Lack Of Carrier Central Ac Unit Information.

by Bill
(Byron, GA)

In 2005 I contracted to have a 2907 SQ FT Home built in Byron,GA. I wanted a super efficient home and had the outside wall all covered with OSB, then covered with 3R board, and then house wrapped. The walls and ceiling are insulated with Cellulose. I had previously built this same home in Gray, Ga.

I used a Rudd 4 ton central air units in it. It worked fine until the Temp. dropped below 20 Deg. or went above 95 Deg., then it would not maintain the house temp at 68 Deg or 79 Deg.. The average total electric bill was about $73.00.
I had specified a 5 ton central air conditioner for the new house.

The Trane dealer, Pro_Air, convinced the builder and myself to install a 4 ton Carrier high efficiency central Zone system made by Carrier. Model # ZONECC(2,4,8,)KitB. Model #???. The outside compressor unit is TRANE XL141. Model #4TWX4048B1000AA, Serial #53758P71F. Manufactured in 2005.

When the cold weather arrived the central air conditioning unit would not maintain the house at 68, and runs constantly at night. I called Pro-Air a lot, especially on cold nights. One Tech would come out and say the Freon was low, and then another Tech would come out and say there was too much Freon in the central air conditioning units.

Then on August 9, 2010 the power consumption suddenly jumped to 60 _ 72 KW a day from 45 KW a day. I called PRO-Air and a Tech. was sent out on the 11th. He said that the super heat was not within Spec. and the Expansion Valve would have to be replaced.

The Expansion Valve was replaced on Friday, August 13. I monitored the HPT and the LPT on the 16th and the power consumption was 27KW, with the house set to 70 Deg.

With outside Temp. of around 92 Deg. The HPT was running around 53, and the LAT around 58. Which looked good, and I called PRO_AIRr to tell them it looked fixed. The house TEMP. was reset to 77.

On August, 19 at 12:17 the HPT jumped to 65 and the LAT to 70. The power consumption jumped to 39 and then into the 50,s The outside temp. remained in the 90's.

I called Pro-Air and was told someone would come out Friday, August 20, between 12 to 3pm. The tech called around 7PM after I was gone.

My problem is that I do not know which readings of the HPT and the LAT are correct. Are they supposed to be in the (HPT)50's and (LAT)60's with an outside Temp in the 90's, and the house set to 77 or are they supposed to be in the (HPT)66, (LAT) high 60's to above (LAT) 70. I was told by a Carrier Tech yesterday that the Coil should be running in the 40, which would lead me to believe the (HPT) 50's and low (LAT)60's readings are correct.

Can someone tell me what the NORMAL HPT and LAT readings are? Then, maybe, I can stop calling PRO_AIR every time my power consumption JUMPS.