We have a Trane furnace/AC + Aprilaire humidifier. These were installed together about 3 years ago. We have a yearly maintenance contract with the company that installed them and so they come twice a year to check the system. Had a check up today and the tech said the humidifier is broken. More specifically, the humidistat controller is (Aprilaire 884021BS). He offer to replace it for a "reduced" price (parts + labor) of $250. Reduced? Sounds steep to me! I said I'd think about it. If it's only the humidistat, $250 seems to be a bit steep, no? So I am trying to figure out how hard it would be to test and, if needed, replace the humidistat myself. 1. How should I test the humidistat to verify it's indeed bad? 2. How hard is it for someone without any HVAC training who only has experience fixing small things around the house to replace it if it's indeed busted? 3. Less than 3 years for a humidistat seems too short. Should I look for a different brand of the controller, given that I don't want to replace the whole humidifier which is Aprilaire? Thx! UPDATE: Contacted Aprilaire and was referred to this as the replacement.