Zone Valve + Temp Controller = Main Vent?

TonKa

You can't vent faster than an open pipe, right?

Considering the cost of The Gorton #2 and that people frequently use more than one in a "moose antler" setup, wouldn't a fast, actuated ball valve and a temperature controller (plus a well placed temp sensor) be almost an ideal main vent? Set it to close at, say, 200 degrees and open at 180, wouldn't it pretty much work like a a gigantic main vent?

If so, why isn't this done more often? For that matter, why isn't this setup sold as a main vent?

If someone has done this successfully (residential or small commercial), what did you use for the valve, temperature controller, and settings?

pedmec

Other than the cost you mean? Maybe because if it fails open your in a really bad predicament.

Jamie Hall

KISS.

You would need power for the valve and sensors. You would need both temperature and moisture sensors (vents have to close against water, too). You'd need to make it fail operational (no mean feat).

Sometimes whizzy isn't better.

TonKa

As mentioned, considering the cost of two Gorton #2s, a zone valve & temp controller would be competitive.

It is my understanding that the Barnes and Jones Big Mouth main will spit water, so I don't see how this would be all that different. Anyway, if water is reaching a properly placed main vent, aren't there bigger problems? (Regardless, needing a moisture sensor is hardly a huge complication.)

As far as failing "operational", I assume you mean fail closed? A normally closed, spring return valve would fit the bill, no? (And, it's not like steam vents haven't been known to fail open, too.)

As far as power, I have 24vac for the boiler controls & thermostat anyway.

I can't be the only one who has thought of this, yet when I skimmed through the topic titles on this forum, I didn't come across this idea discussed. Still, I seem to recall @ChrisJ mention in passing on another thread he was using something like this, though I lost track of that post.

I guess I'm really looking for a sanity check. There isn't much point if a few others have tried this and disaster ensued.

Jamie Hall

Yes, Big Mouths don't close against water -- which is why I can't recommend using them, except in unfinished spaces where water damage is not a problem. Not when there is an equally simple device which has a float in it to prevent the problem.

Fail operational, in this instance, could mean fail closed, depending somewhat on the system. Some systems do moderately well with closed main vents -- most one pipe systems, for instance. They will be rather unbalanced, but will work. Many two pipe systems simply won't work at all, as the main vent is the only vent. Fail open is obviously unacceptable.

I might point out, perhaps in passing, that a two pipe vapour system -- with orifices and traps (at least crossover traps)-- works perfectly well with just an open pipe, however, The vent in those systems is part of the mechanism which prevents overpressure from causing problems, and is not really needed for normal operation.