I arrived for a 3 system heat maintenance inspection. Our client provided air filters to be replaced today. I proceeded to clean the flame sensors, pressure switch ports and furnace cabinets for all 3 units. I found the main upstairs and main downstairs units to have very dirty blower motors with dust accumulated on them. But all motors did test within manufacture specifications. I also tested and ensured all fire shutoffs were working properly. All tested passed todays inspection. The main downstairs unit had a compromised drain pan that should be replaced to prevent water damage in the ceiling of the home. I showed this to our client and she agreed it had been leaking water on the exterior of the home. We also discussed adding air purification to our clients units. We discussed bundling the air scrubbers for all 3 units in the home. All units are running properly on departure.