Fan over the cab? 1973 Chieftan

[Hisroth]

Hello all,


New to the forum.  Just sold our sandpiper travel trailer and bought a 73 Chieftan to build some family memories with.


Spending this first year just going through the thing and trying to get it all roadworthy.


Have completely redone the inside, new AC, new water lines (will put in new holding tank later have bypassed for now), new tires, new vents, etc...


Having the brake cylinders rebuilt at the moment because it doesn't appear parts for these are available anymore?


Anyway, my main question is, what is the condenser/radiator looking thing over the cab?  I don't see any vents inside that correspond with it, and don't have any idea what it is or what it does.  It's on the roof and there's nothing inside to give me any clue what it is.


Would attach a picture, but it's off at the shop right now with the brake issue.

[stanDman111]

condenser for in dash a/c , I think,=some condenser's where mounted on the roof in stead of in front of the rad

[Hisroth]

condenser for in dash a/c , I think,=some condenser's where mounted on the roof in stead of in front of the rad

That makes sense, but there's no AC option anywhere on the dash that I can find, which is why I wasn't sure if that was it or not.


All I can find is "Fan" and "Heat" and "Defrost" options.


Could very likely still be it and it only works on defrost setting?

[stanDman111]

maybe a pic of the unit or of the control panel might help to identify it ?

[Hisroth]

Good idea.


Will post one when I get it back from the shop, hopefully this week.

[RCND]

Hello All:


I thought I would revive this old thread for those that may be interested.


My wife and I just purchased a 1973 superior MH. It has the over cab condensing unit with an under dash evaporator/fan cab unit.


I don't know if this is a factory or an aftermarket unit. I am willing to post pictures and any information I can find  for those who maybe interested.


Take care all.
Robert

[007]

Mine has that set up, under the dash by my knee on the gas pedal side there's a big toggle switch that turns my AC pump on and off for the engine air then I just turned off the heat on the dash or in my case clamp off the hose cuz my valve is bad and turn on the regular blower switch, I had to build a new condenser and fan setup for on the roof because mine was leaking badly I fixed all that, vacuum pump it down and and filled with 134a good to go

[RCND]

Hello 007:


Was your system originally set up for R12. If it was, did you flush the old oil out of the compressor, evaporator and hoses?


The reason I ask is that the mineral oil used in R12 systems is not suitable for R134a. The r134a is a smaller molecule than r12 and will leak out through the original hoses.


R134a uses a thicker type of oil, commonly PAG oil, that coats and seals the inside of the hoses. PAG oil is not compatible with the R12 oil and will cause problems.


Take care.
Robert

[007]

good morning Robert, I just fixed the leaks sucked it down and filled it up never added or removed any oil , it was r12 and I've heard that for years never worried about it, did the same to my buddys old ford 3/4 ton 5-6 year ago just had to give it a shot two weeks ago, it was still cold , now its really cold lol  a month ago I bought a pipe tap and recharged a window ac I had sitting around figured what the heck... give it a shot or throw it away, worked like a champ i?? is it the right way... no but cold is cold :)rotflmao :)rotflmao  have 30 lbs 134a will travel, have a great day, mark

[Froggy1936]

My roof A/C adapted from a 1989 Trailer was not putting out enough cold ,R22 system .After a night of running it would do OK  There are no visible leaks (oil stains) I contemplated updating  $ 503.00 . So before throwing it away I tapped it , And installed 2 cans of R134  . (R 22 is no longer available or extremely expensive )  It has been running and putting out 55o Temps for a couple months now making the experiment well  worthwhile !    Frank

[Rickf1985]

When they decided to change everything over I had to go to the classes to get my new certification for recycling and have the R134 added to my refrigeration cert. They told us that you have to replace the receiver/dryer and dump the oil out of the compressor and measure it for replacement with pag oil. The little mineral oil that left in the lines and evaporator and condenser would not affect the operation of the unit. I have done probably over a hundred conversions and the number of failures could be counted on both hands. These failures were all on high mileage units and all were consistent with a high mileage type compressor failure. So it was concluded in every case that the compressor failed due to use and not the conversion.

[RCND]

Howdy All:


Yes the ester oils work with R134a systems and mix effectively with the old mineral oils. They were developed for the conversion of R12 systems over to R134a.


The Freon classes of refrigerants are essentially solvents, the mineral oil would be suspended and carried through out the system thus lubricating the compressor. R134a alone does not have this ability to mix with the mineral oils. This is one reason for the compressor failures.


The problem with mixing mineral oil used in R12 systems with PAG is that it forms a sticky/tacky mixture that also creates a loss of lubrication for the compressor.


Just passing information on. You take care.
Robert