Maid O' Mist No. 67 Auto-Vent

did job very well. a few zones on our boiler system were not getting the hot water pumped through it. the furnace had a gauge which read about 8 p.s.i. which said to me the plumbing runs at that pressure. I read you have to match the expansion tank to whatever pressure you are running. after shutting off the pumps and draining the water from the boiler plumbing then checking pressure to the expansion tank it read nothing. I filled first with 12 psi for a week or so because I read online that was standard. I let it run a week and no improvement on the circulation to the two zones. I opened up the very top of our old maid-o mist air vent and pushed down on the valve and it began leaking water. so it dripped and leaked slowly until ordering this replacement same exact part but a new one. When I got it I did the same thing turned off pums drained all water from the lowest point of the boiler system with a garden hose pumping out all the hot water outside, then took channel locks and squeezed the middle of the old maid o mist no 67 auto vent crushing it then turning it and got it out. put the new one in per instructions on box. when on box it said loosen it slightly they mean the very top cap and I saw why when it began working a bit later. Next I reduced the air pressure by pushing the needle of the shrader at the bottom of the expansion tank to 8 psi matching our house (boiler system) pressure. with the new no 67 auto vent installed I closed the drain valve disconnected garden hose, turned back on the pumps and valves to incoming hot waters and within a minute I began hearing this thing working to neutralize air pressure. we had to turn off a few zone valves to have hot water again for some reason because we had also just replaced one of our pumps but it was a smaller pump than we should have. once this worked, we were able to get hot water on every zone including the apprx. 500 ft of radiant floor heating zone that I had installed last fall to heat the kitchen, family room, and two other rooms. now all has been good. this little guy did quite a bit for the 7 bux and now nothing is leaking where the boiler is. We have an outdoor wood boiler that we use to heat house and hot water during the cold months and switch to propane to just heat the hot water when its warm outside. I do plan to next cut out a section of our copper pipe during the off season which is all corroded and has a lot of white scale all around it because i fear its pinching our water pressure from the inside thus reducing our flow and pressure. but all has been good since. incredibly pleased with this little piece. I noticed its popular this vent no. 67 although its available in other numbers this one also exists on my grandmothers brand new furnace she just got set up this yr by the professionals at wesco when she switched propane because they gave her half the price of the other company she had for propane, they found severe problems with her old one. this no. 67 auto vent I noticed also exists on her setup.

I ordered 5 of the 67 Auto-Vents and 10 AS-9 shut-off valves. I already had 5 of the Auto-Vents from a local plumbing shop, which costed me 4X as much each as these. I have a 3-zone heating system and a 2-story house. All 5 Auto-Vents came in new boxes, but 2 had been used before; their stems were crusty and the metal was discolored. I tried to use them. One still worked, but the other leaked badly. Fortunately, I had first installed the AS-9 valves, and was able to unscrew the unit before it made a mess of my downstairs ceiling. I sent the vendor an email complaining, but received no response. I've scanned the other reviews for this product, and see no similar complaints. So, I'm just guessing that someone returned the used units for a refund, probably by accident, or maybe intentionally, and someone didn't check the boxes to verify that they were good. I spend more than $4,000 a year heating my home. These units are a pittance in comparison, not worth very much complaining. I also see complaints that these units are not as good as the original ones on a system. But, as our systems age, mineral deposits collect inside, break loose and jam-up these kinds of units. So, I would not expect them to last as long as the original ones. Lastly, do be sure to also install the AS-9 check valves, if you don't already have them. They make future change-outs easy, with no need to depressurize and partly drain the system. And you may also need to get some 1/8 inch connectors at your local box store in order to install them depending upon how the old fittings were installed or how they come apart. These only cost about $2. each.

First valve delivered was used. Replacement was ok but not clean looking like pictureAlso picture shows the box ,valve and shut off fitting.You get the box and valve. Fitting has to be ordered separately. Fooled me.Why show something that's not included. Read description carefully

A nice product with a reasonable price .

It appears to be used, has rust on it, and pitted, and when I put it on it was leaking so I had to tighten the cap so it doesn’t leak.

Worked well to replace identical valve

This is a great product that many heating (and cooling?) systems need. I wish I had realized that mine needed replacement a little more quickly. I should have guessed when I saw water solids on the outside of it. After trying a bunch of things to get the air out of my hot water heating system I decided that I'd try a new float vent. Turns out ... that was the problem. It works great. I'll get a spare to keep around.

The price is good, but the picture showing the auto shutoff is deceptive since it's not included, the seller world be better to charge extra to include the auto shutoff as a package than to show it but not ship it.