New Carrier straightcool

[dj3901783]

What do you guys think about a spilt carrier straight cool, that has been vac and micron gauged, with a weighed in charge put in, but only has a 10 degree split at the evap coil? Subcool was ~40 degrees with ~8 degrees superheat. I tried to purge the unit to lower the subcooling to 16 then to 10 then 6 degrees but has no effect on the temp. split. No restrictions in filter drier, so does it have to be the TXV or is there another option?

[udarrell]

You are not telling us what the actual pressures were.
I don't know how you could purge from 40-F to 6-F Subcooling. (?)

How much airflow do you have & how high is the humidity.
Could it be pulling hot moisture laden air from the attic into the return.

At 400-cfm per/ton of cooling, an 80-IDB & 74.5-IWB will produce around a 10-F SA/RA delta-T split. What were indoor conditions?

Maybe the airflow is 475 to well over 500-cfm per/ton of cooling, it can happen with wrong speed selections, & the new powerful & sometimes oversized air handlers.

[dj3901783]

Humidity is low as I am im phoenix, arizona. pressures were on the low side 53 degrees or ~135psig and 135 degrees on the high side or ~500psig. After I put some 410a into my recovery tank to get the subcooling down pressures were at 125/420 indoor was 81, outdoor was 118

[dash]

What model and serial number?

Might want to do a static pressure versus temperature test to see that the refrigerant is pure.

[dj3901783]

I thought the person who did the start up left nitrogen in the unit or ... so I pulled a good vac and weighed in my charge.. the right way or so I think.. both the condenser/coil are 6 months old... model number coil CNPVP6024ACAAAA, condenser 24ABA360A320, the unit next to it is identical.

[beenthere]

R410A at 135 PSIG has a sat temp of roughly 48°F.

Get all the readings, not just is was 135 psi suction line.
Also need all the temps.