High Coil Temp for Trane 1.5 Ton

[cotsy]

This is for a 1.5 ton Trane 16 SEER Condenser 4TTR6018J1000A Air Handler TEM4A0B18S21SA. Everything looks OK except the evap coil pressure seems high at 141 psi (49 deg F). Delta T air is about 16 deg. Not bad but it seems like it should be a little higher?. R410,
Outside - head pres 321, Suction press - 141, Suction temp -67, Subcool - 9 deg. (8 spec) Liquid line temp - 92, Outdoor temp - 83, Superheat - 18 deg
Indoor - Rtn air - 74 deg, Rtn RH - 52%, Supply 58 deg, Supply RH - 80%. Ext static press is 0.44in WC. Fan is set to low. Trane chart with this press and tap shows airflow should be 610 CFM.
I measured the suction line temp for 3 homes AC near me and they are from 45-55 deg (vs my 67 deg). I also measured the BTU output (measured enthalpy in and out of air handler) and it is low, 13,000 BTU/hr.
Thanks

[Admin]

I wouldn't be too concerned with that suction pressure.  Excessive load and high ambient can do that.  Under certain conditions the suction line can run warmer.

Depending on the indoor wet bulb you could be slightly undercharged, but I believe that coil uses a TXV and if the sub-cooling is correct then there's likely no issue with the charge.

You could try to increase the indoor airflow to 800 CFM and see if that improves the AC's performance but it could also lower the comfort level by lowering the delta T.

Does the AC satisfy the thermostat and turn off on the hot days?  And what's the ambient indoor humidity?

How did you measure the enthalpy?

[cotsy]

Thanks for the response.
It does cool the space and shut down, but I think it was doing it much faster before.  I measured enthalpy with a UEi psychrometer. Indoor humdity was 52%.  I think the fact that the btu/hr total is below spec and suction is high shows there is an issue.  TXV?