> Arch, I just had another thought (!!!)
>
> If the rear evaporator (s) are using expansion valves, which is
> the case if
> we use the units from suburbans etc, then we need the compressor
> to run all
> the time. This will mean installing an expansion valve and POA
> valve on the
> front evaporator. Or do we nead a POA? Mark?
>
> But it means we don't have to worry about cycling the compressor and so a
> clutch on the electric motor is back to being unnecessary.
>
> Or that's the current state of my cortexical flatulence.
A POA *would* be a choice for a full run compressor.
I'd lean more toward a solenoid in the liquid line and a conventional
thermostatic expansion valve if the Suburban rear evaps use one. The NAPA
temp catalog used to have all sorts of stuff like this, but I haven't looked
at one for a while. I'll try and get a copy tomorrow.
Unless you're really spinning the compressor, I doubt that you'd freeze up
three evaps unless the air flow is low, temp is low and humidity is high.
Basically, that would be spring and fall in Indiana.
POA valves are big (physically). They also aren't calibrated for 134, which
likes lower low side pressure than R-12. That's the down side.
Individual capillary tube thermostats controlling the high side liquid flow
expansion valve would be my first choice. The last therm to turn off would
stop the compressor. Very simple to implement, individual temp control is
possible, works regardless of compressor speed, etc. The question is whether
these solenoids are still available. The electrical logic would be very
simple to implement.
Again, this is theory, but I do see a good idea jelling up. I had a funeral
viewing today that kept me from making time to get to Acme Air. Perhaps
Monday. I never like to settle on an idea till I know what's out there to
pick from.
I mentioned at work today that I'd like to requisition a '99 Suburban for
"research." Accounting dept looked over the half glasses, tugged down the
green eyeshade and froze the coffee in my cup with a mean stare.
Also, I'll offer that we could schedule a call sometime next week (maybe
Thursday?) to discuss this topic on the phone. Let me know if you're
interested and I'll send you conference bridge instructions. Just a thought.
We can report back on our development ideas so anyone who's interested can
follow along.
Mark
>
> If the rear evaporator (s) are using expansion valves, which is
> the case if
> we use the units from suburbans etc, then we need the compressor
> to run all
> the time. This will mean installing an expansion valve and POA
> valve on the
> front evaporator. Or do we nead a POA? Mark?
>
> But it means we don't have to worry about cycling the compressor and so a
> clutch on the electric motor is back to being unnecessary.
>
> Or that's the current state of my cortexical flatulence.
A POA *would* be a choice for a full run compressor.
I'd lean more toward a solenoid in the liquid line and a conventional
thermostatic expansion valve if the Suburban rear evaps use one. The NAPA
temp catalog used to have all sorts of stuff like this, but I haven't looked
at one for a while. I'll try and get a copy tomorrow.
Unless you're really spinning the compressor, I doubt that you'd freeze up
three evaps unless the air flow is low, temp is low and humidity is high.
Basically, that would be spring and fall in Indiana.
POA valves are big (physically). They also aren't calibrated for 134, which
likes lower low side pressure than R-12. That's the down side.
Individual capillary tube thermostats controlling the high side liquid flow
expansion valve would be my first choice. The last therm to turn off would
stop the compressor. Very simple to implement, individual temp control is
possible, works regardless of compressor speed, etc. The question is whether
these solenoids are still available. The electrical logic would be very
simple to implement.
Again, this is theory, but I do see a good idea jelling up. I had a funeral
viewing today that kept me from making time to get to Acme Air. Perhaps
Monday. I never like to settle on an idea till I know what's out there to
pick from.
I mentioned at work today that I'd like to requisition a '99 Suburban for
"research." Accounting dept looked over the half glasses, tugged down the
green eyeshade and froze the coffee in my cup with a mean stare.
Also, I'll offer that we could schedule a call sometime next week (maybe
Thursday?) to discuss this topic on the phone. Let me know if you're
interested and I'll send you conference bridge instructions. Just a thought.
We can report back on our development ideas so anyone who's interested can
follow along.
Mark
