High pressure on high side after AC rebuild

[SLOWoody]

The ambient temp reading is from a thermometer on my garage door opener (69F) and the readings from my condenser output was done using an IR (non-contact) thermometer. The emissivity setting on the IR gun needs to be set to match the emissivity of the surface that is being measured but without knowing the emissivity of that surface material the IR temp gun will not give a proper temp reading. I plan on using a surface contact thermocouple this weekend to get accurate readings.

I double check the flow direction for the dryer when I installed it but will check it again. The line exiting the evaporator is not iced over but it is sweating a bit. I have not climbed under the van yet to check temp of the low pressure hose from evaporation valve to compressor.

[ice-n-tropics]

OK, the system was clean before SD7H15 installed. Extra 2.2 oz oil is OK. Oil can be removed by idling engine 5 min. so that oil collects in crankcase. Then remove and drain compressor.
The H20 Vanagon AM AC had an optional (& desirable) auxiliary rear AC with a solenoid valve in the rear liquid line that needs 3 more ounces (120cc) of oil.
hotrodac

[SLOWoody]

OK, the system was clean before SD7H15 installed. Extra 2.2 oz oil is OK. Oil can be removed by idling engine 5 min. so that oil collects in crankcase. Then remove and drain compressor.
The H20 Vanagon AM AC had an optional (& desirable) auxiliary rear AC with a solenoid valve in the rear liquid line that needs 3 more ounces (120cc) of oil.
hotrodac

Do you have any other suggestions for me to try in order to solve my high side high pressure? I hear you are the expert.

[Tim]

OK, the system was clean before SD7H15 installed. Extra 2.2 oz oil is OK. Oil can be removed by idling engine 5 min. so that oil collects in crankcase. Then remove and drain compressor.
The H20 Vanagon AM AC had an optional (& desirable) auxiliary rear AC with a solenoid valve in the rear liquid line that needs 3 more ounces (120cc) of oil.
hotrodac

Do you have any other suggestions for me to try in order to solve my high side high pressure? I hear you are the expert.

Not too many use "Computer Duster" refrigerant around here.

[ice-n-tropics]

T Bird say it truly. Lots of great advice around here.
Stationary testing is inferior to road speed evaluation with ram air. You can route the gage hoses inside the cabin and get better data. Maybe the hot radiator outlet air is recirculating while stationary and gets worse as the radiator temp increases.
Condenser pusher fan helps.
Air in system BAD.
Overcharge BAD.
Outside air into cabin and evap BAD.
Excessive oil BAD.
TIm's advice is spot on.
65 degree condenser out is only possible if there is a abnormal restriction .
hotrodac
.

[SLOWoody]

Thanks everyone for all of the advice so far, I now have a few things to test and try out. I will report back after I get a chance to work on Van-Go (our 83.5 Vanagon Westy) and take more accurate temp readings, hopefully this weekend. Rebuilding this AC system has been a big learning experience for me and happy to get advice from such a great knowledge base.

[tbirdtbird]

Please report back how you make out, it helps everyone. Good luck.

[SLOWoody]

I have solved my high side high pressure issue, it was simply overfilled. While initially charging the new system there were some wiring issues with the radiator fan which caused bad pressure readings when not enough air was blowing across the condenser. This caused me to end up over filling the system unknowingly. I determined this by relieving pressure for a while and then finally the high pressure started to decrease. I continued releasing refrigerant until I got to the readings below. Now my low and high side pressures are close to normal and the vent temp is around 37F.

Here are some detailed values after I got the system working well, temperature readings were taken with a contact thermocouple:
Ambient Temp: 77F
Compressor out temp: 151F
Condenser in temp: 150F
Dryer in temp: 100F
Evaporator in temp: 18F
Evaporator out temp: 27.2F
Compressor in temp: 27.4F
@1000rpm: Low pressure: 25psi High pressure: 190psi Vent temp: 41F
@2000rpm: Low pressure: 17psi High pressure: 250psi Vent temp: 37F

Now I would like to fine tune the system to get the optimal cooling. Can anyone give me tips on how I might fine tune this AC system? Should I just fill/release refrigerant until I get the coldest vent temps? What rpm should I be do this at? Is there a better technique?

[Cusser]

I think you were lucky/fortunate.

I'd leave the system where it is, your vent temperatures look fine.

[Tim]

I'd leave the system where it is, your vent temperatures look fine.

Yep!