Looking for an air vent that doesn't leak

Sissy

From what I've seen no manufacturer of "vent cans", makes a satisfactory vent. Spirovent to me, is the best system vent available assuming no contaminants are present to gum up the float.

Jeremy_14

Air Vents

Why do seemingly all air vents on hot water heating systems leak. I'm ok with a cheap 1/8" vent leaking year to year, but even the mid grade to expensive vents often leak, many times just after I've installed them. I don't want to have to use a half inch black cap to plug the top of a new hundred dollar leaking air vent.

Are there any air vents made that can be left open, and be counted on for atleast 5 years of reliability most of the time?

billtwocase

jeremy

I personally haven't seen those days since the old brass Maid O Mist. I use Taco 400, and they hold up pretty well, and do actually allow air out. I've tried some of the exspensive inlines, but when they leak, too much to replace. good luck. peace

hot_rod

look for a brand

that offers hydroscopic vent caps.

This cap has a series of disc that swell and shut off in 2-3 seconds after fluid hits them.

At some point the system should be air free and the valve should be seated and leak free. but the reality is...

Another possibility is a system where the pump and expansion tank relationship is wrong, pumping towards the point of no pressure change . When the circ starts it can actually "inhale" a burst of air. This is usually found on systems with high head circs.

One manufacturer offers an "anti vacuum" cap to prevent that from happening. Basically a small check that fits below the vent cap to let air out, but never in. It's a real problem fixer.

Notice this "high head, pumping towards", arrangement on some of the early copper tube boilers, small diameter radiant tube installs. Installers that hadn't yet learned about PONPC. Myself included

hr

Tim Weaver

If you don't got the $$$ for a 1/2" Spirotop, try a Watts Auto-air vent.

Henry

SpiroVent is the ONLY reliable vent. We have had others that had burst at 50% of their pressure rating nevermind all the leaky ones!

hot_rod

no question that

water, or fluid quality is the key to all vents, regardless of the brand. Aggressive fluid can cause the steel or ss media in many brands to "un-ravel". these pieces then make their way into valves, pumps, manifolds, vents, etc.

Overheated glycol, low ph fluids, are particulary hard on those metallic mesh medias.

Look for a purge, air or dirt, with a composite media to eliminate that potential.

If you have had issues with every brand of air removal, then it is probably system related issue, not the brand of device.

STILL, you need to keep the fluid in the system up to par. A good dirt removal system is another great option. If you can't, or don't get all the debris out of a system, which is very hard to do in old iron radiator and pipe systems, then a dirt removal device saves vents and system components.

Ideally a dirt remover, and a quality air vent should be installed.

The move is on to dirt removal devices, and away from Y strainers. A y-strainer traps and holds the debris in the fluid stream. A dirt removal device catches the debris and allows it to fall into a bottom chamber not limiting flow. Some will remove particles smaller than the diameter of a human hair.

These devices do take multiple passes to work, not all debris is trapped on the first trip through. Various manufacturers now offer dirt removal devices.

hr

Big Ed_4

Float vent tip

Tighten the cap down until it bottoms closed. Then just lossen just a crack. This will help prevent dirt from lodging under the valve seat by letting out the air very slowly. Venting too fast and the water rushes up the vent.

I cut open one of the maids o mist valves. Seems like there where two valves. One connected to the float and then the streider valve that only opened if the cap tighten down on the pin of the streider ?? Taco had the same set up but it seems they recently dropped the two valve design ..

Matthew Grallert

I love that you always come up with the relevent pictures and graphs for the tread HR. very cool.
Peace

Jeremy_14

Air vents

Thanks to all who responded, I'll try using the air vents you recommended. Especially thanks to Mad Dog, I had never heard of a dirt collector. I've used y-strainers to protect new gas mod con installs, but a dirt collector would help prevent limited heat service calls from a plugged strainer, and protect air vents. Great info.

Unknown

Dirt collectors,

are a great addition to any system,, but they can be costly!
I install mod/cons too, and I use the Taco 4900 series on the system side, then install one of these at the boiler.
Seldom a prob & easy to service, provided you flush the system first.

Dave