Re: Heater Control Valves

Posted by HH56 On 2017/5/14 14:33:47

I know in 48-50 models they changed valve mfgs. Think the first were Eaton and believe they changed to Ranco. Believe there was a change in the capillary tube length and sensor bulb at that time. There was also a relocation of where the sensing bulb was mounted from the early 48s to the later cars. That position change is covered in a service article.

In 51-4 I vaguely remember reading of a change in the capillary sensing tube length or size which I believe was to make them more responsive. Don't remember where I read it to refer to the item to see if there were other changes. Since for 54 there was also a change in the heater distribution duct at the same time as a different valve there could be a change in the sensing tube location.

In 55-6 there was a definite change in sensing tube location. One valve was used with heater only and another if the car also had factory AC. The difference in those was the position of the body of the valve was rotated in relation to the hose connections and also the location of the capillary sensing tube on the body in order to accommodate the AC box and the revised position of the small air outlet which directed heated air over the capillary.

By 54 believe the heater was standard on all Packard models and maybe in previous years too. On Clippers it was optional but AFAIK, the units were the same item. I don't remember if the core was changed in 54 or if that waited until 55. I did the 54 Pacific and can't remember but think it was still like the older models.

On the 51-3 models for sure the core was positioned flat in the box with air coming up around the periphery and then redirected down thru the center of the core and into the car. It was kind of a choke point as far as airflow or volume. In 55 and maybe 54 the core was mounted on a slant and all air made one straight pass thru the core before entering the car.