What would make my mobile home unit freez up. I had the outside unit replaced
With a 13 seer 5 ton .the duct work was uped from 12 to 14 feeding the other side of double wide mobile home. It was raining and about 65degrees and it froze up what could be wrong

My outside unit would freeze up when it got humid out during the night. It was a relay that went bad in the unit. I would have to "defrost" the outside coils by turning off the unit and waiting for it to thaw out. Every time the thing would freeze up the relay switch was always the culprit.

Dirty air filter

Incorrect refrigerant charge

Lack of proper duct size.

A 5 ton unit needs to move a lot of air.

I agree with hvac1000. A dirty evaporator coil or filter is the most common. If you can't move the air due to a restriction in supply duct or return air it will freeze up every time. 5 tons is a lot of air for a mobile home system.