Driver's A/C questions

[Skykingrob]

Folks
I have read what is in the archives and am still looking for a solution. During my search, I spoke to one a/c designer who told me a couple of things I am trying to verify.
1. He said with the long run of the bus, if I was going to go with a smaller engine driven compressor, it would be better to mount the condensor in the front spare tire compartment to keep the liquid lines as short as possible. He has several condensor types on his web site, most of which are designed for remote, non-radiator mounted situations with single or multiple circular rotary fans.
2. He said, if I planned to keep the standard Prevost evaporator and find a compressor to mate with it, I needed to find out the BTU rating of the evaporator. I called Prevost who referred me to the company who designed the Prevost system. I sen them a messge and have not heard anything from them. Not sure I ever will but the question is does anyone on the board know what the BTU rating is. If not does anyone know a formula of how to calculate the BTU rating. I searched Google with no luck and the a/c guy did not know one to suggest. The second part of this question has to do with the compressor. He said if I planned to use the Prevost evaporator, I needed to find a compressor that was 33-40% larger in BTU rating to mate with the evaporator. He has number of compressors on his web site but was reluctant to recommend any until he knew the evaporator BTU rating. He said if we didn't choose an undersized compressor for the evaporator, it would not cool correctly.
I would still like to find an electric a/c unit to mount in the spare tire area under the driver and have successfully located two or three different ones but the price is WOW!!. For 6,000 BTU, $2790.00 to 14,000 BTU, $5985.00. I realize 14K is more than I realistically need. This makes window units much more attractive all the time.
One final question. Has anyone thought about using portable a/c units as auxillary drivers air. I don't recall reading anything about them in the archives. The thing is the more I read about them the less they seem to be an option since they don't seem to cool as well as window units. Most manufacturer's have now solved the water collection situation by spraying it into the hot air exhaust slowly and evaporating it away so you don't have to dump the tank, which is nice. Thoughts?
Thanks

Rob
91 Prevost XL 40
Missouri

[2xclutchin]

I remember a topic brought up about the portable units (just to clarify we are talking about the ones on wheels with a tube that goes outside right?) and it was said that they dont seem to really put out their full BTU rating. I'm no expert and this is all from memory so hope it helps.
Mike

[Nick Badame Refrig/ACC]

Hi Rob,

A good way to find the BTU rating of your evap. coil is to research the TXV [thermo expantion valve] that is attached to the coil for

it's tonnage.  Some TXV mfg's will print the tonnage and refrigerant type right on the valve. For instance, a 1- ton TX valve will equal

12,000 btu's. From there, you will have a better idea of capacity of your evap coil.

Good Luck
Nick-

[stevet903]

Rob - Don't know if this helps at all, but the drivers air of that vintage used a York compressor, which has a max rating of 36,000 BTU.  My 89 has drivers air only, and it has a R-134a expansion valve in it - the part number is 329-404 on it.   Let me know if you need pictures, etc

Steve

[TomC]

I would suggest you call RedDot. They make the A/C system for many of the over the road trucks and buses.  I know on our Thomas school buses, they use two A7 compressors on the rear engine (the old GM designed 6 cylinder compressor) with skirt mounted condensers with electric fans.  Two of these units are enough to cool the entire 40ft bus with passengers.  Much cheaper then trying to keep the huge Carrier compressors running.  Good Luck, TomC

[TomC]

Also Carrier makes alot of coach A/C's of various size.  Your prices are way over what they should be.  Good Luck, TomC

[Zeroclearance]

Skyking and to Prevost owners.   Prevost is having a brake sale and A/C component sale that end this month.   I just purchased a new drivers air compressor for $276..    A brand new Tecumseh unit.   New dryers for $28   

I'm going to have my hands full these coming days.   I bought all new disks, pads and calipers for the bus.   

[luvrbus]

You might should look into the RedDot hydraulic driven compressor unit I know of a couple of Eagle owners that have that unit in the spare tire compartment and are happy with their dash air so far so good 1 has had it for 5 years

good luck

[Skykingrob]

Hi All
Thanks for the answers.
Cliff-yes I looked at hydralic drive compressors of various brands. They are as expensive as the electric units. I have looked at all the red dot and thermo king units plus some off brand.
Tom- I agree the prices are out of touch but that is what they are, which is why I am still looking for more possibilities. The old Carrier compressor from the coach air is long gone and I don't want it back but I am trying to find the best bang for the buck in a dash air unit. According to Prevost the vendor for the a/c system is Mobile Climiate Control in Indiana. I called and sent an email without any response from them.
Steve-According to Prevost the Carrier compressor was 9 ton but I don't have it, don't want it and don't need it. Need a smaller compressor though to fit the smaller system is where I am headed.
Nick-thanks that is helpful. Does what the a/c guy said about size of the compressor (33-40% bigger in BTU rating) make sense and is it right?

Rob
91 Prevost LeMirage XL
Missouri