DPD Air Conditioning for type 2 bus? FAQ

[jonnydot]

I have a one of these over head units and an under dash unit and wanted to set both up what pump would you suggest I use ?

[69BahamaYellow]

Denso 10PA17C compressor has been bulletproof in my bus.

[jonnydot]

Hi Guy's I hail from Goonellabah Australia. I have managed to acquire a DPD over head unit (rare as rocking horse shit in Aus) It is pretty much complete. I wish to set it up using an electric pump ,whilst I am fairly adept at mechanical installations/repairs I have no knowledge of what size pump I will require and what information I need to glean to instigate a search for the little beasty. As I will be doing a bare metal restoration I am able to fully insulate the bus (1976 Camper 2.0 engine) to minimize heat transference and leakage of cool air and ingress of hot. SOOOO one and all what do I need? can I pull a unit and high voltage network from a Prius or some other vehicle and what amperage alternator should I use? Suggestions Please and many thanks for reading

[tommu]

[69BahamaYellow]

Electric AC compressor will need to be 20,000 to 30,000 BTU capacity to cool a bus, which will probably require an extra 160-240 amps from a 12V system. Once you add another 60-70 amps required to run the cooling fans and the rest of the electrical system, you need over 300 amps.

I’m sure there’s a commercial duty Alternator out there somewhere that would produce that much power, just have to figure out how to mount it and wire it with cables big enough to handle that much current (think stranded welding cables)

[Duncancarradice]

Just working on the restore on my DPD overhead unit. Was removed from the van when I bought it.

Can’t work out if there are some internals missing or not from the from section. Cold air blows in from the two evaporator fans, each controlled with a seperate 3 speed switch, but the air would just mix and go to whichever vent was open. Don’t see the point of seperate switches then?

Is there some ducting that goes from each evaporator fan to the vent on the same side?

Please post any photos of how you have insulated this on restore

Many thanks

[scrivyscriv]

I removed a DPD overhead assembly from a 1972 bus and installed it on a 71 bus several years ago... this is what it looked like as removed. I assume the dual blowers were the equivalent of "Max A/C" instead of driver/passenger air like a modern car.

_________________
Robert in Memphis
Dünkelgrügen 1967 Java Green bug thread
Engine rebuild thread
If you're ever in the Memphis area, you are welcome to stop by for advice and help.

[Duncancarradice]

[69BahamaYellow]

I made my own internal baffles out of polystyrene foam to separate left and right side air from the fans. Wish I had taken some pictures of it, but I highly recommend lining the interior of this duct with some kind of encapsulated foam insulation (something that won’t absorb water). The plastic gets very cold otherwise and will sweat condensate all over you. I don’t have this problem on mine but I have heard from others, who did not insulate theirs, that it will sweat badly

[Duncancarradice]

[69BahamaYellow]

That looks great! Decent examples of those old DPD parts are getting hard to find.

I remember using 1/4" semi-rigid polystyrene foam insulation from Home Depot. You can buy it in large sheets and just cut the pieces you need and trim to fit with scissors. You can sandwich them together to make left and right side channels to the vents, and spray on latex based contact cement works great to stick everything together (regular contact cement will melt the foam). After I glued all the foam lining and air channels in place, I cut a piece of foil backed fiberglass insulation and taped it over the top with aluminum tape. I found that the extra padding from the insulation also protects the headliner from the sharp edges of the plastic and just makes the whole thing quieter.

The only other thing I wish I had done is to replace the 3 position fan switches and resistor blocks with modern Pulse Width Modulated (PWM) switches. This gives full variable speed operation of the fans with no electrical losses. On my system, I find the middle setting to be not much more than the low setting, so I'm always using either the lowest setting or the highest, but somewhere in the middle would be nice. I've also found the dual fan controls are very valuable, if you have passengers that like more or less air than you do. The fans are very powerful.

[Duncancarradice]

This is how I've done mine. Wasnt able to get any EPS/XPS board less then 10mm thick, used stick on flexible closed cell foam instead and polystyrene channel down the middle. PWM switches are on the way. The cork tape was way too heavy and not sticky enough to use for this purpose

[Balidas]

Just picked up this style last week. Drove 4 hours one way to get it but it will be worth it. Unit looks like it could put out some near hurricane force winds.

I have no clue what year this is.

The other 2 parts.

This is the worst of the damage I have here. I could probably fix that with JB Weld.

I have already taken things apart. I'm going to pull all the glued down mats & possibly replace it all with this;

https://www.eastwood.com/hushmat-1-4-silencer-mega...22410.html

This should also help to reinforce these pieces to prevent breaking, splitting....

After prepping I'm thinking to spray the outsides with Raptor Lining. Hopefully to help prevent these pieces from disintegrating into dust like I've seen so many other pieces do.

[telford dorr]

I've got the DPD overhead unit in my '71 panel. It used to work good, but the expansion valve failed (low side pressure ~20 psi, high side ~140 psi). Anybody know of a generic replacement part (same size / flow rate)?
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)

[skills@eurocarsplus]

[SGKent]

[telford dorr]

Steve:
Yes, it does have a sight glass, which was, curiously, the failure point - its seal failed. Installed a new o-ring, pressurized and leak tested the system - no more leaks. Oil in pump OK. Did a purge and recharge with Aeromech (he has a refrigeration vacuum pump). Worked good for a while. One day, no more cold. Put the gauges on it and found the low side pressure very low and the high side normal to high. Compresssor drive belt under high load. Used to be able to hear the freon bubbling thru the evaporator - now, nothing. Obviously, no refrigerant flowing.

Yes, I have enough R12 for a charge. {NOT for sale...}

Don:
When I get ambitious, pull the unit back off the ceiling, and get the black stuff removed, I'll p/m you with a pic of the valve.
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)

[SGKent]

[78BusGA]

In Northeast Georgia I saw a nearly gutted 1974 tintop with the internals of the DPD intact. Is it worth pulling that for spares when I eventually get to my 1978, or will they be too different?
_________________
Few will understand the passion and majesty, among the nuts and grease.

Tom H.

My '74 Super 1303 thread - https://www.thesamba.com/vw/forum/viewtopic.php?t=764902&start=60

My '78 Kombi Bus thread - https://www.thesamba.com/vw/forum/viewtopic.php?t=769385&highlight=

'72 Superbeetle (retired), '78 Bus Kombi 2.0FI, '74 1303 Superbeetle

[SGKent]