There is exceptions to every rule but generally the systems are set up to run only one pump with the second as backup.
Originally Posted by archibaldtuttle
Ran into a retro-fitted compressor [4 ton capacity] on a 2 ton Carrier RTU today that exhibited similar symptoms as were mentioned here.
Fixed orifice [I believe]
63 lbs back pressure, suction line @ saturation. 350 lbs head with 12 degree's sub cool. 75 degree space 80 degree OAT. Cleaned evap/condenser/Indoor blower with nitrogen before calling in the numbers.
Having a terrible time grasping the science on this one, with a fixed orifice.