What should the pressure readings be for a American Standard Freedom 500 2.5 ton air conditioner be
Hi, this depends on the outdoor air temperature and type of freon this unit has. The hotter it is outdoors, the higher the pressure will be as they use a pressure/temperature relationship. If the unit is R-22 and lets say it is 90* F. out side, the low side or suction side will be at around 68 to 72 p.s.i which would give you an evaporator temperature of 40* F. Head pressure would be at around 90* plus 27*= 245p.s.i. This is if the condenser fan is in good condition and the outdoor coil is clean. If you are using a set of manifold gauges you have the pressure/temperature scale right on it. If the unit has a TXV for metering, you would need to charge it using the subcooling method. On a Non-TXV you would use the superheat method. If you are using the new R-410a freon, the pressure are extremely high in these systems compared to the R-22 system, so make sure you look at the units data plate to read the type of freon. The color of the container is green for R-22 and a Pink for R-410a and the 410 a unit will display a pink warning sticker on the unit to tell you. The pressures on the R-410 would be at 90* F, low or suction side at that temp is around 125 p.s.i., and around 400 to 420 p.s.i. on the high side, much higher then the R-22. You would also need a manifold gauge set made just for the R-410a (AZ-20) as of the extreme pressures in the system. There is never a set pressure to go by as the outdoor temperature will raise and lower the pressure of freon very fast. If you are asking this question because you have a manifold set and are taking a reading, the unit has a charging method pasted right on it from the factory showing what pressure they want it to run at. Your gauges also can be used as a pressure temperature chart, or you can pick one up free of cost at a a/c parts house to keep with you. It will show you how to calculate the charge for your unit. If you are familar with pressures, this should be of a great help to you. I hope that I have helped you on getting the unit charged properly. Please keep me in mind when rating me, as I know you will be kind. Just drop by a wholesale a/c parts house, walk in and ask for a pressure temperature chart, and they will hand you a couple of them. They have very good information and no how on all of the most common freons in use today.
Best of luck
A/C, Heating, & Refrigeration Contractor
Jul 29, 2010 |
Heating & Cooling