Mini Splits refrigerant line insulation help.

JackW

I have a four-unit Mitsubishi Mini Split cooling/heating system. All the lines run outside the house because we are on a slab. As you can see in the pictures, the lines are covered by formed aluminum sheeting. Since it wasn't sealed very well, mice and chipmunks have had a field day inside the sheeting, using the insulation for their homemaking. I'm in the process of taking all the covers off and repairing the exposed copper pipes. Most of it has been small areas that I have wrapped double-backed aluminum foil insulation around, then sealing it with PVC and aluminum tape. As you can see, they wreaked havoc with the up lines out of the condenser unit. Given the amount I have to replace, is the aluminum foil insulation ok to use, or is there a better alternative? The lines are 1/4" and 3/8," I can't find any type of foam insulation that small of a diameter. Any suggestions will be greatly appreciated.

Jack

mattmia2

Foam insulation is available that small but it isn't usually pre-slited with an adhesive closure. You will have to slit it and zip tie or tape it together. Aluminum up against the copper isn't a great idea, the dissimilar metals can cause corrosion and potentially pinholes in the copper.

JackW

@mattmia2 I never thought about the dissimilar metal effect. Unfortunately, I haven't been able to find anything in those small diameters. Maybe there is some other foam product out there that I could use. I'll have to do some more looking. Thanks for the advice.

JackW

@mattmia2 Let me ask you this. How tight does the foam insulation wrap need to be around the copper pipe?

pecmsg

Refrigeration supply houses have 1/4, 3/8 and 1/2” split armorflex 

mattmia2

I'm pretty sure this is the size for 3/8" tube. You might need to find someplace that specializes in refrigeration or insulation to find it for 1/4" tube size.
https://www.supplyhouse.com/K-Flex-6RX068038-3-8-Pipe-O-D-x-3-4-Wall-Insul-Tube-Pipe-Insulation-6

GGross

We started selling only linesets with that tough outer layer for this reason. I think these ones below may work for you, thats a good brand anyway if you click the brand name on the website it will show you some other options as well

https://www.supplyhouse.com/K-Flex-6RX068028-1-4-Pipe-O-D-x-3-4-Wall-Insul-Tube-Pipe-Insulation-6

https://www.supplyhouse.com/K-Flex-6RX068038-3-8-Pipe-O-D-x-3-4-Wall-Insul-Tube-Pipe-Insulation-6

EBEBRATT-Ed

I would also put the sheet metal chase back on when you are done and seal the ends somehow

JackW

@EBEBRATT-Ed. That's what I'm going to do. The biggest challenge will be where the lines leave the condenser unit and start up the sheet metal covers. Not sure how I'm going to seal that off with all the insulation and wiring. Thanks.

JackW

Thanks for all the suggestions on where to buy the insulation. I just ordered several 1/4" and 3/8" sticks.

JUGHNE

I have used PVC line set covers and stuffed any obvious openings with steel wool.
It may keep the little critters out.

EBEBRATT-Ed

@JackW

maybe you can find some plastic mesh to shove in there and then spray foam the end and cover it with and end cap as best you can. nothing is 100% but you can slow them down

mattmia2

Bronze wool might be a better idea than steel. Probably want it to still drain.

pecmsg

mattmia2 said:

Bronze wool might be a better idea than steel. Probably want it to still drain.

Or stainless Steel scrubbers. 

JackW

@EBEBRATT-Ed, I've thought about using foam, but I'm not very good at applying it, plus it would make taking it apart a pain in the butt. Thanks for your help.

JackW

@JUGHNE, there are so many lines going in that by the time I cut openings for all the copper and electrical lines, I would have much left. Bronze wool was mentioned; I might take a look at that. Thanks for your help.

JackW

@mattmia2, so far, I think that is my best option. I could stuff a bunch of it up inside the cover from the bottom. Of course, I would have to check on it frequently, but taking the covers off is not a big deal. Thanks for your help.