I have 2 Mitsubishi mini split units on the 2 additions on my house. One is a Mr. Slim Inverter and the other is an Inverter.
During the warmer months when I am running them in A/C mode, they frequently give off a pungent sour milk smell. It seems to be when it is particularly humid outside. Here's what I've tried to fix the smell.
- Cleaning the removable/reusable blue plastic air filter
- Pouring a cup of white vinegar over the evaporator coil
- Pouring a cup of bleach over the evaporator coil
- Spraying the evaporator coil with Nu Calgon Evap Cleaner
- Removing an cleaning the blower wheel, drain pan and all surrounding plastic with the Nu Calgon cleaner.
These all seemed to help at first but the smell always comes back, sometimes within days. It is worth noting that the evaporator coil doesn't look particularly dirty. The drain pan was a bit funky and seemed to have a good bit of water but I checked and the drain is clearly allowing water to flow through to the outside.
Any ideas? The smell is very unpleasant and doing a number on our sinuses.