Shewman's High Flow Thermostats

[Old Henry]

Originally Posted by VeryTangled

Hi Everyone,

I found a "how it's made" type video on thermostats on Youtube. I learned some about the wax and how the melting wax causes the opening and how the spring causes the closing.

https://www.youtube.com/watch?v=xVPtIi6sVYg

-VT/JeffH

Very good. I was wondering how they could sell what seems to be a complicated piece of machinery for $10.00. Cheap labor (machines).

That is also how Ford made the original thermostat for the 59A pressurized cooling system. (Pictures in Post # 44) However, Ford also made one differently for the non-pressurized systems - the 11A-8575-C. It used something else in the bellows that built up pressure under heat to open the valve and counted on a fixed pressure from the outside of the bellows to expand against, which it would not have had with a pressurized system.



Just out of interest, here are a couple more vintage stats.

The Dole adjustable stat that uses a bimetal strip to open and close.


And Fulton stats that work on the same principle as Ford's for non-pressurized systems:


(Pictures courtesy of my barn friend that sold me his NOS 78-8575-C's. Hope he doesn't mind.)

[ken ct]

Originally Posted by Old Henry

Very good. I was wondering how they could sell what seems to be a complicated piece of machinery for $10.00. Cheap labor (machines).

That is also how Ford made the original thermostat for the 59A pressurized cooling system. (Pictures in Post # 44) However, Ford also made one differently for the non-pressurized systems - the 11A-8575-C. It used something else in the bellows that built up pressure under heat to open the valve and counted on a fixed pressure from the outside of the bellows to expand against, which it would not have had with a pressurized system.



Just out of interest, here are a couple more vintage stats.

The Dole adjustable stat that uses a bimetal strip to open and close.


And Fulton stats that work on the same principle as Ford's for non-pressurized systems:


(Pictures courtesy of my barn friend that sold me his NOS 78-8575-C's. Hope he doesn't mind.)

I have a pr of 175 like in that last pic you show in my 36 and have another spare pr. And a pr of the ones with the big coiled flat spring near the bottom. ken ct.

[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]

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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.