In-dash air conditioner - Worth converting or fixing?

[DaHose]

I have an older Jamboree I am breathing new life into and cost is a concern. Our in-dash air conditioner is dead and I am mulling over converting it to R134A. However, I have seen some posts comment that the dash A/C is nowhere near enough to cool the RV on hot days and that it makes more sense to just run the gen. set and rooftop A/C.

If you had a 1983 Jamboree (26'), would you bother to repair/convert the in-dash A/C to R134A, or just forget about it and use the rooftop any time you wanted to cool the rig down?

Jose

[DaHose]

Thanks j-d. Your help along the way made it possible. Now we have a roadmap for anyone else who might want to change their compressor in the future.

Jose

[j-d]

Jose did a very skillful job with the conversion and the documentation! I wanted to do that on one we had but I let a critical part get away. Also, I thought it'd need welding and I don't weld. There used to be compressor conversion brackets, don't know if I can still find them.
The real challenge is actually the compressor hose ports.
Again, Great Job, Jose!

[DaHose]

Thanks for the tip, Dusty. I'll be sure to leave the slider in defrost mode at all times.

I changed the refrigerant to R12A, Hank. It cools great with no additional modification, takes less product to charge the system and doesn't even need vacuum to charge. Since the bulk of the system components are at the open front of the engine bay (not near the headers) I am comfortable running an isobutane based refrigerant. On my M6, the A/C lines run all along the "hot as hades" headers. I am NOT comfortable running R12A in that case.

Jose

[JaxDad]

snowdance wrote:

noe-place wrote:
Dash unit won't cool beyond the pilot/co-pilot area. DW runs the genny and roof AC when things get too hot. Let your wallet make the decision for you.

The dash AC will cool the complete rig if you open a roof vent or some thing near the rear of the rig so the air can go thru. It is air coming in and if it has no place to go it will stay right there and do only the cab area. If you have roof vent covers while going down the road with the vent open some it will form a vacuum amd pull the air from the cab AC thru the complete rig. Our complete rig stays cool even in 114 degree temps. Roof AC will not do as well.

Ditto!

While rolling down the highway my dash unit will cool the whole rig as well or better (it's higher got higher cooling capacity, but a smaller fan) than the rooftop unit will.

[Hank85713]

we converted an R12 system to 134 in a small van we had at one time. Nothing but a nightmare since the 134 requires a larger evaporator and other things. The place we had it installed went thru 2 compressors and 1 new evaporator before finally recommending going back to R12.

So if you are really researching plan on replacing more than just the juice. I am sure there are some that will say it works but just how well they never say. Just my Opinion however based on experience.

[Dusty_R]

When the sun shines on the windshield, it heats the glass and the glass radiates infrared heat into the mh. To counteract this turn your defrosters on. The AC runs when the defroster is on, this will cool the windshield.


Dusty

[DaHose]

Hello, everyone. I have a final update to this post. I have completed my dash A/C repair/conversion and documented it. Below is a link to the document.

York to Nippondenso A/C Compressor Conversion

In a nutshell. The Nippondenso 6P compressor is a GREAT upgrade. I also charged it with R12A and it performs really well.

Hope the document is helpful to someone, someday. 🙂

Jose

[Dastagg]

When my dash unit quit cooling, I tried using house ac and gen set with fan blowing in cab area. Way too uncomfortable in Southeast Texas heat. Got it fixed and now only need cab ac while traveling and MH is cooled some when stopped. Maybe not to set temp in MH, but dash unit cools pretty good while traveling. Definately would fix it. Past experience in heat requires it for me!

[crawford]

Sounds like way to many experts in AC repairs to me and retro fits kits to me. LOL.

[snowdance]

noe-place wrote:


Hey that's interesting. Do you have your AC set on re-circulate position when doing this?

If you set your AC on re-circulate it does not bring in more air so air inside moves only in the cab area.

If you bring in out side air it will move thru the rig. In a lot of ways air acts a lot like water. If you keep adding air to the inside it flows thru. That keeps the whole rig warm or cool. Hard part is trying to get people to open a rear vent in cool or hot weather because they think the out side air will come in but if you keep warm or cool air coming in thru the cab heater/AC it will only exit the rig. And it will exit at the rear so goes thru the rig. Faster you run the heater/AC fan the faster it heats/Cools the rig. Most Cab AC's are some where around 50,000 btu. Most roof ACs are about 1300-1500 btu.

[noe-place]

snowdance wrote:

noe-place wrote:
Dash unit won't cool beyond the pilot/co-pilot area. DW runs the genny and roof AC when things get too hot. Let your wallet make the decision for you.

The dash AC will cool the complete rig if you open a roof vent or some thing near the rear of the rig so the air can go thru. It is air coming in and if it has no place to go it will stay right there and do only the cab area. If you have roof vent covers while going down the road with the vent open some it will form a vacuum amd pull the air from the cab AC thru the complete rig. Our complete rig stays cool even in 114 degree temps. Roof AC will not do as well.

Hey that's interesting. Do you have your AC set on re-circulate position when doing this?

[DaHose]

I'm with j-d. The mileage loss would be rough. I'm only getting about 6.5 as is. Losing that .5 mpg (or more) would add up to the cost of replacing my compressor in about 10 tank fulls. We do so. cal. trips regularly and that would be at least 5 fills right there. Two trips and I'm in positive returns land.

Jose

[j-d]

What I heard about the R134A systems was to try and have the High Side not higher than 2.2 x Ambient, so 220 PSI at 100*F Ambient.

When I tried to charge our "Dealer Air" on a rig like Jose's up to Low 20's Low Side (with 134), the Compressor got balky. Clutch Hub would STOP! Either the Belt or the Clutch itself would slip and squeal. I hooked up the High Side gauge and it was in the upper 300's! All this on an old afermarket system with the old stainless worm-drive hose clamps! That was when I knew I had to back off the charge. Low side was running in the low teens before High dropped into the 200's. I still couldn't use "store brand" belts. Had to be NAPA, Dayco, Gates, etc.

But yes, it cooled. At a cost of at least 0.5 highway MPG, and when 8 (A/C Off) is a Personal Best, need to get the compressor efficiency up. That's why I suggest converting to an Axial Compressor.

[snowdance]

noe-place wrote:
Dash unit won't cool beyond the pilot/co-pilot area. DW runs the genny and roof AC when things get too hot. Let your wallet make the decision for you.

The dash AC will cool the complete rig if you open a roof vent or some thing near the rear of the rig so the air can go thru. It is air coming in and if it has no place to go it will stay right there and do only the cab area. If you have roof vent covers while going down the road with the vent open some it will form a vacuum amd pull the air from the cab AC thru the complete rig. Our complete rig stays cool even in 114 degree temps. Roof AC will not do as well.