suction. This puts the air separator at the point of highest water temp, and lowest pressure - which allows any disolved air to pop out of solution, and be directed to the expansion tank, where it will stay - pretty much forever. The make-up water connection should be located between the air separator and the expansion tank.
Bell & Gossett has some excellent literature on this.
RE: Closed hydronic system with standard expansion tank and auto vents
RE: Closed hydronic system with standard expansion tank and auto vents
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RE: Closed hydronic system with standard expansion tank and auto vents
Auto-air vents spit. Depending on location, a spitting auto-air vent could cause a world of problems.