Hi art, want to chat some more, eh!

I will have to think more about making time to look at those old valves.
I admit there has not been a lot of motivation over the years to tinker with them.

My climate is very temperate for me and I can just leave the set where ever it was last. I can be anywhere in town in ten minutes. I can leave it half way and the time I travel a mile the engine is up to temperature.

Your point of air blending doors is well taken as I use the recirculate button or I open a window if its not raining. I live most year around in sweat shirts or a medium heavy jacket in our worse winter.
Consequently, the valve is not high on a priority list. I may have mentioned some of that in other postings in the far back past.

In the near future, I again will be away from home and at my sister-in laws home. I will be the care taker of four dogs and fix it man for a widow woman. This is in Southern California of which is not my favorite place to be!

My wife is setting up an USA nonprofit information organization with roots connected to a nonprofit located in the UK.
The wife and her sister travel here in the US and to Europe while going to medical conferences that is gaining recognition and her time.
I did enough traveling in my younger days and with all the travel hassles I just as soon let them go!
By the time they get done, with the first half of this years running around, it be coming closer to summer and that's when I want to stay home and be cooler.

So that is things go with married life and right after that, I have made less promises!

It is interesting that you mentioned industrial hydronic systems. I do, think like that, so you nailed me!
Europe uses that type of system quite a bit. They have better and tougher regulations in making their products. They are refined into simplicity. The Danfoss Company is quite popular to being as big as Ranco or crossed in with Honeywell. They are very compact valve units.

Danfoss started in the early forties and they may have invented the wax motor but I am not total sure of that. They have changed over to gas powered units by around the early nineties due to energy cry babies just like we have here.

Dave mention that Ranco could have used wax in this valve.

This is always a possibility but to my knowledge the wax motor is about thirty percent slower in response time than the refrigerant gas filled bellows that we have talked about. To my knowledge Ranco thermostats started out using the gas or Mercury in oven stats as the temperature of ovens exceed the operational range of gases.

So, i can only surmise at the time a group Volvo engineers picked up a Ranco reference book. It offered things better than they could get from European vendors. I have no proof what so ever, just a guess on my part as I have done it myself while shoving ideas around a table.

For those who are following us, its called R&D or research and development collaboration.
I had to make what they could just draw with a pencil and sometimes there has to be concessions considered in prototyping versus production schemes.
I am sure Dave has seen some of that arena!

Now that I got that out there I will add that EPA is probably eyeballing Ranco processes as much as the fluorescent bulbs going green. The push towards more LED's or electronic controls are forever on the move.

When we talk automotive, Dephi (a major automotive parts supplier) is now pushing brushless pumps for in-tank uses. They recognize the brush pumps faults but in reading they are highlighting its efficiency most.
I read some of their papers (about a year ago) and there is a gain of about two percent reduction of power usage or more if their design can vary the output as needed. Good talk, but they are taking DOE money for doing the research so it might be buzz words in there for them.
That paper would be right up your alley Art. The motor use a Nine pole versus Ten pole rotors and stators combination with a three phase motors likeness and using one coil as a EMF feedback circuit. Sounds like AC and DC tweaking for me, all at the same time.

I have noticed a push towards brushless in power tools and of course the price difference, guess where the fuel pumps are going. It's just progress, even if its two percent here and thirty percent from the wallet, dam the torpedoes, anyway!

So to end this up for Dave's interest the idea of a manual valve is the best and simplest for all on the brickboard as you said Art.

The ideas I have had are not researched out.

One could use the compact Danfoss angle valve with variable and lockable setting down there "AT" the valve. Nipples would have to be located or made in my case. It is "A"set it and forget it until summer time package, then, dial it back for A/C use. Or use a remote cap tube control and set it that way. Of course, as Dave said, for more bucks.

The other method would be use a 12 volt solenoid valve with a standard Ranco C12 cap tube thermostat w/ a 60 to 98 degree range.
Or a electronic thermostat with digital accuracy but I would for go the setback features! (:)

Again,I have not done the research or pricing but I think if one shopped well all may fall in Dave's price range.
Any gains to be worth "A" difference would be left up to the enthusiast to weigh out.
Throttling a valve, goes back as far as putting rocks in a stream and it works!

I know how enthused I would be and it took a man like Dave, to jump in there. He is the man too!
He said it fell that way like the seat cushions.

I watch to see if he goes for both halves. I think he is near Bakersfield? I could save shipping by hanging at my sister-in-laws too long!

Oh! Did I digress again....it's Ok, I was just doing my IMHO chit chat, as always! This is one nuisance that goes away like a T.V.......click!
Phil