Warrantydrier, and approved a/c system flush or a work order showing the purchase of these items and that the system was flushed using approved procedures., heavy duty, or fleet use of compressors. important notice regarding a/c compressor warranty: in order to ensure that proper warranty credit is issued if needed, the compressor installation instructions must be adhered to. all compressor defects must show proof of purchase of an orifice tube/expansion valve,000 mile warranty on compressors. four seasons offers a 12 month / 12,000 mile warranty on heater cores and fan clutches. four seasons offers a 120 day warranty on all other parts. four seasons offers a 12 month warranty on commercial,four seasons offers a 2 year / 24