300TE A/C pressures (r134a)

[ps2cho]

I had an issue where the A/C would not turn on for the past few days...really odd....checked pressures today, first step in all issues.

Do these look right for r134a?

Outside temperature today is 57F. This was at idle ~700rpm. First pic is static pressure of course.
What is the correct static pressure for a W124?





If the issue returns, where should be the first place I look? Klima relay maybe?

[duxthe1]

Static pressure really isn't an indicator of anything except the vapor pressure of the gas in question. That said it appears you are low. For 134A I'd want a low side between 30 to 40 psi and a high side of 200-250 psi. ANywhere in that area should cool well.

[Matt L]

It is almost (but not quite) pointless to check the AC pressures at 57F ambient.

Look at the outside-most scale on your low-side gauge. Isn't that labelled "R-134a" and "*C"? Look at the reported temperature. Static pressure looks good to me.

[jcyuhn]

What Matt said.

Both static and running pressures look OK for 57 degrees. You're not going to see a higher high side at that temperature because the ac system is not removing any meaningful amount of heat from the interior of the car. That heat gain in the evaporator is what increases the high side pressure (and cools the car, BTW).

About all you can tell is the ac compressor is indeed operating.

[ps2cho]

Originally Posted by jcyuhn

What Matt said.

Both static and running pressures look OK for 57 degrees. You're not going to see a higher high side at that temperature because the ac system is not removing any meaningful amount of heat from the interior of the car. That heat gain in the evaporator is what increases the high side pressure (and cools the car, BTW).

About all you can tell is the ac compressor is indeed operating.

It is pretty cold here in Arizona right now...I'll wait for a day when it is above 80-90F and check pressures then and report back.

Thanks guys