W123 Diagnose Failed AC Low Pressure Switch - Page 2 - PeachParts Mercedes-Benz Forum

97 SL320 · #16 06-06-2019, 05:56 PM

Quote:

Originally Posted by tangofox007

One more time: the low side pressure has no effect on the low pressure cut-out switch.

How about for clarity typing: The insufficient static system pressure switch is located on the high pressure side of the AC system. This switch also performs a safety shutdown if the high side pressure exceeds a certain threshold.

gottarollwithit · #17 06-06-2019, 06:47 PM

Not quite sure where the high side port is.

Agreed, if the low pressure switch is on the high side, whatever is read on the low side isn’t a good diagnostic indicator.

I think the best thing to do is drain and rebuild the whole system..... or just run it the way it is til it breaks.

New question: With a low side pressure of 15 psi while running at 3k rpm, will this damage the compressor? As in, low pressure being insufficient to flow oil and refrigerant to protect the comp?

tangofox007 · #18 06-07-2019, 10:27 AM

Quote:

Originally Posted by 97 SL320

How about for clarity typing: The insufficient static system pressure switch is located on the high pressure side of the AC system. This switch also performs a safety shutdown if the high side pressure exceeds a certain threshold.

For accuracy, how about deleting everything in bold?

97 SL320 · #19 06-07-2019, 05:35 PM

Quote:

Originally Posted by tangofox007

For accuracy, how about deleting everything in bold?

From another persons post 9

Quote:

Sometimes being familiar with the car instead of generic GM knowledge is a useful thing. MB's of this era had no switch on the low/suction side. The switch was on the high side at the filter/drier. Early switches were low-pressure only to prevent operation if the system was out of gas, later ones (and modern replacements) were dual-function high/low switches to trip the system if head pressure got too high.