Packard Forum Index » Project Blogs

A poster asked for a wiring diagram of the factory AC unit. Here it is and this one also shows the added cable operated thermostat I installed in my build to control the new Sanden compressor clutch. The thermostat was added in the green wire feeding the clutch.

Attach file:

---

  (117.54 KB)

Howard, does the thermostat make it act as a quasi climate control and do you suppose that something like that could be added to the blower to turn the fan speed down and even off when not needed?

This thermostat is just the typical on/off switch that controls the compressor clutch as used in a basic hang on unit -- and what most factory systems went to after the gas crisis in order to improve efficiency numbers. When the evaporator reaches the set temp or gets to the point there might be water freezing on the fins it turns the compressor off and when the evaporator warms up again it turns it back on. It has an advertised evaporator adjustment range of about 33-60 degrees.

The 55-6 Packard system had the compressor running all the time AC was turned on. The modulator valve controlled the temp and was fixed at around 40 degrees. When that temp was reached it opened to allow most of the refrigerant to bypass the evaporator and short circuit back to the compressor to essentially starve the evaporator and slow the cooling. As the evaporator warmed up the valve closed and forced the refrigerant to flow thru the evaporator again.

There are advantages and disadvantages to both methods but at the moment my vote for disadvantage prize goes to the Packard system because modulator valves that will fit seem to be all but extinct and mine is kaput.

Howard:
Noting that this thread started some years ago, under the heading of "had I known then what I know now"; do you still recommend the 16x22 condenser from Nostalgic Air that you so nicely modified to fit in message #16. I am looking to replicate your solution. If the dimensions of the mounting bracket still exist I would be very interested.
You do nice work.
Thanks
Dave
1955 400

Will be honest that I have not driven the car much but do start it up occasionally and the AC still works with the car sitting in the garage so I don't think of anything I would change at the moment. Not sure if the exact condenser is still available but if so then here are the dimensions of the brackets. You will need to get the mounting hole spacing from your car and from the condenser you use but the rest should be about the same.

One thing I notice that I did not include on the schematic was that a binary switch was also used as an additional safety for the compressor. It is simply a switch mounted in the refrigerant line that senses low or high pressure and cuts the compressor off if pressures go out of spec. Mine is in an additional port on the filter drier but they can be placed directly in the high pressure line with a special fitting. Electrically the switch is in series with the thermostat so the power to the clutch is cut if a problem develops.

Here are photos of the bracket and more of the condenser and drier installation.

Attach file:

---

  (95.95 KB)


  (162.64 KB)


  (145.33 KB)


  (148.81 KB)

Thanks for the prompt reply - right on the money. I appreciate the extra photos which are very helpful. I mounted the compressor on the right side of the engine. I assume that I can just turn the condenser 180 degrees on the vertical axis to have the plumbing come out on the passenger (right) side of the car (but reversing the airflow through the condenser).
I'll be installing an underdash unit, hopefully simplifying my update.
Thanks for the help.

Howard:
I have another question for you. I purchase the condenser called out in your article, 16x22 from Nostalgic Air. My 16x22 seems to be a bit bigger than the one have pictured. It appears the 16x20 may fit better. If I was correct in my attempt in reverse Engineering your design (which I should complement you on, a nice implementation of new technology into the classic form); it appears you kicked the positioning of the condenser over about 2 inches and slightly up, to allow access for the Freon connections which can interfere with the horn locations.

The unit I have is just about the same width (approx. 23") as the original condenser and does not permit the convenience of a shift. I'm looking to exchange for a 16x20 (part no. 54-1620) unit to give me some working space. Can I ask you what considerations you made in positioning the condenser both to the right and slightly up? Everything appears to fit nicely.

Fortunately I have access to another 55, with air, where I have been able to make measurement. I'll attempt to attach a picture showing my 16x22 next to the original condenser.
Once again thanks for your help.

Dave

Attach file:

---

  (206.03 KB)

As you can tell from the width of the brackets and a slight additional bend on the vertical portion of the larger one the condenser is slightly to the right of center to give a bit of room for the fittings but nothing special other than that. Looking closely if doing it again I would have moved it to the right another 1/8" or so because the hose just barely clears the horn on the left.

Here is the measurements I have from the approximate center of the round condenser manifold tube to the edge of the fender flange just below the top hole. My fenders measure 40 1/2 from flange edge to flange edge with the condenser positioned slightly offset as shown. Am assuming you are reversing your condenser to have the connections on the right to better reach your compressor but that should not make too much difference.

Attach file:

---

  (125.28 KB)


  (153.53 KB)

Is this a factory condenser? If I asked this elsewhere my apologies but I need to be sure.

Note: uploading the photos seemed to have caused an odd Moir? pattern to appear but it's not on the actual part.

Attach file:

---

  (479.80 KB)


  (488.67 KB)


  (332.70 KB)

It appears to be a factory 55-6 condenser. Here is a photo of what I had in my car and a factory photo showing tubing connections in a 55.

Attach file:

---

  (108.84 KB)


  (213.79 KB)