A/C question

[be12hunt]

I’m heading to help some family friends out that are in a bind. Long story short I’ve got some old a/c experience back in high school but never really learned the true way to properly charge a unit. Back then we just waited until the suction was beer can cold and we had a good delta t.
I would like to set these people up right until they have the money to get their stuff replaced.
So my question is what should I look for to properly charge their unit. If it helps I have a good understanding of superheat and sub-cooling, but only have a set of gauges and thermometer.

[thegrouse]

Go by the charging chart for the individual unit if the system is properly matched. Depending on the setup you may either charge to superheat or sub cooling. If it is a mix matched system I charge to Delta T and decent looking pressures for ambient temp.

[be12hunt]

Go by the charging chart for the individual unit if the system is properly matched. Depending on the setup you may either charge to superheat or sub cooling. If it is a mix matched system I charge to Delta T and decent looking pressures for ambient temp.

Thanks for this info. Are the charging charts something I can download? I’ve seen the old slide charts but that was 15 years ago.
What would be considered good pressures for ambient temperature(68-72 around here today)?

[MadHatter]

What kind of unit? Which refrigerant? Probably going to need a vacuum pump, and scales. Some people just go off gages, but that can cause problems, for things like mini-splits.

[thegrouse]

Thanks for this info. Are the charging charts something I can download? I’ve seen the old slide charts but that was 15 years ago.
What would be considered good pressures for ambient temperature(68-72 around here today)?

Generally they are in the unit near the schematic. I don't have a set of gauges handy but IIRC 20-30 degrees above ambient converted to pressure on R22 systems depending on high or low efficiency. I have not messed with newer refrigerants. This will all be dependent on coils being clean etc...

[JGlock30]

charging chart is usually on the inside of the panel you remove on the condensing unit to access the capacitor