Condenser and air handler question

I have a 1840sf ranch home all brick that is 12 years old. It had a 3-1/2 ton unit that worked. I had a HVAC company quote and install a York 4 ton 17 seer modulating condenser model HMH72B481. They also installed a 5 ton York air handler AVC60DX21. In heat mode the unit runs for 5-6 minutes than the fan goes into a very low speed mode for 8-10 minutes before shutting down than restarts 8-10 minutes later. When running the sound out of the vents are extremely noisy and where the air return is, the sucking noise is very noisy as well. Room temperatures are not consistant and I'm worried about moisture and possibly mold. I believe that everything they did is oversized. They HVAC company said everything is fine. Any comments?

 

Welcome to the forums.

Where do you live ?

Based on A/C only I would expect a 3 - 31/2 ton system.
Heat pumps are sized a little differently.

Did your installer do the calculations for system size ?
I'm guessing since it's a ranch the air handler is in closet ?

 

I live in Athens AL, 35613. As far as I know he said he estimated my system needed to be 3.4 ton but said going to the 4 ton system would not be a problem. Obviously I think it now is.The air handler is in the attic above the garage. As far as insulation the home is very well insulated. Windows and doors are all fully caulked. We even have those foam covers under all the outlet plates. Attic insulation is about 15-20".

 

The wall plate insulators are inconsequential. The attic insulation is part of the loss computation.
The air handler in the attic over the garage should not be noisy in the house.
I am very surprised that a heat pump system would be noisy in heating mode.
That should be a low speed blower.

Have you brought these concerns to your installer ?

 

The airflow on the 5 ton air handler would need to be configured to deliver the airflow for a 4 ton outdoor unit.