You may be right on the cusp of recommended pressure. Not a guarantee, but when the pressure sensor detects pressure below the desired level it will disengage the compressor to prevent it from burning out, likewise I think it does the same if overpressured (maybe when hot you exceed the upper range)
pv=nrt.

I think you can check this from the W210 climate control by going into diagnostic mode, I have yet to try this but you need to press the reset button for 5 seconds while the key is position 1 or 2 prior to start up. Search the forum, I'm sure someone has posted the correct way to enter into this mode.

good luck

Mine has a leak and it's the big one, I read the diy and it's scary, too scary for me to attempt just yet.

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1991 190E 311K [Brilliant Silver/Black MBTEx] -retired
1996 E300 315K [Black/Grey MBTex]

Want to put a tank in the trunk for WVO/SVO in the E300 Need to find a place to store my OIL!
Still procrastinating about the biodiesel/WVO
Made some biodiesel but so afraid to pour it all in - I've added some and think I'll supplement my fuel to see how I make out

Made some biodiesel but the process scares me - methanol fumes are not your friend! Need to do this outside.