Emerson770 1 Dual Purpose SPDT Air Switch

The first unit I received measured about 350 ohms between the common and normally closed contacts. (Should read less than 1 ohm) when activated I could hear the snap action of the switch but the common to normally open contact read as an open (Should read less than 1 ohm). I returned and amazon sent another unit which I received today. I grabbed my meter and measured the normally closed contact and it read as an open (Should read less than 1 ohm) , I active the switch and the normally open contacts read .2 ohms. Luckily I only need the contacts to make when the switch is activated so I'm going to keep this one but it is still junk. Apparently china has no quality control. Anyone know if any one in the states makes one of these? The box says WHITE RODGERS DIVISION Emerson Electric company St. Louis Mo. MADE IN CHINABefore any one piles on yes I had it in a vertical position.Not that anyone cares but I have 40 years experience as an electronics technician, I'm certain the product was at fault.I was afraid of this unit but the other reviews seemed to indicate it was a good unit so beware. I'm going to start looking for a QUALITY replacement because I doubt this will last a year.

Installed and tested, the normally open side of the switch works as advertised. Thumbs up. However, I tested the normally closed side of it - and did not detect any function. Not closed like it should have been and no change when I turned on the furnace blower. Therefore I deducted one star. Glad it works for me though. As for price, I very likely would have paid out more when you factor in gas money to go find one of these in a major city.

It comes with everything you need and you have options on its use to fit your needs and installation location. I have a new furnace and needed to connect a very old transformer so that it was only on when the blower kicked on. I have it installed on the cold air return and using negative pressure. It now works great to power and allows water to the humidifier only when the blower is running!

I used this for my humidifier. After I figured it out the product does work but there are really no instructions, and THE TEMPLATE IS WRONG. The measurements on the template for the distance of the pressure tube are too close. The tube will kink. I don't know how anyone would design this template, if they ever installed the device. After I drilled another hole about two inches below the original, it worked.

If you follow the directions exactly, and get enough pressure or negative pressure, it works great. I hooked it up to the whole house humidifier and finally am not wasting any water . The only reason I am giving it a 4 is that I had to go buy longer tubing (was inexpensive but a minor hassle).

Product works as described. Easy to install. Wiring to the control was a bit difficult as there are "guides" in the area where the screws are located. Did not need to adjust pressure/vacuum settings. Controls my humidifier.

This is a very good air switch. I now prefer it over a Sail Switch. Easy to install & none of the problems of a sail switch.

This differential pressure switch works very well and it is very sensitive.Very well built and practical.

Used as a proving safety switch for a steam humidifier. Works perfect.