We found mildew buildup on the evaporator coil inside the heat pump water heater, caused by a lack of routine cleaning. We recommended a full coil cleaning to restore proper operation and improve system efficiency and air quality. • Disconnected power to the hybrid water heater at both the breaker and the external disconnect, then removed the top cover of the unit. • Applied coil cleaner to the evaporator coil to break down mildew buildup, then scrubbed remaining deposits with a brush for a deeper clean. • Rinsed the coil with warm water to remove all residue and placed a drain pan tablet to help reduce future mildew growth. • Tested the condensate drain line and confirmed proper flow with no blockages. • Reinstalled the top cover and restored power to the unit. After restarting, the unit displayed an error code indicating a clogged condensate line. I explained to the homeowner that this occurred because the drain pan sensor was temporarily activated by water used during cleaning
