help please

[npp230v]

im new to refegiration passed all courses and now its time to start learning one question i kept asking but could not get a answer to is
IS THERE A WAY OF SEEING IF A AIR CON / REF SYSTEM IS UNDER / OVER CHARGED

EXAMPLE CAR AIR CON SYSTEM 134A
LOW SIDE /VACUME PRESURE IS 3BAR HIGH SIDE IS 15BAR IS IT OVER / UNDER CHARGED OR do you have to remove and recharge can any one help ?

[npp230v]

sorry using gauges alone

[The Viking]

im new to refegiration passed all courses and now its time to start learning one question i kept asking but could not get a answer to is
IS THERE A WAY OF SEEING IF A AIR CON / REF SYSTEM IS UNDER / OVER CHARGED

EXAMPLE CAR AIR CON SYSTEM 134A
LOW SIDE /VACUME PRESURE IS 3BAR HIGH SIDE IS 15BAR IS IT OVER / UNDER CHARGED OR do you have to remove and recharge can any one help ?

sorry using gauges alone

Short answer, No, sorry..

[The Viking]

The only way to measure if a system got the correct charge is to measure the sub-cooling. (or look in a sight-glass, if fitted)

[Brian_UK]

Car Aircon, recover existing charge and weigh in correct charge of refrigerant.

Cost of time and effort to fiddle about with temperatures and airflows is not worth it.

Do the recharge.

[monkey spanners]

Also it would need pressure testing to prove it was not leaking before adding any refrigerant.

[npp230v]

thats what i thought many thanks guys

[tez jags]

as a guide mate if you lick your finger and touch the suction line , if your finger sticks to it , its prob over charged .

[philfridge]

3 Bar suction pressure 15 bar head on R134a wow That system is overcharged for sure !