Is my a/c over charged?

Question

just had new cond. installed. it makes a little noise when it starts up. here are some parameters. outside air is 86 deg. - low side press. 66 psi.- high side 182 psi. -suction line temp(close to valve)42 deg.- return air temp 76 deg.- vent in l/r temp 52 deg.. coils supper clean. great air flow. my question is. did they over charge the system. its r-22 by the way. could that be causing the noise upon start-up ?

Answer 1

Check your subcooling asap ! Head pressure converted to temp,then subtract the temp of the liquid line.Normal range is around 20 degrees and when it is real high,you know the condenser is flooded with liquid refrigerant and over charged.That's the fastest way to see if she's overcharged.She could be.

Answer 2

Those numbers appear to be within range. It might be a touch overcharged.

To be getting liquid back to the compressor your suction line temp would have to fall to 38 degrees or the low side pressure be up to 72 lbs at 42 degrees.  

Heat load affects your readings also. With a 24 degree drop it is running a little cold and/or your humidity is rather low (wet bulb temp).

http://www.longviewweb.com/pressure.htm

But it depends on how new it is. I doubt that the charge is the sound you are concerned about. For some reason the valves in some new compressors clatter when new on start up and that will likely diminish a lot.

It just might need a little time for break-in if it has not run much yet.

Good Luck.

Answer 3

the best and oldest way to test your theory is to let it run, your low side should be nice and sweaty and cold but no frost. A lot of systems have a loud start being as though they need the extra juice to get them started. good old fashion looking at your condensor looking for condensation and frost. if you have condensation (good) frost(bad)

Answer 4

You gave all the right numbers for the right answer!  The temp on the suction line is too cold, your TD 52-76 degrees to too big the evap coil might be dirty or and air flow problem Normal TD is around 18 split. 80 in the room and 62 out of the vents. When I check a/c systems and find a high TD I look at the coils, filters, and blower wheel to make sure they are clean. When they installed the condenser did they inspect the inside. Also just a hint for return air you need around 150square inches per ton. A 3ton system needs close to 450sq inches. The noise on start up is due to the compressor eating liquid refrigerant which it should not be doing.