Taco 400-4 1/8-Inch-NPT Float Air Hy-Vent

Feb 2017 update: Its 2017, but I noticed that I havent had a leaking Hy-Vent since I installed a heat pump hot water heater in 2015. This means the hydronic system never fires up to provide domestic hot water during the non-heating seasons. Whereas the oil furnace used to run daily to make hot water for laundry/showers/dishes, now it only runs September to April/May for baseboard heating. I should expect the Hy-Vents to double their service life from 3 years to 6 years. Original review: I would have given it 3.5 stars if possible. It does a great job of purging air from my hydronic/baseboard heating system zones. However, I have been marking dates on them since we remodeled our house 4 years ago, and none of them are older than 3 years. The culprit is always leaking water from the top cap, and I always find that the o-ring has been deformed permanently from just 2-3 years of use (see photos of failed vent valves that Im replacing with new ones I just purchased from Amazon). I would have given it 5 stars if Taco would sell a 3-pack or 5-pack of o-rings for say $2 so I dont have to toss an entire vent when only the o-ring fails. I expect these new ones to not last past 2017. Replacing these vents at the zones is fairly straightforward with only minor water spills and leaks to collect since I have a pair of shutoff valves at each zone. The one on top of the expansion tank is the most challenging since a lot of water comes out of the tank; Im going to use another reviewers advice and install a shutoff valve the next time the expansion tank vent fails.

I ordered this air vent to replace our old Maid-O-Mist vent, which has started to leak water and was heavily covered by mineral deposits. The product arrived exactly as shown on photo, its build quality is excellent, well worth its price and should last many, many more years.

From the time I installed this on a water softener system it constantly sticks. If I forget to go into the pump room and tap it every few days I get air in the water lines. It works fine once I tap on it but it doesnt want to open on its own. Its almost the exact same design as the one it replaced, and the old one never had a problem until the plastic parts just got brittle from age and broke. I suspect most designs are similar but Im trying another brand.

Great Amazoner Thank You A++++

TACO products are always well built

Im buying this for the second time in 5 years - to replace the original which lasted over 20 years. Same brand / same part number, but no longer made in the USA, hence the much shorter life.

Perfect replacement

Easy-Peasey to swap out my crusty calcified hi-hats for these new ones and these work perfectly. I leave the caps unscrewed slightly all the time to let them vent automatically. (Some people temporarily open them but generally keep them closed.). They release any air in the pipes and do not leak any water, after the air has been puged. I had replaced very similar ones that were about >10 years old and had a calcium build up in and around the vent valve. The build up was causing then to drizzle out water continuously. After installing a couple new ones, I unscrewed the caps on the old ones and soaked the whole things in a container of white vinegar for a couple weeks. The old ones are nearly like new again. I tested one of the cleaned up older ones and it has been working perfectly for a couple weeks now. I now have a couple spares.

Stopped the splashing of hot water through the previous air vent (open pipe) on an atmospheric pressure, gravity fed solar water heating system. Hope it lasts for many years to come.

Very high quality. Easy to install. Huge difference comparing to the old fashion air vents. My appliance is very low pressure (12 psi - water-based home heating system), and air vents often do not work, but this one does the job perfectly.