Question on CAC A-coil

whats cac

Central air conditioning

How long did it run? It goes from one end to the other at first.

furnace with an A-coil mounted on top for CAC. I turned

I would say a good 20 minutes.

The coil should be uniformly cold with all measured air temps leaving the coil very close to the same. There may not be an evenly balanced airflow heatload distributed across the coil. Partially plugged distributor or coil circuits.

One of the most important things there is for optimal performance, is to always have an optimal heatload evenly distributed through the E-Coil. That is a first essential to accurate refrigerant charging of the system using Superheat or Subcooling for TXVs.

It's normal for the upper and lower to be a few degrees different. If part of the coil is room temp, you may be low on freon.

If it's cooling the house OK, don't worry about it. Otherwise, call a HVAC service company.

You may have to upgrade from CAC to EAC, or even FAC. The new energy standards are much higher. (grin here). I think they stopped selling BAC in 1994. (wink, wink).

Thanks for the info. You mentioned I might be low on freon. Would not that cause the coil to freeze up?

That depends on air flow, metering device, and some other factors. I've worked on a couple systems which were low on freon, and got cool at part of the coil, and room temp at part of the coil.