I had a call yesterday on a cooling problem. The first thing I noticed was that the condenser was extremely dirty. It was an Allegiance 12 model number 2A7A2048A1000A (for those who care), R22 system.
After cleaning the outdoor coil I took some pressure/temperature readings:
Ambient 95 degrees
Discharge psi=298/131 degree saturation temp
Suction psi=55/30 degree saturation temp
Super heat= 12 degrees
TXV metering device
That is as far a I got before the storm hit, my initial evaluations based on pressures alone would be low charge. However, with sub-cooling at 17 degrees that changed that thought. Just to verify the condition of the evaporator I measured superheat to ensure that the TXV wasn't starving it.
My course of action this afternoon is to look at air flow across the evaporator (low heat load). I plan on looking at the coil, filters, blower, delta T, and FLA of the IBM. If I am properly charged and both the suction and discharge pressures are low this should mean that I have a low heat load across the evaporator.
I would be interested in your thoughts on this matter.