Varivalve heatimer clogging

notch

When my house was built (1950) they ran a future pipe not tapped into the main steam line to an unfinished attic. Fast forward to 2022 and I finished the attic had the pipe connected and radiator installed. This fall I had to replace a clogged varivalve heat timer air vent because it was clogged. Now I am replacing the second one installed. Have not had trouble with varivalves in other radiators. Could it be the pipe sitting there dormant for 70yrs? Any suggestions on an air vent that clogs less and has a big vent (always had varivalve fully open). Thanks

Hap_Hazzard

What's it getting clogged with? Was the pipe capped at both ends or did they leave it open so small rodents could crawl in and die? If it was capped off, there shouldn't be anything in the pipe that would clog an air vent, and I'd start looking at the radiator.

dko

Opening the varivalve all the way is basically main venting.

notch

Pipe was capped originally. Not sure what was clogging it. Couldn’t blow through it. And leaving it in hot vinegar micmxture did nothing. Are varivalves prone to clogs?

Hap_Hazzard

I don't use them, but, looking at the diagram in the literature (see below), I'd expect them to be less prone to clogging than most other vents. The orifice is actually a slot rather than a hole, and it looks like working the adjustment back and forth a few times would clear any obstruction from the orifice. That's assuming that the obstruction is in the orifice, which seems most likely because it's the most restricted part of the flow path, but if you don't actually see any obstruction, and working the adjustment doesn't clear it, it must be somewhere else.

The next most likely place for an obstruction would be where the inlect makes the 90° turn—assuming that this is a right angle valve. Can you see anything when you look in the inlet?



I have to admit to being a little confused by their statement that "steam or condensation does not enter valve body." From the diagram it looks like the inlet goes right into the valve body, and if steam couldn't enter, how would it make the capsule expand? I have no clue what they mean by a "puppet." That's not a term I'm familiar with. If I were in your shoes, I'd dissect that thing and make a video to share. I know they're not cheap, but if you can't make it work, it's a loss anyway.

UPDATE: Looking again at the diagram, it looks like the inlet pipe is screwed into the valve body. If there's any chance you could unthread it, you might be able to see inside better without sacrificing the vent. They probably used a threadlocker, but give it a shot anyway. Don't heat it with a torch though. Anything hotter than steam will pop the capsule, and then you're done.

SteamingatMohawk

Artist's rendition, hopefully not the designer that knows what he is doing/saying.

Puppet most likely is poppet mispelled.

The statement about no steam in the body seems impossible, unless the assumption that the bellows will expand is because of "hot air" being pushed through the valve, coupled with thermal conduction heating up the valve body. It's a bit of a stretch of my imagination.

Long Beach Ed

We've had horrible experiences with hundreds of Vari-valves. The bellows disconnects from its top mounting causing the pin to fall into the orifice closing it forever. Of several hundred we installed in one year some 20 years ago, perhaps 20% failed in the first year and another 20% over the following years. Heat-timer wouldn't even discuss the problem, no less make good on their flawed product.

Put a Gorton C or D vent on it and be done with it all.

TwoTones

Yes! The varivalves are crap, besides venting too aggressively for most applications,  the bellows disconnect and make them not vent in about 60 percent of them.   If you shake it and it rattles then it won’t vent anymore.  Crap design…