I used Ferratos because my father had used the previously for this unit. Tech came charged me 90.00 to tell me my unit was dead. The owner then came out and price a new unit for me $4500 to $6500. The unit is about 18 years old so I assumed it was time to change it. Before spending that kind of cash I decided to call in a second option (WF Han). That tech came out showed me where a DRAIN LINE WAS PLUGGED. He did a routine maintenance and I made a appointment for an annual maintenance the following year (400.00 total). The drain had been plugged for about 10 years (estimated). There is a good chance that the repairs Ferrato did the years before were not needed. (1000's of dollars worth). I was really angry. I sent an email to Ferrato explaining what I found and asking for the service fee back......no answer......avoid them like the plague.