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

Hand tight for everything. Tighten the top cap, then back off quarter turn...BING yourfinish. Try running your circulation pump on highest setting for 15 to 30 minutes. You will hear the air coming out of the system.

exact replacement - works fine

Excellent quality, same as original on my furnace. Very good price. Be very careful when rplacing yourself, make sure water pressure is released & no HOT water in furnace or you will get burned.

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.

Seems to be a good Vent for my boiler and still working today !

Works as expected

Worked well

These have work perfectly on 3 of my upstairs radiators. I no longer have to bled air for the radiators when I dont feel heat. It was so annoying doing this manually so I decided to do some research and found out about these. Before you can install these, you will need to have your furnace drained so there will be no water pressure when you install these or you will have a flood if you try to install these. Your best bet will to have someone com out and install for you unless you have had experience draining your furnace. I was skeptical at first in buying these but now I wish I would have gotten one for each of my 5 upstairs radiators. Next year, I will definitely buy more of these for all my radiators.

works as it should. Had to change ex tank and auto fill valve and in a short time air was out of system

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.