Chris immediately diagnosed and fixed the problem that made the new register vent cover hang loosely and dangerously. He explained to me that the problem had to do with the "flange" on the ductwork leading to the register cover, so he had to move the ductwork to get at it. (A worker from a previous company had been unable to find and fix the problem.) Chris also checked all of the other new register covers and showed me how to adjust them and how to remove the covers to replace the batteries on the new smoke alarms, all without making me feel like an idiot. He is the most polite technician I have ever encountered!
