Sisters ac unit, is this normal or what?

[Old Man Kenneth]

she had a 3 ton 410 aruf goodman (not a hp) put in (meaning put in the central closet but not hooked up) this past february but wasnt charged up and running until her house was finished 2 weeks ago.

When the thermostat clicks to turn the unit on, the air handler sounds like there is something else fairly quiet starting inside it for maybe 2 seconds then the blower fan will start up. That normal or what could that be?

Then when the unit shuts off you can hear a gas hissing sound for maybe 5 seconds and the blower fan slowing down until it stops. That normal or what is that?

Other than that the unit cools and runs perfectly and is very quiet, 20-22 degree difference between what comes out the closest ceiling vent and what goes in the supply grill and strong air flow out the vents.

Told her i would post here for some opinions before she got the installing company out to ask the questions.

[beenthere]

Probably hearing the refrigerant starting to flow before the fan starts. And then equalize after the blower shuts off. Normal on many systems.

[Twilly]

Twilly says that is a good sound.

[skippedover]

There's a short delay before the blower comes on. That's normal with the Goodman air handler. The hissing at the end of the cycle is the normal movement of refrigerant through the system as the high and low side pressures begin to equalize. Refrigerant just likes to move a lot and will continue even with the system off, constantly migrating from warmer to cooler areas. You just don't hear it unless it's moving under high pressure, which it is at the end of a cycle.