Experiencing a high failure rate with air vents, why?

yyou_stinka

I’m currently using a mix of Hoffman “40” and Vent-Rite, adjustable and fixed air vents, mostly because of limited asscess to supplies. Also trying to find a reliable vent.
I have a one-pipe, Dunkurk system that came with the house we bought almost 3 years ago. I have the system serviced annually. As far as I know, the 1-2 main vents are working properly.

What I’m finding is the air vents seem to remain open too long, collect water and seem to fail. In fact I had 4 vents fail at once and released steam all night, by morning my 3rd floor was a delightful sauna and my boiler ran out of water. Clearly not ideal or sustainable.
The Vent-rite tongues are not fixed into position, so maybe the water cannot drain away properly when the vent/radiator are cool?
Some vents will last a season, others only hours or days. As I am a rookie with limited knowledge of these systems, I don’t even know how long a vent should last. Unlike with more conventional HVAC, I know I should replace the filter every 3 months, on average.
Any insights and recommendations would be most appreciated! Thank you!

Jamie Hall

What pressure does your system reach on its cycles? High pressure can cause your problem.

pecmsg

collecting water is a sign of wet steam.
agreed what is the operation pressure

Mad Dog_2

Wet Steam.my friend. Mad Dog

yyou_stinka

@pecmsg ,@Jamie Hall & @Mad Dog_2, to my awareness my system is set to .5psi, about as low as the gauge will go. When the vents work correctly, the steam is dry and a tank of water will last 4 weeks consistently. For a one pipe system, relatively quite all around, with less water hammer. When the vents fail, it gets a lot noisier, which in turn allows for more water in the system, as they vent too much steam. Which is why I’m on the hunt for a reliable brand of vents.

The company who services my boiler is G.W. Gill Plumbing, the best in the area and one of the best in the industry. I’m confident if my pressure was too high, I would have heard about it before now.

mattmia2

the water in the wet steam drains back to the boiler, it isn't lost except in the part that is spit out the vents.

should be no water hammer.

wet steam can be caused by improper near boiler piping or water quality problems causing surging or priming.

yyou_stinka

@mattmia2 yes generally speaking most of the water drains back to the boiler in between cycles. To your point, we are considering paying to have some of the original pipes removed, directly above and connected to our boiler this summer. The thought being it will be a good time to flush the system of accumulated rust and hopefully the piping upgrade will help the system work more efficiently when completed.
It was originally installed as a 2 pipe system way back when. Then when replaced, (however many years ago), the current home owner had sticker shock. So the system was down graded and not all pipes installed/used correctly, etc.
While I appreciate hearing this work May improve the system overall, my wife is not keen on the price tag. But if our heating bill goes down, she may change her mind. lol

Thanks for your insights.

yyou_stinka

@pecmsg when the boiler is operating the dial gauge barely moves, if at all. Still reads below 1psi, probably not even close to .75psi.

There have been some knuckleheads that worked on our system before we bought the place. So it’s hard to know (exactly), what tinkering may have been down needlessly in the past.

Long Beach Ed

You mention there was some repiping done to a "two pipe system" and now it's a "one pipe system". It's doubtful that this was done and if it was, it's even more doubtful that it was done correctly.

The problems you describe typically result from a poorly piped boiler.

If you post some photos of the pipes above the boiler,plenty of folks here can offer advice and assessment.

mattmia2

Make sure the person that re-pipes it knows what they are doing.

pecmsg

https://forum.heatinghelp.com/discussion/comment/1840005#Comment_1840005

Exactly why you need a 0 - 3 # gauge as well.

yyou_stinka

@Long Beach Ed As unlikely as it may seem, I have several caped return pipes and endless number of filled holes in my hardwood floors to prove it. Also confirmed, with one glance at my boiler by the former owner of the service company I use. No need to post photos. Some responses already have helped to paint a more cohesive perspective, as well as the “wet steam poll”. I am however, always on the hunt for suggestions for reliable air vent manufacturers? Regardless of the issues within my system, a vent should not fail within hours, while some last months or even a full season.

mattmia2

Quality air vents should last for decades on a properly functioning system.

Long Beach Ed

https://forum.heatinghelp.com/discussion/comment/1840277#Comment_1840277

I'm not inferring that anything you said isn't true. Two pipe systems require much smaller diameter piping, so if a two pipe system is converted to a one-pipe system, the piping will generally be too small, tremendously increasing steam velocity. The system wouldn't work properly. If this has been done, and pipe sizes are incorrect, you failing vents may be one symptom of the problems that modification caused.

And yes, if vents are mistreated, some can fail in hours while others hang on for months. There are many variables- with the vents and with different radiators and positions in the system.

You are speaking to many industry experts here who are selflessly trying to help you. They deserve your respect. Without some photos, it would be difficult to assess your current conditions. I do make my living designing this stuff.

pedmec

Exactly what @long beach Ed said. I couldn't agree more. You most likely have condensate slamming the air vents because they can't get past the incoming steam that is being supplied now with the undersized supply feeds. I doubt that the manufacturers are sending out bad vents. It's more like your system is the problem.