Insects love warm electrical components and air conditioners are full of them. If you want to keep insects out, experts say do not use insecticides, because the electrical components will not like them. One option is to get a special cover for your relay switch, but be aware that it has to be installed by an air conditioning technician. The cheapest (and easiest) way to keep them away is to use a flea collar. To install the flea collar, shut the power off to the air conditioner and simply placed the collar near the relay switch.
When using latex be sure that the temperature is above 50 degrees F. It is difficult for latex to form a film at lower temperatures. With solvent-borne paint, be sure the temperature is at least 5 degrees above the dew point. If it isn’t, water may condense on the surface as it cools while the solvent evaporates, causing an uneven blushing effect.