M55 FS Vacuum Switch/Pressure Switch

[vinny11950]

So after mysteriously killing another Vacuum Switch, I set out to find the switch online for a cheaper price.

I couldn't even find the original model by Cleveland Controls: DFS 221-222.

After reading all the specs, I settled for DFS 221-112. Found it at Grainger for $29, including tax.

The only difference is that the DFS 221-222 model is only set up to work with negative pressure.

The DFS 221-112 model can work with positive, negative or both at the same time.

DFS 221-222 on the left, DFS 221-112 on the right.



More images of the old DFS 221-112 taken apart. I had to find out what went wrong. I could not. Probably because I tore up the diaphragm in the process. Notice the diaphragm hangs inside the unit and moves on the switch according to the pressure. Also notice this model only has one barbed connection point for the negative pressure hose.





Below is the new one I used, DFS 221-112. It has two barbed connection points for hoses and three electrical connections. I took off the Norm Closed electrical connection and taped it up. That is pretty much it. Leave the other barbed connection open - Do not tape it or block it in any way. It needs to be open




Back up again, a roaring fire, snowing outside (excuse the unfinished wall behind).


And a picture of my stash. Got lucky when I went to Lowes in November and bought 4 tons of pellets thinking I would leave most for next year. 3 tons of Somersets and 1 of Prestologs. This was with another 1.5 tons of mixed pellets I had already.

Well, with the colder weather in Eastern Long Island this year and my parents love of 76 degree and over inside temps, they have been burning about 2 bags a day. Still have plenty of pellets, but I will be lucky to have 2 tons for next winter.

The Somersets have been burning real clean and hot. 2 weeks since the last major cleaning and the ash bin was barely 1/3 full. The pellets put out a soft, white ash.

 

[Lake Girl]

How many have you gone through? Charring on the old one? Could be you're getting too much current from the board? Faulty connection in your wiring?

 

[Harvey Schneider]

How many have you gone through? Charring on the old one? Could be you're getting too much current from the board? Faulty connection in your wiring?

Good eyes, I missed that.
Most likely not enough contact pressure at the Faston. A gentle squeeze with a pair of pliers will correct that. Or you could just replace the Faston, they're cheap.
Another possibility is a stalled auger motor, but I think it much more likely that the Faston is weak.
The heat created by the loose connection cooks the switch internally. Your new one will fail if you don't fix the Faston.

Edit:
This one should work and is only $9:
http://www.allelectronics.com/make-a-store/item/PSW-15/PRESSURE-SWITCH/1.html

 

[vinny11950]

How many have you gone through? Charring on the old one? Could be you're getting too much current from the board? Faulty connection in your wiring?

Good catch, Lake Girl. I read somewhere else that the way the switch is glued to the body breaks down, so I added some high temp silicone that I had laying around. Didn't have the patience to try as I just installed the new one.

I will check the wiring and voltage. But this is second one I have replaced in two years.

 

[vinny11950]

Good eyes, I missed that.
Most likely not enough contact pressure at the Faston. A gentle squeeze with a pair of pliers will correct that. Or you could just replace the Faston, they're cheap.
Another possibility is a stalled auger motor, but I think it much more likely that the Faston is weak.
The heat created by the loose connection cooks the switch internally. Your new one will fail if you don't fix the Faston.

Edit:
This one should work and is only $9:
http://www.allelectronics.com/make-a-store/item/PSW-15/PRESSURE-SWITCH/1.html

Thanks, Harvey, had not thought of the Faston connection.

I was looking at other models but didn't want to deviate too much from the original. I will check them out, if just to have options.