Customer recently replaced the air filters for each unit. I checked the electrical wiring and electrical systems, including the auxiliary heat strips and all are within specification. I operated the units on second stage heating mode and measured heat of extraction for each unit which is right at 50,000 btu/hr which is slightly better than printed data. I pressurized each ground loop to 65psi. Both units are operating normal. I gave the customer an estimate to install a humidifier on unit #2, which serves the downstairs area. I also noticed that neither electrical panel has any form of surge protection and highly recommended adding whole house surge protectors to each of the 2 main electrical panels.