Mini split installation for a house

[Jim Becker]

The thing is, a "yuge" percentage of the outdoor HVAC units, traditional or mini splits are not covered over, in my observation. I truly wonder if it's really an issue. My overhang on the shop is 12" and the unit, mounted on the ground, must be 12" from the wall. I'm honestly not worried about it.

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[Ken Fitzgerald]

The thing is, a "yuge" percentage of the outdoor HVAC units, traditional or mini splits are not covered over, in my observation. I truly wonder if it's really an issue. My overhang on the shop is 12" and the unit, mounted on the ground, must be 12" from the wall. I'm honestly not worried about it.

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My AC condenser isn't covered. I do put a cover on it in the late fall as my neighbor's large maple massively overhangs my house and shop. I don't want to have to clean the leaves out of the condenser. With a high efficiency furnace, the condenser isn't used in the winter. It would be interesting to know which direction the fan circulates the air. If the air is coming up through the condenser, I'd be less worried about it.

[Jim Becker]

My AC condenser isn't covered. I do put a cover on it in the late fall as my neighbor's large maple massively overhangs my house and shop. I don't want to have to clean the leaves out of the condenser. With a high efficiency furnace, the condenser isn't used in the winter. It would be interesting to know which direction the fan circulates the air. If the air is coming up through the condenser, I'd be less worried about it.

With a heat pump, the condenser/compressor is used year-round. The fan blows out away from the wall on these mini-split units, while the fan on the heat pump on our house blows up or down...I never checked. So the fan direction isn't a factor with the mini split and weather. I somehow think that the weather guidance is more about optimizing things since it's generally impractical to have something like a roof over these things and most of them don't. Just take a look at any multi-family apartment tower around the world. The units hang out on the outside of the building and are essentially unprotected from weather, sun, etc.

[Kris Cook]

Here is my install. Bought wall-mount brackets and bolted the unit to the brackets through rubber pads.

12-2 romex to the box on wall (internal wired during construction). Stranded inside sealtight conduit from box to unit. Also put the control wires inside sealtight to inside of the lineset cover.

-0.3 degrees here this morning in Montana. T-stat in shop set at 60 degrees overnight. 60 degrees in the shop this morning. 70 degrees now with the wood stove taking over duties.

[Zachary Hoyt]

Thank you all, that's very helpful. I won't worry anymore about the rain getting on it. The pullout box arrived at the post office today, so now I just have to wait for the other 4 packages to be delivered and the weather to warm up a bit. It's going to be up to 40 next week, if the shadows of these things remain unaltered by the future.

[Zachary Hoyt]

The forecast today was for low-mid 30s and cloudy but no rain, so I went ahead and put in the mini-split. I started about 8:15 to make the brackets, and didn't get them welded up till about 9:30, as I had to get the old stick welder out of the shed and over to the workshop. Most things went pretty smoothly, but a few were odd. For instance the mounting screws for the indoor unit were supposed to be screwed into studs, but they were only 1" long. Luckily I was screwing them into plywood anyway. I had just barely enough length on the lines, and a few more inches would have been nice.

I tested it and it does work, both on hot and cold, and showed no leaks when I checked with soapy water both before and after the test run. I have not wrapped the lines because I am a bit confused by what the manual says. There are two of those sticky pad things, and I am not clear if one gets wrapped around each line at the air handler connections, or if one gets wrapped around both of them and the other one around the other two connections by the compressor. I am also not clear how long the drain hose should be. I guessed it should come down to the corner where the lines go horizontal, but maybe it should end higher up. I also don't know if I need to wrap the lines under the addition, or if they can just hang from the bottom of the joists as they are. I'll need to order a line cover kit for the part on the outside of the house, I imagine.

The indoor unit is very quiet and the outdoor one is pretty quiet on the outside of the house, but when I was running the unit at max heating for 5 minutes during the test run it made the wall vibrate, so from inside it sounded like there was a diesel engine idling on the side of the road out there. I don't know if it would be so loud under normal conditions. I'm very thankful for all the help with this project from kind folks here.

[Maurice Mcmurry]

Mr. Cool and Pioneer appear to be identical. Good Job Well done. I will zoom in on your insulation questions.

[Bill George]

Your allowed to run Romex exposed and unprotected from the main box to your disconnect? Instead of bolting to the house where vibration can and will be transmitted to, I would have set on concrete blocks. Good job with no leaks!!

[Zachary Hoyt]

Thank you both. I was lucky to get it hooked up with no leaks. The electrical inspector said I could use conduit or UF cable, which is what that is.

[Jim Becker]

The two sticky pads are for the individual connections where the line set attaches to the tails from the interior unit. They are to keep things quiet so the connections don't vibrate together. Once you have each of those those wrapped, you do the remaining wrapping to finish up and make things neat. Electrical tape is your friend for keeping the non-adhesive wrap tape clean and neat; you can buy white if you're anal like me. I'm surprised that the inspector is fine with that UF "uncontained" the way it is for the connection to the breaker from the disconnect. But all decisions are local...

[Zachary Hoyt]

Thanks, that's very helpful. I've got a roll of white electrical tape already since I had to use a little to mark the ends of the neutral on the service installation where all three wires were black. I'll plan on wrapping all the exposed (outside the building) lines if I have enough of the non-adhesive tape to do it. About the wire, that's what he told me on the phone, but maybe he'll feel differently once he sees it.

[Dwayne Watt]

Did you install isolator pads between the wall bracket and outdoor unit? Effectively, you need isolation on both sides of either the mounting bracket or the outdoor unit housing to dampen any vibration coming from the outdoor unit (little or no metal to metal contact). Described differently, either the wall bracket or the housing foot need to be sandwiched between isolator material at the bolted connection between the two, not on the wall itself.
Also, your brackets look pretty solid (stiff). That's not helping your vibration/noise transmission conditions. Probably too late for this winter, but a ground mount would effectively eliminate all equipment related indoor noise.

[Zachary Hoyt]

Thanks, that makes sense. I did put the provided rubber pads under each foot, on top of the bracket, but the bolts of course go right through both pieces and probably carry the vibrations. Pouring a pad under it is probably indeed the best bet once it warms up in the spring.

[Bill George]

I used white duct tape, both lines are insulated and I bundled both together so it looks nice.

UF is for underground and its the same as Romex when it comes to protection, never can be exposed like you have it without protection. I am thinking your Inspector thought it was going to be buried! Re-reading your post it appears the Inspector has not seen it yet.

You can place the rubber cookies under the unit and place on concrete blocks. Your not going to like it when that angle starts rusting. Good job getting it in with no leaks and working right off.

BTW here in Iowa today it was in the 50s and will remain the 40-50 degree range all week. I don't know where your at but last week here it was darn cold. Just saying with the Quicksetting Ready Mix you can pour concrete. Leave the angle in place until the concrete pad is cured and then lower down on treated 2x4 or other if needed, and the pads.

[Dwayne Watt]

I was intrigued by the UF cable question. A quick internet search indicated that UF can be exposed per the NEC as long as it is not located such that it can be damaged. The example that was shown was UF cable stapled to wall siding under an eave to provide power to an outdoor light. The example for this mini-split installation may or may not meet that expectation for damage protection.