I am getting quotes for a new R410A condenser unit/evaporator coil from several HVAC contractors. A salesperson refused to give me a quote unless I purchase a new furnace as well. He said that he has seen problems using a new evaporator coil on top of an older furnace. My furnace is an old natural gas Trane furnace from the mid 80's. My current evap/condenser is about 7 years old.
I live in south Texas, so the furnace isn't really used enough to justify replacing it if I don't have to. I had it checked out when I bought the house about 4 years ago and it passed a health check. Is there any truth to what this salesperson is telling me? Are there any issues that can arise from using an old furnace with a new coil?