Mini-split deep cleaning

lkhelp · August 18

Hello,

We moved into a house with mini-splits (Fujitsu, one outdoor unit, two heads inside) four years ago, have been happy with them, however few weeks ago one of them started smelling very bad - musty/moldy. I washed the filters - it seemed to help a tiny bit, but then smell came back. Called around few heat pump companies, but they all seem to focus on standard cleaning/vacuuming and want a hundred bucks to just come out and diagnose.
I stumbled on this bag/hose contraption that people seem to use to do a deep cleaning. Two questions:

Is it safe? Spraying liquids into electronics?
What cleaning supplies should be used?

Thank you very much in advance! This forum has been very helpful.

pecmsg · August 18

NO, It's not safe spraying electronics with chemicals.

Shut the system Down

Mild cleaners only

If the squirrel cage fan is caked, it will require removing. Not an easy task, especially reinstalling it.

Pricings not allowed but it's going to be much more then that if or when something goes wrong.

HVACNUT · August 18

I've used that kit a few times. It's a PITA and not completely water tight. And as mentioned, you still can't clean the fan properly without removing it. Even with a pump sprayer.

Greening · August 19

We needed to clean our split systems annually (for odors) when living in hot and humid cities.

The techs did this with similar disposable bags and other tools.

My brother tried did this on one Mitsubuishi head last week; it was difficult, time consuming, and messy. Hire this out to a pro who can whizz through the cleaning.

I think there was a gentle "rinse-less" coil spray sold in Asia but that never took away the moldy smells for us. Maybe using it frequently would.

Note that coil sprays typically require a lot of rinsing else they eat away the fins. We used these on outdoor units and it took forever to rinse out the coils. I don't think they are used for indoor splits.

DJDrew · August 19

I have learned to deep clean the units in our house, but it's a risk as there are a lot of plastic parts to break.

I have found most of the coil cleaners do a good job with the coils, but the fan blade needs to be completely removed and cleaned out in the yard to really remove the gunk. While the fan blade is removed, the rest of the unit is easy to clean up. It's just a lot of disassembly/assembly.

fastd · August 22

These heat pump units look great: the wave of the future and all, but they sure as hell aren't made to be serviced. They're a nightmare to service, particularly the indoor air handlers. Poor engineering from where I sit: designed by people who never had tools in their hands. I've also seen what I would call "planned obsolescence". After a couple of years replacement parts have been "upgraded" and no longer work properly, or at all. Just my turn to vent is all, lol.

ChrisJ · August 22

https://forum.heatinghelp.com/discussion/comment/1808606#Comment_1808606

My main complaint here is calling them "heat pump units"

They're minisplits. The heat pump function isn't part of their platform or design.

But yeah, attempting to clean them is a bit ridiculous. No, actually it's very ridiculous and to try and do it right you risk breaking stuff even if you know what you're doing and are good at it. It's a big part of why I went with a ducted normal split in my own home. 1 evaporator to deal with and a pleated MERV 8 filter with gaskets makes it so I don't even have to consider cleaning it. Perhaps they need to come up with substantially better filters for the minisplits but then that limp super quiet centrifugal blower they use won't work.

While I'm at it, standard splits aren't great either in this regard. Thin sheetmetal with self tapping screws that strip out the 2nd or third time you put them in, how are you supposed to tear that stuff apart and clean it? Especially outdoor units with really fine condensers that trap all of the dust, pollen, lint etc? They need to do better across the board………….

All of that said, I still feel the mini splits have their uses and am using a few my self. Just not in my home.

pecmsg · August 22

https://forum.heatinghelp.com/discussion/comment/1808611#Comment_1808611

no they need to be sized properly.
units that run 3/4 - full speed do not get the growth build up.

ChrisJ · August 22

https://forum.heatinghelp.com/discussion/comment/1808625#Comment_1808625

Ours at the shop seems to blow a bunch of it out when it runs on high.

I can't remember if that happens in cool, or heat mode but it does happen. I haven't pulled the fan out on it in 4 years now, so I guess it's getting by and keeps it self clean, enough, but I've seen some pretty scary pictures of units online.

The only detail I remember on this unit is the first time I switch to heat mode I get steam. Other than that it sits in the back round doing it's thing 365 days a year.

bruin64 · August 23

I have had a mini split for 11years now. Mitsubishi with two indoor heads. First found a caked fan when it started making a noise after4-5 years. Called the installer he showed me how to take them apart and clean. Each head gets a cleaning every other year. I remove the fans and hit every mold spot. I think mold can be minimized if you run the heat to dry out the coils at the end of summer. No good having them sit there loaded with moisture. Local environment seems to drive how skanky the units might become. I live on cape cod lots of damp and wooded areas. The heads need better design for service they need to come apart more easily. Real filters needed too.

Big Ed_4 · August 24

The through wall needs to be sealed off on installation ……

Mini-split deep cleaning

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