I've been complaining about my 4 ton Carrier Infinity (24ANA748 condenser, Infinity thermostat) for years. Basic complaint - its just doesn't seem as cold as the old Goodman R22 system that it replaced, but I don't have any facts to back that up - I didn't obsess over the old system, it seemed to work fine, until I had to have it replaced.
I've had a couple of different companies come out, but I guess I'm being stubborn.
Had someone come out yesterday on a good hot day, and I asked for a good check and that I wanted to record the numbers.
Outdoor dry bulb: 92.7F
Outdoor humidity: 55%
Evaporator return air temp: 79F
Evaporator supply air temp: 65F
Indoor wet bulb: 64F
Indoor humidity: 53%
Suction Pressure: 158psig
Hi side Pressure: 360psig
Suction Line Temp: 71F
Liquid Line Temp: 94F
Vapor Line Temp at the outlet of the evaporator: 66.5F
1400 CFM (from the infinity Thermostat)
Blower RPM: 1400 (from the Infinity thermostat)
Static Pressure: .77 (from the Infinity thermostat)
Required subcooling for this unit: 15F
Calcuations based on figures above:
Superheat (system): 16F
Superheat(at the evap): 10F
He took evaporator return/supply air temps near the air handler.
So, as usual, he said everything is right on, but I can't understand the following:
1) I guess that evaporator delta T is OK based on what he told me and from what I've read, but my downstairs R22 system sure does better
2) That liquid line temp has always been at or just above outdoor ambient. This is subjective, but it just bugs me that when I reach over and "feel" the suction and liquid lines on my R22 condenser (downstairs unit), the liquid line is very warm and the vapor line is very cold (and sweating much more than the Carrier). Is that just a function of R22 vs R410a.
3) Lastly should they be measuring air flow instead of just looking at the Infinity thermostat? I don't think I've ever seen anyone take a CFM measurement. More than one has said that the Carrier Inifinity adjusts blower RPM to maintain proper CFM.
4) I've been told that these high efficiency units are designed that way (not as cold), but that just doesn't make sense either.
Bottom line, if they are getting good subcooling and superheat values, is that the best I'll get out of this thing?