I’ve had bug problems for years with a mini split that was professionally installed about 12 years ago. The unit works fine, but I keep getting some sort of insects nesting in it, resulting in droppings all over my workbench every few days. The wall penetration looks to be well sealed, and I’ve installed a screen over the condensate drain. I’ve taken the unit apart, cleaned it out, and sprayed a heavy dose of insecticide in there, but they keep coming back. Suggestions? Commercial grade insecticide? I don’t want to pollute the air in my garage too much….race car exhaust does enough of that, but it dissipates quickly.
Insects in Mini-Split fan unit
- Thread starter m3bs
- Start date
rlitman
Well-known member
Are you sure they're in the unit and not in something else over your workbench? What sort of droppings are we talking about?
Definitely in the unit. Researching cockroach larvae, that looks like what I found inside the unit, and the droppings are consistent with cockroaches, although I haven’t seen any adults in the unit. I may try tossing a few boric acid tablets into the unit. That seems to help control them in the house. They are everywhere around here, so that is the most likely culprit.
fitter30
Well-known member
I've used this company for different problems their recommendations have worked.
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American Locomotive
Well-known member
I would not put any acid tablets in the unit. If it evaporates/off-gasses any acidic vapors, it will probably start eating the coil. If you have a screen over your condensate drain, and you're 100% sure the wall penetration is sealed - they're likely coming in from somewhere else and just setting up shop in the unit.
rlitman
Well-known member
Agreed. You don't want to start corrosion like that. But you can get algacide pan tablets that will dissolve in water in the condensate pan, and while they're not super toxic to insects, they might help. You could also use something like a fipronil gel. That should work wonders on roaches compared to boric acid.
pcmeiners
Well-known member
To add, insect are bad enough but mice/chipmunks will get to the control boards. I purchased some copper wool off eBay and stuffed the area covering the King valves and wiring tight so they do not have access at that point. It may or may not stop them depending on your mini split design. Agreed using Boric acid, or anything with either a low or high PH is a bad idea. Fipronil (Termador) is a good idea for insects coming from a nest, it will kill the entire nest, but takes a couple weeks...you only need a tiny amount so it will not harm the coil or anything else in a mini. Could be termites going to the evaporator for a drink. Perhaps an insecticide that is powder or granular, placed in a glass dish in the unit