automatic air vents- good/bad?

Joe Mattiello

Attached is the submittal data information for the Taco, hy-vents.

Taco, Inc.
Joe Mattiello
Technical Service Technician
joemat@taco-hvac.com
401-942-8000 X 484
www.taco-hvac.com

DavidJ

Considering replacing manual air vents with automatic ones on top floor radiators. Existing key vent valves are attached to panels and connected to the radiator with 1/8" copper tubing. 50 years of removing the panels to clean is resulting in joint failures. Since the radiators are units behind panels a failed auto vent would not be noticed until the water showed up in the plaster below.

Appreciate your thoughts/recommendations on reliability and brands.

Steamhead

Automatic vents

can be problematic if the circulator is on the return line, pumping into the boiler. This setup can depressurize the system enough that auto vents will actually suck air in!

If the circ is on the supply line leaving the boiler, pumping away from a good air separator, with the expansion tank connected to the system at the separator, auto vents would work OK. But you really wouldn't need them, since the separator would eliminate the air before it got to your convectors.

If the circ is on the return, why not have one of us change it to Pumpiing Away? Then you could use whatever you want on the convectors. Try the Find a Professional page of this site.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

DavidJ

The boiler, controls, and circulators are new with the highest zone tied into the old copper mono-flo loop. The radiators are above the circulator so the lines too and from the radiators (as well as the radiator) hold air real well.

The circulator pumps are pumping away from the boiler with the Spirovent air eliminator located between the boiler and the pumps. The expansion tank is located on the supply line just before the boiler.

With this set up and the old mono-flo lines, do you think I can do away with the bleed valves? I guess I could just partially drain the system and see if I get air locks in the radiators when it is refilled!

Thanks for replying.

DavidJ

Steamhead

In this case

I'd go with automatics. They won't draw air in since you're Pumping Away, and won't be damaged when removing covers for cleaning. I like the Taco Hy-Vent and similar B&G model with cast (not stamped) body.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

DavidJ

Many thanks for the advice.

Davidj

Jerry Boulanger_2

My belief

is that there should only be one good quality automatic air vent in a system with a pre-charged tank, and it should be on the air separation device. Auto air vents are potential leaks, which are a slow death for a closed system. If there are other auto air vents installed in some locations for convenience they should be valved off most of the time.

jeff_51

if you dcide to use auto vents

use the little isolation petcocks. The autovents work well, but do fail and need to be replaced every couple of years. This way, you don't have to put the whole system down, or if one starts to leak, shut it off