Identify That Part! - Penn Controls P72LE

[Depewtee]

Hi All -

As I continue to go through my bus and learn the various systems I keep coming across parts that I have no idea what they do.  Today's version of "Identify That Part" includes the item pictured below.  I actually have more information about this part than most I have found on the bus.  It has an identification tag on it that reads "Penn Automatic Controller, Type P72LE, Model 1, Range 20" 100#."  A quick Internet search revealed that Penn Controls is now owned by Johnson Controls.  Looking at the fittings (and the fact that Johnson owns Penn) I am thinking it may be some kind of A/C controller??  It was located near the upper hinge of the curbside engine bay door on my 1981 Prevost.  Looks like it has been disconnected for years - nothing hooked to the fittings and the two wires were snipped off.  It looks a little rough on the outside, but looks really good on the inside.









Brian S.

[James77MCI8]

Looks like the unloader control for the Air Conditioning compressor.

[Depewtee]

There is a switch on my dash that reads "A/C Clutch" and "On/Off."  I will investigate it further, but I have yet to notice it doing anything.  Also, I have a Cruise Air unit that looks like it works off of an automotive belt-driven style compressor.

Brian S.

[Nick Badame Refrig/ACC]

Hi Brian,

What you have is a mechanical, duel pressure control for your OTR A/C refrigerant system.

The left side controls low side cut in and cut differentials. [cut in 35#, cut out 5#] sounds like an R-12 system..

The right side controls high pressure cut out. [safty] [300# head]

This control cycles your compressor on and off as needed for cooling as second in line from your master switch.

Yes, Penn/Johnson controls merged together about 10-12 years ago.

Here is a PDF to the P70 control that would replace your Penn control.
http://www.shancontrols.com/PDF/P70%20Series%20Dual%20Pressure%20Control.pdf

Here is one in the Ranco Controls version also.
http://www.rsl.ca/CAT2009/page564.pdf

Good Luck
Nick-

[Depewtee]

Nick,

Thanks for the reply and the detailed information.  Like many things on my bus, I believe an PO has removed one system and replaced it with another (or at least part of it).  Here is a picture of my current compressor...



The reason I think the system is a replacement is the location of the A/C controls has always puzzled me.  The controls are located in a little nook just behind the driver's seat.  Although the driver can adjust the controls, it is difficult and cannot be done while in motion.  The location is such that it is nearly impossible for a passenger to access the controls.  Another thing that has puzzled me is there are two "spare" sets of controls in one of the bays (they are just in a box, look used, and I do not know if they work).  The controls say CruisAir on them (notice no "e").  The system seems to work, but not sure how practical it is with the three roof airs (definitely added after the fact).  The CruisAir requires 110V to operate, so I need the generator running for air (might as well use the roof airs at that point).  The CruisAir blower is located directly above the driver and has no ductwork - it just blows straight down.  Anybody seen one of these systems before?  Do you think it is original from the converter (Liberty Coach)?



I currently have the front of the cabinet pulled off while I work on some other issues in that area.


Brian S.

[Nick Badame Refrig/ACC]

Hi Brian,

Your cruisaire control is deff from the early 80's.... Most converters back then used cruisair and Liberty did too.

However, Liberty usually installed 2-3 cruisair systems in their coaches. Maybe the PO removed a system or two

because they are quite expancive to replace. [about 3 times+ the cost of roof air's] You could have spare parts!!

Good Luck
Nick-

[Depewtee]

Liberty usually installed 2-3 cruisair systems in their coaches. Maybe the PO removed a system or two

because they are quite expancive to replace. [about 3 times+ the cost of roof air's] You could have spare parts!!

Nick,

That would explain the two spare control panels....  It also might explain why the cabinet above the refrigerator and the one above the bed are different.  I bet the two additional blower units were located in them - they seem to be the right size.  Possibly another mystery solved....

I would like to have air for the driver while going down the road and without having to run the generator.  I already have the compressor (and it seems to be working), has anyone had luck installing a modified automotive A/C?

Brian S.

[Nick Badame Refrig/ACC]

Hi Brian,

Look behind the spare tire compartment. [behind the front bumper] They sometimes crammed in 3 condencers

in that small space...    Look for cut off copper lines.

Nick-

[Depewtee]

I was modifying my last post as Nick was replying.  I am good to look around some more and take some pictures.

Brian S.

[Depewtee]

Liberty usually installed 2-3 cruisair systems in their coaches. Maybe the PO removed a system or two

because they are quite expancive to replace. [about 3 times+ the cost of roof air's] You could have spare parts!!

Good Luck
Nick-

Look behind the spare tire compartment. [behind the front bumper] They sometimes crammed in 3 condencers

in that small space...    Look for cut off copper lines.

Nick is officially "Da' Man" when it comes to HVAC systems!  I did some snooping around my bus this morning and Just like Nick said, I found two condensors in the spare tire area.



Additionally, I always wondered what was originally in this space... condensor number three!



If you look closely at the picture above you can see where the vent through the floor has been blocked off.  Also, if you look real close you can see the "footprint" of the condensor in the floor (this footprint has the same dimensions as the two condensors in the spare tire area).  What you cannot see in the pictures is the cutoff copper lines (another good call Nick!).

I tore out the cabinet that contained the middle CruisAir, but it looked just like the rear cabinet pictured below.  As you can see, at some point somebody covered the vent in the front of the cabinet with a mirror.  The vent in the bottom of the cabinet was covered over, but I removed the cover in the process of doing other demolition.





Not anytime soon, but I would like to replace the front 110V CruisAir with a 12V or 24V system for "down the road" A/C for the driver (me!).  Anybody have a need for old CruisAir pieces and parts?  

Brian S.

[Nick Badame Refrig/ACC]

 

[jmblake]

Depewtee
That little box you had in your hand is a pricey little box, I just replaced mine last summer and the new one from MCI was around $250.00 so don't just through it away it maybe worth something. Always need extra $ for the bus. Jason

[Depewtee]

I learned my lesson early... I was tossing out way too much stuff I was removing from the bus.  I am finding out some of those things are scarce and might be used by others.  I have now started a "junk box" for the stuff I take off the bus. 

Brian S.

[robertglines1]

he 89 and 98 both had the auxiliary air (drivers air) ac system the compressor clutch is 24 volt on both. If you get a auto type you might have to convert clutch to 12 volt feed.When you get ready pm me.  The unit from prevost for auxiliary air are 2 ton.  Bob