The AC system can be given an initial charge without the compressor being engaged. This is a common procedure especially if the system has a low pressure (binary) switch. The low pressure switch will not allow the compressor to engage unless there is some refrigerant pressure in the system.

I don't do A/C everyday. It is not my trade but I have done enough to know what I am talking. I would doubt any professionals would charge the system to the 'correct' pressure, as per the OP, without the compressor running/engaging.

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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

You are correct, I also seriously doubt that the system was charged to the correct pressure without the compressor engaging. I too, would look for a new mechanic. Unfortunately, I have done a lot of AC work, and have needed to minimally pressurize the system in order for the low pressure switch to allow the compressor to engage. The danger in not doing so and getting the compressor to engage by jumping the low pressure switch without refrigerant in the system is that quite often the refrigerant also contains compressor oil to lubricate the compressor (more often than not the compressor is pre- filled with the proper amount of oil - but you never know). As I explained I am not familiar with his car and therefore suggested several possibilities including the low pressure switch, a fuse, or if so equipped, the Klima relay.

Is the EC lamp lit on the panel?

You said the pulley was noisy - you can just buy the pulley/clutch assembly and swap it out on your old one.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

Thanks for all the replies. The mechanic who did the job is not shady, he is a friend of mine. He mostly works on big trucks but he gives me a really good deal on labor so I use him. I probably explained his initial charge procedure incorrectly. He did claim that the next day the compressor started right up and it has worked perfectly ever since. He told me he thinks the sensor needed to acclimate over night. I think he was to embarrassed to admit the ec button was on

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2006 E320CDI- current dd
1999 E300TD - retired
Wilmington, NC USA