I have a good friend in lancater south carolina that im helping over the phone to install a new gas/ac gas pack ! He had a new one icp 3 ton / 100k installed 3 yrs ago and it caught fire . The hvac company that looked at it said they never saw anything like it and the wiring needed to be replace at a cost of 1000 dollars . So I helped him over the phone and he bought a new rheem 3 ton ( 12 seer - gas combo ) Hes on natural gas . The first thing he told me that didnt sound right was he had to reduce the fitting coming off the return of the unit to a 14 so it would fit to his flex ! I havnt got into the return size with him or how many suppys and what size . He got his new unit installed this week and I havnt got into all the details about register and flex sizing yet . Since im in ohio im going to suggest he hires a hvac company to look over the install and check the gas pressure and make some recommdations on his ductwork . Who can give me an ideal of where to start with this project . Thanks in advance for all he help . BH