LuckyNLife

I am trying to diagnose my A/C system. It was converted to R134A by the PO and has not been recharged in over 3 years. The compressor will not turn on. I ran a jumper to it and the clutch is engaging. When I took a static reading on the ports, the high-side and low-side are both reading 20psi. Is this high enough to trigger the low pressure switch or should I try to add more R134A to kick it on? Has the compressor failed and that is why the pressure is equal on both sides? Any help on moving forward would be appreciated.

Thanks,
Joe

cjoenck

After 3 years with the old lines - I assume the lines were not changed - even without an obvious leak, you are most likely empty. That's why the compressor doesn't kick in. You need a complete refill, I think.

r-mm

Static pressure readings do not indicate anything besides total absence of refrigerant, they change based on environmental conditions not charge level. Static pressure should be equal hi/lo if the AC has not run for a few hours. There is little harm in adding a bit of refrigerant as you can always have it all evacuated and charged to the right level. Its easy to over charge the system and have it perform badly, look at Porsche's doc I believe its 840g which results in lower running pressures than many would presume. If it were mine I'd probably add a little to verify the compressor runs then evacuate it all, pull a nice long vacuum then charge by weight.

I presume you checked all the fuses. Does the light on the ccu come on?

LuckyNLife

That is exactly what I did yesterday. I added R132a till it reached ~40psi on the low side. The compressor kicked in. I then added a bit more to meet the midway point for the specified psi for both the low-side and high-side based on the outside temperature at 2,000 rpm. It worked. 45 degrees at the vents. I don't believe it is over charged, so I am going to see how this works for a while and will refurb the A/C system over the winter. I added a bit more to meet midway point between the specified psi for both the low and high sides based on the outside temp. Sure enough, it worked! 45 degrees at the vents. I added a bit more to meet midway point between the specified psi for both the low and high sides based on the outside temp. Sure enough, it worked! 45 degrees at the vents. a bit more to meet midway point between the specified psi for both the low and high sides based on the outside temp. Sure enough, it worked! 45 degrees at the vents.

r-mm

45 at the vents is good stuff. I cleaned my condenser, replaced and tested fan ballast, replaced drier, cleaned compressor replaced oil and charged to 840g exactly and can just scratch 50 degrees most days. If the charge lasts the summer I'd frankly leave it. It ain't getting much better.