Shewman's High Flow Thermostats

[Bluebell]

Old Henry, those first ones in post #62 are bellows type stats.
If I recall they are alcohol filled.(I cant remember for sure)
Anyhow this might be of interest;
The wax stats normally fail in the open position, (a good thing) and the bellows type usually fail in the closed position (bad)
I dont think anyone is making the bellows type commercially anymore.

[Old Henry]

Originally Posted by Bluebell

The wax stats normally fail in the open position, (a good thing) and the bellows type usually fail in the closed position (bad)

I've heard that but can't figure out how the wax ones can fail in the open position when they have that spring holding them shut. What would make the wax expand against the spring when it fails?

Curious.

[Bluebell]

I have never cut one of the pellets open, but I think the wax just leaks to the other side of a piston. Anyhow, I have removed a few over the years and that is how I found them. Stuck open.

[Old Henry]

Maybe it has something to do with the metals that they mix in with the wax that swell up when the wax is gone. Interesting.