Air conditioning update
07-21-2016, 08:47 PM
#1
Racer
Thread Starter
Air conditioning update
I'm looking for recommendations for my 1986 Carrera targa in Connecticut. Probably a decade ago, the dealership no longer had R12 and the air-conditioning has been warm since then. We used to get recharged every year or two. In the interval, I've been doing all the maintenance myself and enjoying every minute of it. I think all the existing equipment functions.
It's come time to get the air conditioning working again. I will admit it's beyond my abilities/available time.
Can anyone recommend a shop in Connecticut? What should I do to get it converted to R134A?
It's come time to get the air conditioning working again. I will admit it's beyond my abilities/available time.
Can anyone recommend a shop in Connecticut? What should I do to get it converted to R134A?
07-23-2016, 02:21 PM
#4
Drifting
First and foremost, get the work done ONLY by an A/C specialist shop/technician, do not use any Porsche, or multi-purpose, shop as they are not likely to understand the basic A/C functionality.
Most specialists shops can/will do the conversion to R-134a for less than $200.
Most specialists shops can/will do the conversion to R-134a for less than $200.
07-23-2016, 02:30 PM
#5
Drifting
a/c
Read the entire thread...
Hi guys,
It's been a while since I've updated this thread. I had a compressor seal leak and replaced the unit under warranty. Hopefully this will hold up. Anyway I was in the process of charging my system, today:
OAT = 84 degrees F.
High side 220 PSI
Low side 24 PSI
Vent temps 29.5 to 31.5 degrees F.
Then I noticed my High side pressure suddenly drop to 150 PSI. WTF?
It took me a moment to realized my rear condenser fans had just turned on! I disconnected them and the pressure slowly went back to 225 PSI. Reconnected the fans and pressure again dropped to High side of 150 PSI.
Now I am running dual condenser fans plus the electric engine compartment fan as an exhaust fan in the engine compartment. My idle speed is 800 RPM.
My conclusion is that rear condenser fans really do work at idle. They may not add much at higher RPMs or when moving at high speeds. The condenser fans are activated by a 130 degree F. switch that clamps onto my compressor discharge pipe. If they are not needed at speed, as evidenced by a cooler discharge pipe, the fans should shut off.
As a side note, I could not detect any rising of my High side pressure when I turned off my engine, even though it was fully warmed up. The low side started rising and the high side began to fall. They were back in the 70's PSI in 30 minutes.
I know it was a relatively cool day to perform this experiment, but that's what I got.
Thanks to all,
Dave
It's been a while since I've updated this thread. I had a compressor seal leak and replaced the unit under warranty. Hopefully this will hold up. Anyway I was in the process of charging my system, today:
OAT = 84 degrees F.
High side 220 PSI
Low side 24 PSI
Vent temps 29.5 to 31.5 degrees F.
Then I noticed my High side pressure suddenly drop to 150 PSI. WTF?
It took me a moment to realized my rear condenser fans had just turned on! I disconnected them and the pressure slowly went back to 225 PSI. Reconnected the fans and pressure again dropped to High side of 150 PSI.
Now I am running dual condenser fans plus the electric engine compartment fan as an exhaust fan in the engine compartment. My idle speed is 800 RPM.
My conclusion is that rear condenser fans really do work at idle. They may not add much at higher RPMs or when moving at high speeds. The condenser fans are activated by a 130 degree F. switch that clamps onto my compressor discharge pipe. If they are not needed at speed, as evidenced by a cooler discharge pipe, the fans should shut off.
As a side note, I could not detect any rising of my High side pressure when I turned off my engine, even though it was fully warmed up. The low side started rising and the high side began to fall. They were back in the 70's PSI in 30 minutes.
I know it was a relatively cool day to perform this experiment, but that's what I got.
Thanks to all,
Dave
07-23-2016, 02:32 PM
#6
Three Wheelin'
I am also interested and live in CT.
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07-24-2016, 09:26 AM
#9
Rennlist Member
I had the r-134 update on my 1985 911 a few years ago. Components checked for leaks, and checked out OK. But I did not do the barrier hose replacement, and I loose r-134 over time. I will soon have the engine dropped for RMS replacement, and I was considering installing new hose at that time because it is my understanding that the barrier hose can leak slowly over time.
I am torn between replacing the barrier hose, or just removing the drive belt from the A/C and forgetting about the A/C altogether. If it's really hot, I have something else to drive.
Any thoughts would be appreciated. Thanks, Mike.
I am torn between replacing the barrier hose, or just removing the drive belt from the A/C and forgetting about the A/C altogether. If it's really hot, I have something else to drive.
Any thoughts would be appreciated. Thanks, Mike.
07-24-2016, 10:42 AM
#10
"Barrier" hoses do not leak perse.
Stock non barrier hoses leak.
R&R of the 5 hoses takes 8 hours, floor jack and 4 jack stands; standard tools.
You'd replace all the o-rings and drier while you are at, add refrigerant
oil, evac, charge and test.
Some hose suppliers
include a binary low high pressure switch to help protect the system; and detailed installation, evac and charging instructions, and tech support.
Depending upon the miles on your compressor you might want to open it up, inspect the bores, pistons, wobble plate and if all looks good just toss in a seal kit, or if things are south pick up a new Denso (84-89 years).
The only other possible leak item in your case (86-89 years) is the evaporator; copper bonded to aluminum. If you are R&R hoses you might as well pull the evaporator out of the box, inspect it, and reseal it (the foam on the sides of the coil rots and air b-passes the coil).
If your front condenser blower motor does not have an inline fuse, splice one into the hot wire at blower (7-10 amp).
There is no need to drop an engine to R&R hoses.
You got 3-4 more months of AC weather depending upon your location.
Stock non barrier hoses leak.
R&R of the 5 hoses takes 8 hours, floor jack and 4 jack stands; standard tools.
You'd replace all the o-rings and drier while you are at, add refrigerant
oil, evac, charge and test.
Some hose suppliers
include a binary low high pressure switch to help protect the system; and detailed installation, evac and charging instructions, and tech support. Depending upon the miles on your compressor you might want to open it up, inspect the bores, pistons, wobble plate and if all looks good just toss in a seal kit, or if things are south pick up a new Denso (84-89 years).
The only other possible leak item in your case (86-89 years) is the evaporator; copper bonded to aluminum. If you are R&R hoses you might as well pull the evaporator out of the box, inspect it, and reseal it (the foam on the sides of the coil rots and air b-passes the coil).
If your front condenser blower motor does not have an inline fuse, splice one into the hot wire at blower (7-10 amp).
There is no need to drop an engine to R&R hoses.
You got 3-4 more months of AC weather depending upon your location.
Last edited by griffiths; 07-24-2016 at 01:00 PM.
07-24-2016, 12:56 PM
#11
Rennlist Member
Griffiths, your knowledgeable reply is a wonderful example of why this group is so valuable! Thank you.
The reason I mentioned the engine drop was it was going to be dropped anyway, and I thought that would make it easier.
The reason I mentioned the engine drop was it was going to be dropped anyway, and I thought that would make it easier.
07-24-2016, 01:02 PM
#12
Engine drop... will save you 4 minutes with the 2 ac hoses in the engine bay.
Don't forget to inspect your 3 primary fuel lines on the motor while you have it out, R&R of those
fuel lines with an engine out saves you 5 hours of work.
Don't forget to inspect your 3 primary fuel lines on the motor while you have it out, R&R of those
fuel lines with an engine out saves you 5 hours of work.
07-24-2016, 04:36 PM
#13
Drifting
Once I installed a trinary pressure switch in my 88 Carrera 3 years ago I have not had to refill nor top off the R-134a even once.
High side pressure is limited to 325 PSI by the switch.
The third switch element is used to activate an extra rear condenser cooling fan plus the cabin heater blower. Recently added a time delay relay that will allow these to fans to activate, or remain activated for up to 15 minutes post engine shut down.
Copped the idea from the 89+ 911 series.
Was somewhat surprised to have that circuit actually work, fans came on a minute or so post engine shut down, during our recent warm (hot?) weather spat.
Restricting, preventing, refrigerant high pressure excursions may well be another way to prevent non-barrier hose leakage.
No one disputes that installing a binary pressure control switch is literally a requirement, should have have been factory supplied. Conversion to r-134a will result in higher operating pressures vs R-12 so installing a pressure switch is highly recommended.
The cost of a trinary switch vs a binary switch is negligible and the system functionality will be greatly enhanced.
High side pressure is limited to 325 PSI by the switch.
The third switch element is used to activate an extra rear condenser cooling fan plus the cabin heater blower. Recently added a time delay relay that will allow these to fans to activate, or remain activated for up to 15 minutes post engine shut down.
Copped the idea from the 89+ 911 series.
Was somewhat surprised to have that circuit actually work, fans came on a minute or so post engine shut down, during our recent warm (hot?) weather spat.
Restricting, preventing, refrigerant high pressure excursions may well be another way to prevent non-barrier hose leakage.
No one disputes that installing a binary pressure control switch is literally a requirement, should have have been factory supplied. Conversion to r-134a will result in higher operating pressures vs R-12 so installing a pressure switch is highly recommended.
The cost of a trinary switch vs a binary switch is negligible and the system functionality will be greatly enhanced.
07-24-2016, 04:41 PM
#14
Drifting
07-24-2016, 04:52 PM
#15
Drifting
From that post series
Hi guys,
It's been a while since I've updated this thread. I had a compressor seal leak and replaced the unit under warranty. Hopefully this will hold up. Anyway I was in the process of charging my system, today:
OAT = 84 degrees F.
High side 220 PSI
Low side 24 PSI
Vent temps 29.5 to 31.5 degrees F.
Then I noticed my High side pressure suddenly drop to 150 PSI. WTF?
It took me a moment to realized my rear condenser fans had just turned on!
I disconnected them and the pressure slowly went back to 225 PSI.
Reconnected the fans and pressure again dropped to High side of 150 PSI.
Now I am running dual condenser fans plus the electric engine compartment fan as an exhaust fan in the engine compartment. My idle speed is 800 RPM.
My conclusion is that rear condenser fans really do work at idle.
They may not add much at higher RPMs or when moving at high speeds. The condenser fans are activated by a 130 degree F. switch that clamps onto my compressor discharge pipe. If they are not needed at speed, as evidenced by a cooler discharge pipe, the fans should shut off.
As a side note, I could not detect any rising of my High side pressure when I turned off my engine, even though it was fully warmed up. The low side started rising and the high side began to fall. They were back in the 70's PSI in 30 minutes.
I know it was a relatively cool day to perform this experiment, but that's what I got.
Thanks to all,
Dave
It's been a while since I've updated this thread. I had a compressor seal leak and replaced the unit under warranty. Hopefully this will hold up. Anyway I was in the process of charging my system, today:
OAT = 84 degrees F.
High side 220 PSI
Low side 24 PSI
Vent temps 29.5 to 31.5 degrees F.
Then I noticed my High side pressure suddenly drop to 150 PSI. WTF?
It took me a moment to realized my rear condenser fans had just turned on!
I disconnected them and the pressure slowly went back to 225 PSI.
Reconnected the fans and pressure again dropped to High side of 150 PSI.
Now I am running dual condenser fans plus the electric engine compartment fan as an exhaust fan in the engine compartment. My idle speed is 800 RPM.
My conclusion is that rear condenser fans really do work at idle.
They may not add much at higher RPMs or when moving at high speeds. The condenser fans are activated by a 130 degree F. switch that clamps onto my compressor discharge pipe. If they are not needed at speed, as evidenced by a cooler discharge pipe, the fans should shut off.
As a side note, I could not detect any rising of my High side pressure when I turned off my engine, even though it was fully warmed up. The low side started rising and the high side began to fall. They were back in the 70's PSI in 30 minutes.
I know it was a relatively cool day to perform this experiment, but that's what I got.
Thanks to all,
Dave