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heat control valve


captden29

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I am putting my heat system back together. the heat control valve has a capillary tube the goes thru the firewall into the cab area. I think it just goes anywhere out of sight. my question is what is it for? this is a 54 Chrysler Windsor.    capt den

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the heat or temp gage is what I think you are talking about. Yes there isa capilaary bulb and the end of the tube and this goes into a hole on the side of the head of your engine. The bulb goes into the hole that is threaded and then watet temp degress then increase or decress the fluid inthe bulb to register the engine temp.  Be very careful not to break the tube then all of the fluid inthe tube will be lost.

 

Rich HArtung

Desoto1939@aol.com

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thanks rich. there really is a capillary tube on the heat control valve. on my car the valve is located inside the engine compartment inside a cover on the firewall. the heater core is inside there.the heat control valve is also in there and the hoses from the engine all connect in here and of course you get hot air for the heater and defroster. the heat control valve has a capillary tube that connects to it and then goes through a hole in the fire wall to inside the car. it just goes in and gets tucked out of sight but does not connect to anything else. it must sense temperature, but then what effect does it have on the valve? just looking it over I am stumped as to its purpose and I have found no literature that mentions it. I may have to call old air products as I believe they rebuilt it years ago. I also had the heater core done a few years ago, and I am sending out the blower motor for a rebuild. I just retired so I have the time to do this now. my grandparents had a 39 desoto. I remember standing up in the back seat on the way to the beach.  thanks for the help,     capt den    

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I am not able to do pictures, but if you google heater control valve you will get pictures and the capillary tube is plainly visible. not sure why the valve needs the tube to sense temp and control the valve opening as the temp. control on the dash already does that. mystery.   capt den

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I believe the capillary tube senses temperature in the heated air duct and partially controls the heater valve to hold a constant air temperature, like a thermostat. So you set the desired temp with the hot/cold control and then the bulb tries to hold it there. I don't know how well it works as my car (50 New Yorker) had a replacement valve with no bulb. NOS ones are very pricey. I have heard there is a Volvo part with a bulb that can be adapted. I use my heater a lot this time of year in Canada and with just the hot/cold control it takes a lot of fiddling to get the temperature comfortable, so the bulb thermostat seems like a good idea.

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My 46-54 repair manual shows that a model 550 heater had the sensor attached to the cross body heater tube that was run side to side on the firewall. The picture appears to have some type of metal plate that held it to the Outside of that tube.  The picture in this book is very grainy and I feel would never be clear enough to be copied and posted here to be worhwhile  The written explanation (very sort) said what what was posted earlier that it was meant to help keep the temp. even without constant adjustments to the other controls.

Oh, well. My 50 Ply. that had this version and the tube was just pushed through a hole in the pass. side of that tube. The whole setup was leaking and the only one I ever saw for sale was on EBAY for $350 . Free shipped though!

Not for Me! I will do as many adjustments as needed!

 

Hope that helps somehow.

 

DJ

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The water flow control valve to the cab heater core opens and closes automatically I believe. The brass tube goes inside the heater duct. As it gets hot, it closes off the water valve. When its cool it opens the water valve more.. I believe its a temperature regulator.  Without the valve you have full flow, hot water, coming in all the time. It makes a lot of heat in the cab! Only way to control the heat temperature with no regulated valve, is by turning off the blower fan. Off and on as needed. Or opening The fresh air cowl vent to let cool air in. Not ideal. 
 

My original regulator valve was not working. I removed it and plumbed my cab heater system without the regulator valve. I have no thermostatic control any more in my ‘53. Off or on is all I get. Smokin hot or cold as ice these days. In the summer I close the water valve at the rear of the head, so no hot coolant gets to the heater core. 
 

If I recall the temp probe tube has ether inside it. As the ether heats it creates pressure.  This pressure opens and closes the heater control valve. 
 

I am not trying to win a Concourse show. The price to replace my damaged valve was too much. So I plumbed it out. We’re all happy to have heat again when needed. 
 

Original valve seen here. Bottom left 
 

Keith

 

 

52BA3974-1C19-4F2A-BC99-8F93386CA33C.jpeg

Edited by keithb7
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Thermostatic valve, the capillary has a fluid in it that will regulate the valve. Very similar to operation of a thermostatic expansion valve (TXV) in a/c.  I work with heavy trucks (parts side of things nowadays) and a lot of them use a valve similar in nature for the air conditioning, but they use two parts for the individual part shown there (capillary switch and separate water valve).

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Got this valve for my '50 Coronet. Works great. A little pricey, but not as expensive as some have said they found.

https://www.ebay.com/itm/Water-Heater-Control-Valve-1688946-fits-Dodge-Chrysler-Plymouth-DeSoto-1955-1956/112176543764?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Wes

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Looks like China is reproducing them now. Previously all I’ve seen on eBay were NOS ones. The repop is not cheap but its nice to have the option of buying a new one.

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I have the same setup on my 49 Windsor and I tried pulling it out recently because it started leaking coolant into the cab. I thought the copper wire coming off it was some sort of ground wire and even though I was trying to be careful with it, I ended up breaking it while pulling the valve out. What Keith said about that time having ether in it makes sense because oh boy did it smell awful when I broke it apart! I had found another site that claims to offer a rebuild service for the factory unit but the price is still pretty up there.

 

https://www.moparmall.com/MoPar-PN-1369742-Heater-Valve-p/816-288r.htm

 

It doesn't get brutally cold here in Colorado so I'm not too worried about having a fully functional control valve, and while I'd like to try and keep the operation of it as it was meant to be I have a hard time justifying spending $200+ on such a novel comfort item. I've seen other mentions in this forum of people adapting similar valves off of newer vehicles with decent results. Just haven't found the exact part that would work though.

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