A\C system recharge following RCV solenoid replacement

Need advice on recharging the A\C system following a simple replacement of the RCV solenoid on my 2006 Jetta with a 1.9L TDI (BRM Engine). I have completed this procedure before with no issues on my other 2006 Jetta, so I’ve had a little experience on the procedure (albeit limited). My question mainly centers around the manifold readings following the upload of the first can of freon. Both the low and high reading seem to remain the same around 105-110 at an ambient temperature of 90 degrees. I realize I have another half can of R134A to add to get the system full, but previously I’d seen the compressor kick on while filling the first can of freon. I’m a little suspicious I may have some other issues in the system (maybe the entire compressor). Are these systems very sensitive to having a full charge (525g) before the system starts to work, or do you think I may have other issues like I suspect? My previous symptoms were intermittent cooling and then the system stopped working at all. Thanks for any advice on my questions.

Mine was spinning as soon as I powered on. After the vacuum I put in what ever amount will go. I believe a couple oz. Then I go round and apply power and keep adding, I weight mine in at 18oz and its only -+1oz.

I dont even look at the pressures cause the low side is being controlled by the valve and the pressures arent reflective of what is going on in the system. I occasionally look at the high side when I start getting close to 18oz.

Usually pressures balance out and equalize when the compressor/system is off. low side is pretty steady at ~35psi and doesnt vary much because the FCV has control and is constantly moving very fast when the system is working.

I would suggest if you are not weighing in TO definitely monitor the high side, cause it only takes a wee bit of overcharge to spike the high side and you can get into trouble real quick. Not enough and you wont get the pressures needed for an efficient working system.

FWIW I just did my wifes car and after adding the special oil, it can get to 38. it gets to 50s in under a minute with ambient in 90s. It takes just a hair over 2 minutes to hit 42 degrees on mid 90s day. This is the best this system has worked ever, and is the best AC vehicle in my stable. But I do have other mods to the AC here in Texas, I have Windshield film and extra cabin insulation.

Hope some of this helps

Thanks Mach1. That helps a bit, but it still sounds like my system should have started to work some with the addition of the first can 12oz. I hate to add the second can if there is another problem as I suspect. How do I check and verify what else may be going on with my system? I can probably get access to a Vag-Com if needed. Thanks.

Ok if you only replaced the valve and the system worked kinda before, check the obvious like(dont get me wrong, i dont know your mechanical abilities and we need to start from scratch) the connector to the valve, is it making good contact? I have seen some of these had a bad connection to the plastic hood.

It sounds like you have plenty in there to get it going, another easy check is the high pressure switch which I believe a few people have seen bad before. reach under there and crank the compressor by hand just to make sure it turns with car engine off.

Did you use the super duper refer oil? did you add any other oil? there should be enough freon to activate the system. balance out at 100-105psi is good pressures is about right.

Mach1. I rechecked the connection at the compressor and all is connected securely. I swapped the high pressure valve with a used one that I'm pretty sure is good with no change. When adding the first can of R134A, I did also add ~3ml of Pag 46 oil to cover some lost during the RCV swap. Still no change in pressures as stated before "low and high reading seem to remain the same around 105-110 at an ambient temperature of 90 degrees".

I did get the VCDS and ran the auto scan, checked some HVAC readings and tested the fans. If anyone knows other tests or readings to check, please let me know. I was able to get both fans running with the VCDS and will post the scan results below: (I can post the full auto scan if needed)

Saturday,08,August,2020,09:19:13:29852
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 7 x64
VCDS Version: 20.4.2.0 (x64)
Data version: 20200730 DS317.0
www.Ross-Tech.com

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Address 08: Auto HVAC Labels: 1K0-907-044.lbl
Part No: 1K0 907 044 BE
Component: ClimatronicPQ35 090 0808
Shop #: WSC 00000 000 00000
VCID: 6BFB12BD4AF16CDED6-803E

1 Fault Found:
00229 - Refrigerant Pressure
002 - Lower Limit Exceeded - Intermittent

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Address 08: Auto HVAC (1K0 907 044 BE)

09:19:05
0.0 Compressor Shut-Off Code
800 /min Engine Speed
04:00 Standing Time
0.820 A Compressor Current (actual)
0.820 A Compressor Current (specified)
1000 /min Compressor Rotations
1.6 Nm Compressor Load
5.8 bar Refrigerant Pressure
9.6 % Radiator Fan Activation (actual)
0.0 % Radiator Fan Activation (spec.)

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That fault code is saying something there, I havent followed the fault codes very well. I would check voltage to compressor plug with AC on and see if its trying to energize.

Could be bad FCV?