Mini Split Clean up

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peakbagger

Minister of Fire
Jul 11, 2008
6,486
Northern NH
I have a mystery odor in my house, My guess is a mouse found a spot and died but I noticed that the odor is more noticeable with the mini split in cool. Mini Splits are known to be occasional odor producers due to build up of mildew and bacteria in the internal drip tray and few realize that they are supposed to be maintained on occasion. So I fired up You Tube and watched a few videos on the process. There are slight variations between models but the general approach is the same. Once two screws are removed everything is snap connectors. Its been together for quite awhile so getting things apart requires some careful prying and pulling. The condensate drip tray was a bit harder to remove than the videos show. The standard drain connection is on the right side (facing the unit). On my setup its on the left side. In the videos the tray is left attached on the right end and then tilted down hanging from the right side. With my set up the drain prevents it from tipping down. I would need to remove the drain hose. I did not but got enough free play to tip it down enough to get into it. One of the observations I have seen on many minisplits is the drain connection does not fully drain the drain tray, the water level has to build up until it can drain by gravity out the drain pipe. My install was right to the instructions but I suspect if I do another one I would increase the side of the pass through pipe through the wall and get the drain pipe right on the bottom of it. There is possibility that the partially full tray is deliberate as it would act as a trap from outdoor air coming in via the drain pipe?

As it was, I had a tray partially full of water with a layer of slime on the bottom. I blotted it out with paper towels and then cleaned it out with bleach based spray cleaner and they cleaned it out well. At this point I also could see into the blower. It didnt look bad but looking at the videos the next step to take it out is not that difficult. The other observation is that the coil piping closest to the tray had some corrosion so at some point it could fail and would be difficult to repair. I didnt have any no rinse spray on coil cleaner so I left the coil alone. It didnt look bad but I expect I will get some for a future cleaning. I expect in a house with a low mounted unit, pets or a construction trailer with a lot of dirt that cleaning coils would be needed.

Before reassembling the case I took it outside with some household spray cleaner and hose and cleaned everything off real well.

I will continue to look for the mystery odor but I am glad I gave the unit at least a partial cleaning. The biggest risk is the plastic getting brittle.
 

Woodspliter

Member
Jan 25, 2020
131
Maine
That's a good write up, I have to give mine a good clean at the end of the season. I keep up on the filters but haven't gave the coil a good cleaning. I bought the kit just haven't put it to use yet
 

Bad LP

Minister of Fire
Nov 28, 2014
1,732
Northern Maine
I use a coil cleaner that works as a disinfectant just for that purpose. Leaves a minty fresh smell. LOL
 

Bad LP

Minister of Fire
Nov 28, 2014
1,732
Northern Maine
Stuff I use is Virginia Coil Klean Coil Cleaning Foam. No rinsing required. Works on both the condenser and the evaporator but outdoors I use Pro Brown Coil Cleaner thru the mixing nozzle. It washes out all the pollen and dirt that gets sucked into the coil.
 

peakbagger

Minister of Fire
Jul 11, 2008
6,486
Northern NH
The scary part is the corroded spot on the tubing. At least one of the videos mention the same corroded area.
 

maple1

Minister of Fire
Sep 15, 2011
10,796
Nova Scotia
You can get little tablets to set in the tray, that are supposed to prevent any growth of anything. And HVAC trade thing? My split guy was here last week and put a couple in ours - just something preventative they started doing last year. Mine are still looking as new, nothing growing or accumulating, even without the tablets until last week, after a year and a half +.