ARA Dash Air Conditioners

[Keyair]

Good thread!
If money were no object, I would probably be talking to "Vintage Air" about a system, or at least the internal components and control system! They have some great solutions!

[Kota]

Originally Posted by Keyair

Good thread!

If money were no object, I would probably be talking to "Vintage Air" about a system, or at least the internal components and control system! They have some great solutions!

I talked to vintage Air a couple years ago. Not very helpful. If you couldn't rattle off a vehicle like a 56 T-bird that they had a kit for, they wouldn't talk to me.

[Isuzusweet]

Okay Kota, at the meet we took a ride in your Jeep which you exclaimed had the coldest A/C you've ever had.......Now I know that compressors are for the most part the same, yes, some bigger than others, but if we could somehow take the condenser, dryer/evaporator and a compressor with similar specs to your Jeep and put it into our Classics; why wouldn't it work?

Yes, there would be some butchery and zip ties involved, but taking all the components out of your Jeep? Why not?

Cheers
Tony

[bobmiller1]

Dave, was your system originally R12 ?

[Kota]

Originally Posted by bobmiller1

dave, was your system originally r12 ?

134

[Kota]

Site crashed!

R134. I'm convinced the condenser is way undersized. Wonder if replacing a 30' straight run of hose with a finned aluminum tube would do the trick.

[Air345Fly]

Why do you think that your condenser is too small? In a properly
designed system each component should be the correct size to do it's job.

With that said, things can go wrong. The condenser can get plugged
with road dirt or too many fins can get bent over. These restrict air
flow. If you have an electric fan, it it working OK?

Also, condensers can get plugged inside from krud. This mostly occurs
after a compressor failure. Generally this can be flushed out. However,
newer condensers have many small tubes running in parallel and cannot
be effectively flushed.

From my reading I believe that there is no downside from a too large
condenser. It will just increase the sub-cool which is a good thing.
This is not true for the evaporator where too large a unit will raise
the vent temperature and reduce the dehumidifying effect.

If there is a problem then you can know for sure by measuring the
sub-cool temperature. The process is described at this web site:
https://www.achrnews.com/articles/93...eat-subcooling

That is where I learned what I discussed in my previous post.

The sub-cool can be determined from the R-134a pressure
temperature chart here:
https://highperformancehvac.com/r-13...erature-chart/

This document has useful information:
http://www.aa1car.com/library/macs_s...procedures.pdf

This document shown the condenser construction:
http://www.teamec.be/cms_files/Flush...eaning(EN).pdf

Pete.

[Kota]

Originally Posted by Air345Fly

Why do you think that your condenser is too small? In a properly
designed system each component should be the correct size to do it's job.

With that said, things can go wrong. The condenser can get plugged
with road dirt or too many fins can get bent over. These restrict air
flow. If you have an electric fan, it it working OK?

Also, condensers can get plugged inside from krud. This mostly occurs
after a compressor failure. Generally this can be flushed out. However,
newer condensers have many small tubes running in parallel and cannot
be effectively flushed.

From my reading I believe that there is no downside from a too large
condenser. It will just increase the sub-cool which is a good thing.
This is not true for the evaporator where too large a unit will raise
the vent temperature and reduce the dehumidifying effect.

If there is a problem then you can know for sure by measuring the
sub-cool temperature. The process is described at this web site:
https://www.achrnews.com/articles/93...eat-subcooling

That is where I learned what I discussed in my previous post.

The sub-cool can be determined from the R-134a pressure
temperature chart here:
https://highperformancehvac.com/r-13...erature-chart/

This document has useful information:
http://www.aa1car.com/library/macs_s...procedures.pdf

This document shown the condenser construction:
http://www.teamec.be/cms_files/Flush...eaning(EN).pdf

Pete.

Properly designed is the key. Compared with my Ram, Wrangler, Explorer, and other vehicles I've had with awesome AC, the condenser is minuscule. About 16" by 20" with a 14" fan. Think that's all that would fit in the location they chose on the DP. I've never seen a 360 with dash AC that put out anything useful if the ambient temp is above 75 degrees. I do understand that the dash air will not come close to cooling the coach. But, if it put out the volume and temp of my little Jeep Wrangler, with nicely focused vents, we could be very comfortable. Add cooled seats and it would be quite pleasant.


Here's a link to parts if it hasn't been posted.

http://acmeairparts.com/

[Air345Fly]

Your condenser does sound small. I measured my unit at 29" X 18" with
two electric fans and the large engine fan.

I bought my 345 a few months ago and have never had the A/C working
so I don't know what it is like. I understand that it will not cool the
while motorhome but if is gives a blast of cold air in my face as I am
driving along then i will be satisfied.

If your condenser is so small then the other components are likely to
be sized comparably. What compressor do you have? Different
compressors have different displacement. The displacement times
the driven RPM will give you the power available. The evaporator,
condenser, and the orifice will be sized to handle that power. You
are not going to get more cooling than is available from the power
provided by the compressor.

Pete.

[Kota]

Understood. There are a lot design flaws in the system or at least in the implementation. The compressor has a double v belt drive. They couldn't work it in to the serpentine so they drove it off the fan with a single belt. Couldn't fit a double pulley on the fan. The fan is driven by less than 90 degrees of serpentine contact. Belts fail and the serpentine squeals occasionally.

The push pull cable for the water valve is poorly routed. They all seem to fail at the control head. The vacuum valve module has a block connector that leaks as they age. The heater cores develop leaks. The replacements are a new and vastly improved design. Gotta free the drier from its mount to get a gauge on the fitting.

Do to the limited number of these things (26?), I'd say that not a lot of engineering went into the system.

Don't look under the dash on these things. Embarrassing mess!

[Air345Fly]

I have been pulling my dash apart and am glad that the heating and
A/C unit is not under there unlike most cars.

My compressor has a dual pulley but only one drive belt. But it
does go around the engine pulley and the fan pulley. I think that
the belt drive design is good.

Do you have the big block 454 engine?

I have been trying to understand what operates the vacuum controlled
door flap at the bottom of the heating and A/C unit behind the
passenger kick panel. I assume that it goes to the valve on the
control panel.

When I removed the air injection system I had to re-do all of the
vacuum lines on the engine. What a mess, even the sticker on the
air cleaner did not accurately describe the vacuum system. I still
don't have it right.

When I get into these things I can't leave it until everything works.

Pete.

[bobmiller1]

LOL, I hear you, I re did all the lines on the 325LE, and the R12 AC works perfectly. Thank goodness nobody messes with the original routing of the lines because it made it alot easier to replace all the lines. I am still working on the 370LE lines and should have that and the dashboard controls completed over phase 2 of the overhaul. Regards, Bob

[Kota]

Originally Posted by Air345Fly

I have been pulling my dash apart and am glad that the heating and
A/C unit is not under there unlike most cars.

My compressor has a dual pulley but only one drive belt. But it
does go around the engine pulley and the fan pulley. I think that
the belt drive design is good.

Do you have the big block 454 engine?


Pete.

The little block Cummins 5.9. And it's in the rear. AC is vacuum controlled via electric vacuum pump. I'd really like to convert it to electric actuators and control panel.