normal a/c pressures

[guse1096]

I have 93 mtx with r12 refridgerant...clutch seems to cycle frequently (every 5 seconds+ -)low 26 high 170 when cutout happens.I have a new pressure cut out switch installed. Wondering if this is normal operation or if it is incorrectly charged? Temp was 80F when tested and engine was idling...ice cold out of vents. Compressor pulls down on motor causing annoying surging

 

[rubydist]

iirc, the low pressure cutout is somewhere around 30, so that is likely why its turning off. at 80f, the low side pressure should be around 45 psi, so it needs some gas.

 

[projectSHO89]

Compressor short-cycling is almost always due to a low charge regardless of the refrigerant in use.