Mice and Mini Split AC units.

   / Mice and Mini Split AC units. #1  

GLyford

Veteran Member
Joined
Feb 25, 2009
Messages
1,304
Location
MA
Mice got into our mini split outside compressor housing and trashed the wiring and insulation. I would not be surprised if the wiring has soy based insulation like many people complain about in their vehicles for similar reasons.

Harness is not available as a replacement part and the compressor motor may be damaged. Neither the warranty nor our insurance cover mouse damage, so we just have to soak up the cost of a whole new compressor unit.

So...what has worked for you to keep mice out of outside AC equipment? I am reluctant to use poison because our two dogs and there are neighborhood cats (not to mention hawks and foxes) but if it is the only thing that works then I will. To those who say "get a cat" there is a garden bench two yards away the neighbor's cats sun on to annoy my Aussie but there were still mice. Not many cats sunning at -10F.

There are large openings (about 1x2") on two sides, I was thinking I could start by covering those with metal bug screening or 1/4" hardware cloth or both, but since mice can already chew through wire...?

People have variously suggested moth balls, cotton soaked with peppermint oil, and dryer sheets. I understand these have mixed results at best. Ultrasonic repellers seem to be mostly about separating customers from their cash.

So...what has worked for you?
 
   / Mice and Mini Split AC units. #3  
I doubt that the compressor was damaged by the wires being chewed. Anyone with a little knowledge of air conditioning can rewire the unit without having to get a new harness. Any Home Depot or Lowes has mouse poison in little refillable containers that a dog or cat can not get into that can be placed around or in the unit. If the vent holes were covered with hardware cloth I don't believe that a mouse would go to the trouble of trying to chew through it to get in if he could not smell any food inside. They would probably head for your water heater vent instead.

My problem has been mud daubers that go through the vent holes and build large mud nests on the fan blade preventing it from turning during the off season. Hardware cloth is too large to keep them out so I have used window screen but I have to keep inspecting it to make sure it doesn't clog up and prevent adequate air flow through the condenser.
 
   / Mice and Mini Split AC units. #4  
I doubt that the compressor was damaged by the wires being chewed. Anyone with a little knowledge of air conditioning can rewire the unit without having to get a new harness. Any Home Depot or Lowes has mouse poison in little refillable containers that a dog or cat can not get into that can be placed around or in the unit. If the vent holes were covered with hardware cloth I don't believe that a mouse would go to the trouble of trying to chew through it to get in if he could not smell any food inside. They would probably head for your water heater vent instead.

My problem has been mud daubers that go through the vent holes and build large mud nests on the fan blade preventing it from turning during the off season. Hardware cloth is too large to keep them out so I have used window screen but I have to keep inspecting it to make sure it doesn't clog up and prevent adequate air flow through the condenser.
 
   / Mice and Mini Split AC units. #5  
You could mount the unit up on a metal sheet, then put the sheet up on legs at least a foot high. Mount the legs in from the edges about 6". Keep all flowers and shrubbery at least 2' from the unit.
 
   / Mice and Mini Split AC units. #6  
That was kinda wordy.....

guess I just could have said mount it on a metal table with inset legs. :laughing:
 
   / Mice and Mini Split AC units. #7  
What brand? It looks like most have a sheet metal shell.
 
   / Mice and Mini Split AC units. #8  
+1 on re-wireing it. Not complicated at all. Most MS condensers are light enough to mount on wall using shelf brackets.
 
   / Mice and Mini Split AC units. #9  
Just be sure whatever you do, you mount it where you can still get to the fins, screens, filters, etc... for servicing them. You'd be surprised how many are mounted so that you can't even remove leaves or cottonwood from the fins. I have to deal with several hundred of these units, and about 10% of them are mounted in bad locations for service.
 
   / Mice and Mini Split AC units. #10  
I have had similar issues with my pool heater and ac and thousands in damage. Poison doesn't help, moth balls help only a little. The only solution is keeping them out with a barrier. On the pool heater I used hardware cloth and sheet metal screws to cover every opening. On the AC the wiring compartment is likely the only problem spot. Plug any openings with hardware cloth or steel wool. I ended up riveting pieces of license plate to shrink the holes wires go through and then stuffing the remaining opening with steel wool. That worked for the last 2 years.

You should be able to rewire it. You may need new capacitors if they got shorted. When rewiring check all the wires for missing insulation it's pretty common to have a few bite marks away from the main damage.
 

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