Checked in with customer. Upon Diagnoistic of the 18 year old 5 ton Lennox unit, I can't condenm any component failures at this time. However I find the compressor the cusp of over amping. It's rated factory maximum amp draw 25 amp actual test reading 23.9A. The system is working at it's full potential. I can not improve or enhance the performance of the system. Recommend replacing 5 ton Lennox unit due to age and efficiency. Will have office quote customer.