I have used Frymire Services for warranty and planned service on my HVACs since 1985. Frymire installed the equipment when our current house was built in 1995. They send a very well trained and courteous technician each 6 months to inspect and do preventive maintenance on my systems.
Recently, an electric part burned out and I had to call for repair. I called after hours and my system was repaired next day by a skilled tech who listened to my description of the problem and went directly to the part needing replacement.
I wish all service companies were like Frymire.