Mice and Mini Split AC units.

[GLyford]

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?

 

[jhasafety1]

What brand is your mini split?

 

[tallyho8]

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.

 

[tallyho8]

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.

 

[MossRoad]

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.

 

[MossRoad]

That was kinda wordy.....

guess I just could have said mount it on a metal table with inset legs. :laughing:

 

[Kyle_in_Tex]

What brand? It looks like most have a sheet metal shell.

 

[jaxs]

+1 on re-wireing it. Not complicated at all. Most MS condensers are light enough to mount on wall using shelf brackets.

 

[MossRoad]

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.

 

[tractchores]

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.

 

[kenmac]

easy fix...... Buy a couple of cats

 

[GLyford]

Unit is a mitsubishi, looks like this:



It is on wall brackets, 3 ft from the ground. I suspect the big problem is the oval slots on the end and back. They are seriously big, like jam three fingers in.

I picked up 1/4" hardware cloth last night, so will use that. I was wondering if bug screen would clog and be more of an issue, thank you for your feedback on that. I had a friend who had a window AC fan blocked by a yellow jacket's nest but at least that was an easy fix...he found it after the nest was dead and once removed, his unit still worked.

Part of the issue with repairs is what I have time for and what my repair guy is willing to do. This unit is computer controlled, has a VFD for the fan, etc. Pretty sure the main board has been fried. Not sure on the actual compressor motor but there are enough parts in there that are messed up that my guy can't get parts for, he's looked. And have I mentioned that the whole thing stinks like crazy?

Going to get hot again this week, it will be good to have it done, we are scheduled for tomorrow.

Next thing is to see if I can put screws in it to mount the hardware cloth or if I will have to come up with some way to surface mount it.

 

[GLyford]

easy fix...... Buy a couple of cats

To keep the mice away, I'd have to pretty much leash the cats to the unit. There are hawks, fox, and coyote in the area...and my Aussie has a high prey drive. I do not see this ending well. Oh, and the wife and I are allergic.

 

[tractchores]

I've got cats and it doesn't help. For your repair if you can get the board the rest of it is probably fixable with standard parts. Unfortunately the boards can be super expensive. Some online sites sell armor to protect against pack rats in the southwest, if you search online you might get lucky. The kits are just screws and 1/4" hardware cloth cut to the right sizes and a diagram showing where to attach it.

 

[GLyford]

Thank you. Sounds like I am mostly on the right track.

 

[GLyford]

Unit was replaced this AM and is working.

After the guy left, I took the covers back off and looked around. There is a bulkhead between the condenser and the compressor compartments. From the trail of mouse poop, the guess is that they were getting in by running up the electric meter, and across a horizontal line cover to where the lines and wiring enter the back of the compressor compartment, and weren't any signs they had gotten in the condenser side.

When the old unit was removed there were still 4 live mice in it.

The first thing I noticed is that there was an unused open wire knockout where the lines come in. I had some plugs, so slapped one in. If I had to guess, there is a 90% chance that alone would fix all the issues.

I also wedged a sticky trap in the bottom of both compartments. My wife had some mouse baits on hand, so I put a couple in the compressor side just in case.

 

[GLyford]

Unit was replaced this AM and is working.

After the guy left, I took the covers back off and looked around. There is a bulkhead between the condenser and the compressor compartments. From the trail of mouse poop, the guess is that they were getting in by running up the electric meter, and across a horizontal line cover to where the lines and wiring enter the back of the compressor compartment, and weren't any signs they had gotten in the condenser side.

When the old unit was removed there were still 4 live mice in it.

The first thing I noticed is that there was an unused open wire knockout where the lines come in. I had some plugs, so slapped one in. If I had to guess, there is a 90% chance that alone would fix all the issues.

I also wedged a sticky trap in the bottom of both compartments. My wife had some mouse baits on hand, so I put a couple in the compressor side just in case.

 

[AWSubie]

"Just One Bite" Rat poison is the best I've ever come across. Before using it I used "environmentally" safe deterrents and last winter rats and mice destroyed the 12v DC and 115 AC wiring in my RV. Very costly and time consuming to repair. I feel your pain.

 

[tractchores]

Just be careful with the bait as it attracts them. Sounds like the problem should be solved!