Repair-It

Bought this.
https://iwae.com/shop/18k-btu-20-seer-m ... 20869.html

Actually I bought the scratch and dent. I also bought a lineset cover and condenser mounting bracket. Then I ordered a disconnect switch and whip. Last order was the 3.5" hole saw since I was told that does not come with the kit. Total spent so far around $1700. Professionally installed units start at twice this and go up from there.


Teaser.

First phase complete, mostly. The electrical. I was sort of worried about this and really it wasn't too bad. Just some tricky spots. Here's essentially what I did:

- Drilled a hole through the wood trim above my garage/basement wall and ran the wire through there to the breaker box. Did the best I could to make it neat-ish.
- Ran the wire above the garage doors, around the corner, past the chimney and to where the disconnect switch will go.
- Installed the breaker. This required me to move some breakers around because of previously moving the great room breaker (when load balancing) and there wasn't enough wire to install the new breaker under it. So I got that all taken care of but it took some effort and ended up moving the microwave, fridge and great room breakers around. I found the magic combo that let me do this while maintaining the same split phase balance in the box!

All I have to do now is when I receive the disconnect switch, figure out where it goes, drill the last hole in the sheathing and siding, mount the box, connect the whip, and wire the whip to the outside unit. Of course the outside unit is not installed so I may do that last. Considering I was going to pay an electrician for this I am glad I did it myself. A neighbor gave me like 75 ft of 12/2 so that was free. My cost for the electrical would be:

- The $70 I already spent on the disconnect switch and whip (part of the $1700 figure above)
- 20 breaker was $12.56
- Fire barrier spray foam, staples and staple gun was like $70 but I had a $25 store credit from another thing...
- I also bought 2 3/4" box grommets that I ended up not needing but will keep for future use, but they were only like $3.50

So total electrical cost to me was about $124.56 including buying the $40 Klein staple gun. No way an electrician would have done this for that.

The plans I crafted in my head for mounting the wall mount did not line up to reality when I assembled it and held it up to my house. Totally different proportions than I had envisioned.

There is an adjustable rubber bumper at the base of each upright. This is to help the base sit on an uneven (angled) surface. What I could do is place that on some pressure treated 2x4 I install at the bottom of my siding meaning the top of the foundation. This will probably help transmit fewer vibrations directly into the wood studs of my wall. That would be the middle option shown. The 4 lags for the uprights would all be in wood. The top lag for the top piece would also be in wood. The pressure treated 2x4 will need to be concrete anchored into the foundation but I would just do two.

I did have a moment of clarity with that, too. When I have my final desired location, I will simply drill holes through the siding and sheathing. Then I will go into the garage, find the holes, and add 4x4 blocking over all of them. This will give me the backing I need for wood lag bolts

Day 1.

Started by straightening some flattened fins on the outside unit. I used my fin straightening tool.

Got air handler mounted. Took a lot of exploratory drilling for studs but I found two. Secured the bracket with 3 Deckmate screws into studs. Then used two of the included screws to secure the bottom into the wall board. It won't be structural but it will at least hold the plate against the wall to add some rigidity.

For the 3.5" wall hole, I thought I had no stud. Then when I started drilling I found a horizontal stud (I guess it's not a stud). Ended up just drilling through it which took a lot of effort because I had to chisel out the 2x4 after I made some progress. The hole saw wasn't deep enough to drill through everything. This alone must have taken like 25 minutes just drilling the hole.

But we got it hung with the stuff poking through the wall.

Other progress for day 1 includes deciding on a wall mount location for the outside unit. The top piece and right piece (and bottom piece) are done. Just need to set final width and secure the left piece. For the top lag, I used a 4x4. Same for the right upper lag. The lower one actually went directly into the sill plate (drilled a pilot for all). For the bottom 2x4 I used 2 concrete anchors. Worked great.

Day 2 expectations:
- Finish mounting the left brace
- Hang outside unit on wall mount and secure
- Connect refrigerant lines
- Do electrical
- TEST IT!
- Finish job by installing the PVC line guard, spray foam in the wall cavity and just making stuff as neat as I can

kevm14 wrote: Sun Sep 05, 2021 6:48 am Day 2 expectations:
- Finish mounting the left brace
- Hang outside unit on wall mount and secure
- Connect refrigerant lines
- Do electrical
- TEST IT!
- Finish job by installing the PVC line guard, spray foam in the wall cavity and just making stuff as neat as I can

And that's what I did. Nothing really exciting so I'll just summarize each step.

- Finish mounting the left brace
This went pretty easy as I had done the right brace. Used another piece of mudflap under the lower brace lag. Not sure it's doing anything useful but I needed a shim anyway so this one is made of rubber. Bottom lag went into the sill plate similar to the right one.

- Hang outside unit on wall mount and secure
With two people this was an easy lift. Just grab from the bottom and lift up onto the mount. Then just slip in the rubber isolators under each foot one at a time, slip the bolt through and install the nut. They substituted 4 regular nuts for what was supposed to be locknuts so I decided to buy 4. The feet, in my opinion, should not be torqued very high so the rubber doesn't squish and ruin all of the vibration isolation capability. So the locking is key to prevent the hardware from vibrating loose. Bolts were M8x1.25.

- Connect refrigerant lines
A little awkward but straight forward. Before this I had to install the flange collar to cap the wall passthrough piece. I siliconed that on. Then connect each refrigerant line. Use two wrenches to keep the line from twisting. They give you a torque spec but the way the fittings are made they basically stop turning very noticeably when everything is seated. So after that just snug it and that's it. They just don't want you to stop before the O-rings are seated, and certainly when it stops, don't strip it but with two wrenches on a ladder "tight" is good enough. So now the lines are basically hanging down the side of the house, with the condensate line and the electrical line.

This was when we also had to figure out how the lines would be routed to the A/C unit. I had previously estimated that the 16 feet of line would be "perfect" which means we needed to make sure it wasn't "too short." Ended up running the lines under the unit, up and around to the line fittings on the unit. Just bend carefully by hand and this wasn't too difficult. Install and tighten just like the other end of the lines. At this point the lines cannot be reliably disconnected without risking opening the lines to atmospheric.

Then open the refrigerant valves (high and low side) one at a time with a 5mm allen wrench. Open slowly and listen for leaks. Then spray soapy water solution on all fittings and look for leaks. I didn't see any. The recourse if there were leaks is pretty dismal as these aren't flare fittings so tight is tight and that's kind of all you can do.

- Do electrical
This took a little time and two trips to Home Depot. First, locate the place you want the disconnect switch to live. With a 6 foot whip I had a constraint and the placement of the box was kind of obvious. Then I just fiddled with the box to get the fine height set where I wanted considering where the mounting bolts would go, how it would sit on the siding, and which knockouts I wanted to use for the power wire and the whip. That was also pretty obvious. Drill the hole to pass the wire through and for 12/2, a 3/8" hole was perfect. Use a cable clamp on the box, pull wire through hole and box, silicone a big ring around where the power feed goes through siding, push box onto house, and I used 3 exterior screws to securely mount it to the siding/sheathing. Then tighten the cable clamp (hope it was clocked to get to those screws). Also tighten clamp ring nut with box secured (screwdriver and hammer). Cut feed cable to length, strip, and connect the two feeds (black and white) to the disconnect switch terminals, and connect the ground to the ground block.

For the whip, I used the right angle on the box with the straight section into the A/C unit. Cut to length, strip, and connect to load side of disconnect switch terminals (think it was black and red), and connect the ground. Make sure to install the disconnect switch bar itself properly. Mine was shipped upside down which is disconnected. You can tell because the word "OFF" is right side up and "ON" is upside down. It also takes a lot of force to push the switch into the contacts so my Dad noticed this. Good thing. We would have flipped the breaker and nothing would have happened! At this point, close the disconnect switch box because it's all done.

I elected to clamp the whip to the house to make it neat. It also happens to provide two drip loops to prevent water from entering either the A/C unit or the box. Plus it uses up some of the whip and again isn't just flopping around. Looks neat even if a little...interesting looking.

Use another cable clamp for the electrical cover into the A/C unit for the wiring that goes to the inside unit. It comes with fork terminals that easily attach and they are numbered 1, 2 and 3 plus ground. Connect those. Then connect the whip and jam the stranded 10 gauge into the line 1 and line 2 terminal blocks (red and black), and also do the ground. Stranded wire is tricky but I think I made it work on the ground screw. Tighten ring nut on the whip.

Install electrical cover and tighten cable clamp for the inside unit cable.

- TEST IT!
At this point it is time to test the function of everything we did because everything after this step is sort of cosmetic (and weather sealing for the lines that come out of the house). So I flipped the breaker on and nothing bad happened. Went inside and into great room to turn unit on. But first I had to remove the shipping table and stuff. Did that, put batteries in remote, and powered on. It turned on! Set to cool and 62 degrees. Went outside, and confirmed the outside unit was humming along nicely. There are NO issues with anything. No odd rattling or buzzing. You CAN hear a humming in the garage through the wall but I really don't hear anything in the great room. So on a single floor install I would caution against using a wall mount but with a floor of separation this seems acceptable. Anyway, saw plenty of water exiting the condensate line as well so it was working great.

Then we tried heat mode and it made heat after some minutes of resetting itself to that mode. This was going great. Time to finish the install.

- Finish job by installing the PVC line guard, spray foam in the wall cavity and just making stuff as neat as I can
Started by filling the wall pass through with some 3M fire stop foam. Considering we cut through most of a fire stop horizontal stud this was actually the 100% legit code way of doing this (as opposed to the regular spray foam which is not orange). So I carefully filled up the cavity in short stages to make sure I had a handle on expansion but also filled what I wanted to fill.

Wrap the line to inside unit line connections with the included sound deadening wrap (pretty much like Dynamat) and also wrap foam insulation around those. Just make sure everything that needs to be insulated has the foam insulation properly around the lines.

Wrap the portion of line that comes from the inside unit down to where the lineset begins with the included non-adhesive vinyl wrap. This just keeps everything together I guess and makes sure the insulation stays where it needs to be over time.

Then install the bottom piece of the 90 degree cap for the pass through. I ran a little silicone on the outside cover first and used two of those same exterior screws. Then more silicone around the whole perimeter and installed the outer cap. More screws. I think I added even more silicone to the top to get it weather tight.

After this it was just a matter of installing three 4 foot sections of each of the cover pieces. First install the house side and secure. I snapped the top piece over it which is a little bit of a wrestling match since the line wasn't 100% straight and in a bundle is obviously fairly stiff. Then I realized I needed to remove this to install the next lower section. So Install the coupler piece, then the next wall side and kind of just work down the side of the house, snapping the outer cover on when possible and secure cover interfaces with the top cover of the joiner pieces.

It has 12 feet but we did not have enough refrigerant line to use all 12 feet as the line had to start making a turn before that point. So I just cut it off at the appropriate height to let the line turn 45 degrees or so, toward the A/C unit.

I found two more foam pipe insulation pieces and wrapped the exposed lines that come off the unit with them and secured using zip ties. I need to somehow cover the lineset cover as I think rain will basically just go in there and fill the lineset cover. Doesn't seem like a good idea. Or cut a small drain at the low point of the lineset...or both.

Cut the condensate hose to the proper length as this should just dump straight to the ground and not turn with the refrigerant lines. I need to secure this to the house because I don't like the 12 inches of tube just blowing around.

That's about it.

Inside there are a few control idiosyncrasies that I will point out.

First there are exactly FOUR ways to control this thing! They are:
1) Wireless remote. This is meant to hang on a wall but is also just a remote control. Right now this is really the primary interface and I have not mounted it yet.
2) Wireless smart thermostat. Haven't even put batteries in this but this is also intended to be wall mounted. You can also connect to this thermostat with your phone and control it. Not sure if I am going to use this yet.
3) Phone app direct to unit. I installed the USB smart dongle into the inside unit, connected it to my guest WiFi and can control the unit directly from the phone app.
4) There is supposed to be a way to manually control the unit with a button but it is meant as an emergency backup, would require a step ladder, and is not easy to use (it's not a real control pad, just sort of a button that you have to press in different ways to get some limited control).

So back to the #1 wireless remote. You can control the unit and it will use its own internal thermostat to sense the room temp. This has issues because the room is warmer at the installed height than where people generally are. So the set temp would need to be a few degrees higher to make the room a comfortable temp. On a hot day this phenomenon may be exaggerated. As an option, you can put the unit into "follow me" mode which uses the remote to sense the temp. This seems like what I would want, particularly where I end up hanging it on the wall. Problem is it doesn't seem to retain this setting through power cycles.

That brings me to another issue. Shockingly to me, when the unit is powered on, the inside unit fan is ALWAYS running! Even if it is not calling for heat or A/C. This annoys me greatly. It seems like a waste of electricity and also puts needless hours on the fan motor. It's kind of like an old school window A/C in this regard. The good news it the fan is very quiet especially on lower fan speeds and in the "idle" mode it uses a low fan speed. You can even set it to a super silent fan speed so at least they thought of this. They also may do this for some other reasons that I thought of. First, constant airflow makes it more accurate for the internal temp sensor to operate. I could accept this if "follow me" mode turned the fan off between cooling cycles but it doesn't. Second, since the outside unit is inverter controlled, the fan and compressor are variable speed. Rather than cycle on and off it's designed to kind of run at a capacity equivalent to your demand (which will do a great job controlling humidity also). Third, I also wonder if having the fan shut off leads to mold/mildew issues with the inside unit. So rather than shut off and have bad stuff happen, they just leave it running so if there really is no cooling for a while, stuff would dry out. This theory is backed by the fact that it has a cleaning cycle that runs the fan for some number of hours to dry everything out (before off-season or long term disuse). The fact that it has a mode for this does suggest that the stagnant water in the tray could be an issue.

The last point on the fan thing is that this is normal operation and I think the way most mini-splits work. It is what it is. It means if I really don't want the fan running, I have to manually power it off. I was hoping for more central HVAC kind of set it and forget it but I guess it has to be operated more like a window A/C. Now if I didn't care about the fan running, I COULD just set it to auto and a temp and let it do what it wants and it WOULD keep the room at that temp. I just don't see the point to running it on mild days and we are entering that period between cooling and heating season so ironically, it will be off more often than not until it gets either chilly or we get our last few hot days.

Another point on the airflow control is it has a lower louver to control vertical air direction. You can set it to swing slowly or fix it to a position (all with the remote). This is nice. It DOES have a horizontal airflow control (didn't know until I read the manual). So I could point the air toward the center of the room. However, that would be pointed to our primary seating positions for TV viewing and I think would be uncomfortable. So I will leave it pointed straight and behind seated TV watchers. It's technically the most efficient pointed straight down so swing mode could be a nice compromise to overall comfort and efficiency. I will experiment on a warm day.

Now the pics.

Unit info.

Comes with a 7 year compressor and 5 year other parts warranty, which uniquely, is held even for the DIY installation. That's why I went with Mr. Cool.

18,000 BTU is rated for 750 sq ft of room but you can adjust based on your specific requirements. My room is 24x24 but has a vaulted ceiling, 3 exterior walls AND is above the garage. And unlike conventional cycling A/C, the downside to oversizing is less with a mini-split as the outside units are typically inverter controlled, so it can vary the capacity per the demand.

The 18k BTU is 20 SEER and 10 HSPF (heating efficiency). 20 SEER is quite good and better than almost any central A/C system. You can get even higher with fancier mini-splits but I think there are diminishing returns for what you pay.

Here is a graph I made of the COP (Coefficient of Performance) vs outside temp vs inside temp, in heating mode.
I say made because they did not give me COP. I had to calculate it from the specs they gave which is a BTU of heating performance vs kW of input power. Amazingly, even at -22F with a 75F inside temp, the COP is STILL above 1. A COP of 1 is equivalent to a resistive heater. That means it is still finding heat outside. Granted the output falls to under 6k BTU and your fossil fuel heat source will VASTLY outperform this for both capability and cost but it is interesting to see nonetheless. The rating is 5F and looking at the plot it kind of makes sense as performance really is falling off by that point. The COP at which it is more cost effective to just turn up my furnace is variable according to outside temp and the price of oil (and technically electricity). I do also have a stove in the great room which I do intend to use on those cold afternoons and evenings.

Efficiency takes a dump when it gets cold for two main reasons:
1) It has to work harder to move the heat around. This is obvious.
2) More frequent and longer defrost modes.

Remember, in heat mode, it reverses the location of the evaporator and condenser. So you are "air conditioning" the outside while the condenser is inside making heat. That means moisture will freeze on the outside coils. It detects this somehow and will go into a defrost cycle. The defrost cycle is fairly simple. It reverts back to A/C mode (so the outside coil gets hot) but does NOT run the condenser fan. This maximizes the heating of the outside coil to melt the ice. I think there may also be a simple grid heater at the bottom of the unit to make sure ice doesn't form. But yeah the outside unit drips moisture like an air conditioner in heat mode. Kind of funny. In fact I am supposed to install a drain tube for that for some reason. It hits its rated 18k BTU when it is between 35 and 45F outside temp. It has more heating capacity when it's warmer than that, and less when it's colder, as you'd expect. I could graph this as well to show inflection points and stuff.

Just finished up some final tidying for my install.

- Clamped condensate line
- Added split loom to cover the exposed electrical cable for the inside unit
- Zip tied the electrical cable to the refrigerant line bundle
- Zip tied the coiled up electrical cable to the bundle
- Added plastic as a rain shield to the line bundle so rain doesn't flood the thick vinyl line bundle cover and zip tied that
- Installed the disconnect switch wiring cover (forgot, oops)
- Added the tubing to the 90 degree drain under the unit but I still don't know why this is required

Didn't know what else to do so I hung both controls. Right now the square one is controlling it which means the temp sensor is in the air handler. The remote control is just....there. it says 76 because that was the last setpoint I used with it. Kinda weird. They don't sync.

Also screenshots from the app.
The mini-stat connection is via Bluetooth. The upper thing is direct to the wifi dongle in the air handler. They give you many ways to control it but none that I really want. I want a wall mount thermostat that doesn't require IR and line of sight to work. I may try to rig up a mirror on the wall so the IR signal gets to the unit and back. Not sure if it will work. For now, using the square unit as it is easy to see stuff and looks more like a normal thermostat.

I haven't really had a chance to run this on a hot day (hottest so far was about 80). But it seems like it doesn't dehumidify as well as I expected? I dunno, it doesn't drop the humidity level very much when it runs. Is that because 18k is oversized for my room, especially on mild days, even considering that it will throttle itself down? It seems to drop the temp pretty quickly. In a normal system you'd say this was oversized but it's not like it shuts off and stops removing humidity. It just throttles down. In fact throttled down I guess I'd expect even better humidity removal.

Time will tell. It may be that with a little more heat load it will control the humidity just fine. It certainly makes water from the condensate line so it's removing plenty. I guess I expected more of a drop on my hygrometer while it runs. I feel like my window units (well, my two newer GE ones) do a better job dropping the humidity, especially with their fans on lower speeds. I may have to wait until next summer to test on a hot/humid day. Again, it probably does fine. I just expected more humidity control in more mild conditions.

It's also fair to point out that I may have a measurement issue causing this perception. My main downstairs hygrometer seems to be reading low making me think the great room unit is under performing. But maybe it's not.

Tried heat mode on some of these cooler mornings lately. I am happy to report that it seems like it works even better in heat mode. I set it to 68 and it keeps the room exactly at that temp. I also noticed that it cycles the outside compressor. When it does this, it moves the vent louver to the straight out position and the air gets room temp (obviously). Then when it needs to turn the compressor back on, it directs the air to the floor and it's warm. But yeah it keeps the temp right at the set point which is pretty awesome. Expectedly, the heat doesn't go too far out of the great room. When I run the wood stove, the room tends to be in the mid 70s and I use a box fan to direct hot air out of the room (actually cool air into the room which pushes warm air out of the room). But I don't want to run the mini-split at 75 just to try to warm the house. That's really not the purpose. So for its intended function it seems to work exactly as it should.

What I don't know is how it will react when I run the furnace. I guess it will just run even less. But that's why I want to close the duct dampers down. Maybe I don't want to close them all the way. I will experiment. The furnace is not online yet so it will be a week or two yet.