Watts 0590715 1/8" FV-4M1 Automatic Float Vent

I purchased this as a replacement to a 10 year old "snifter" style float vent that was beginning a slow weeping leak. The new valve is much more solid and it has required absolutely no attention beyond the initial loosening of the vent cap as prescribed by the installation instructions. I used a Teflon based pipe thread paste on the male threads, being careful not to get any near the opening. No leaks and what's really wonderful, my hot water system has vented itself so that it is almost completely silent when the heat comes up. It usually surprises me when established designs get a working update that is beyond cosmetic and this is one of those times. I was so pleased with the purchase I replaced another snifter at the far end of the system with another one of these.

Before I bought this, I could not get the air out of my hydronic baseboard system. I would hear gurggling when the heat ran and it ran for long periods of time with the baseboard units not getting very hot. Added this air vent and immediately heard it venting the air until the pipes filled with water. Just turn the top know open 2 turns. Also, needed to empty the system of water for a repair and the unit acts as a vacuum breaker allowing air to enter the system when water is not at the valve. Best part is it’s a solid piece of plumbing and it’s small enough to fit inside my baseboard covers.

I saw a couple of reviews that folks were using this to vent their pool pumps. I installed it in line with my pool pressure gauge and it works great. When I turn on the pump it hisses out the air and then shuts off automatically. I left the manual air release in place too, in case I need it. I double checked and there was no air left in the filter vessel. So much more convenient than a manual release and WAY cheaper than the plastomatic ARV valves we use at work ($300+), for the price of one of those I can buy 20 of these!

Old valve was full of sediment. This was a direct replacement and works as specified.

Exactly what they are described as

I did not install it yet, but it is the identical vent that has been on my boiler for many, many years, which I just found out that the threads on the plastic manual bleed at the top have stripped. The old valve is still fine, and I could just put the plastic screw from tis on onto the old unit, but for good measure, I will replace the unit. Having had the old unit on my boiler for so many reliable years, and this one being of identical construction by the same manufacturer, I give this a 5 star rating from experience.

What I got still works fine, possibly even an improvement over the under 7yr taco float vent that it replaced. Time will tell. What I received was a watts FV-4M1, which looks like a Watts Fv-4-1/4 (just copy 'n paste item description in amazon searchbar and you'll find it). The piece I got is 1/8" so it fit and functioned fine, but still, poor execution on this order.

I put this on my highest elevation radiator. It didn't solve my problem(gurgling when the pump ran). My real problem was the water intake pipe, which was clogged with rust. I fixed that and had to refill the system. As it was filling the auto vent hissed nicely as it bled off the air in the system. A few more burps when the pump came on. Now the system runs perfectly quiet and I didn't have to manually bleed the system. As a side note, I believe the plastic screw on top has two positions: Loose is for auto vent, tight is for when it starts leaking with age or to prevent the possibility of leaking when you don't need it to vent. I have a single loop system so one of these is probably enough. If you have multiple zones you might want one between the boiler and the pump and possibly one in each zone on a radiator. Anyway, I am very happy with this product. It makes dealing with a hydronic system much easier. Be aware that as these age they may leak and cause water damage in your house. This is a good web site for hydronic system maintenance: http://www.ronstultz.com/knowledge/Documents/Hydronic%20Heating%20System/Hydronic%20Heating%20System%20-%20All%20Things%20Related.htm