Works by Coomer

House Has Heat Again!

Dec 28, 2021

House Has Heat Again! lmage

After almost three years surviving on space heaters and debating what to do heat-wise, heat is installed. We got a Pioneer 24,000 BTU ductless mini split unit and installed it ourselves, which was painful at times and took a while, but now it's working and we have good heat (and A/C) in the house.

Only a small 3" hole must be drilled through the wall to install the interior unit. Two refrigerant lines, a condensation drainage hose, and the electrical cables pass through here.

We elected to pour a concrete pad for the outside unit to sit on and bolt to, and it works well after a second application of concrete because the first wasn't level. We left the 2x4 frame in place around it, as it'll get covered up by a shed soon anyway.

Our unit runs on 240v electrical, and I wired it up using an existing un-used 110v 12/2 cable run that ran into the extension of the house in the crawlspace. We don't need 110v power on this circuit so 12/2 (3 wires) does the trick just fine. That circuit is now connected to a 30a dual breaker at the panel and routed to the junction box on the south crawlspace side where it exits to the exterior disconnect switch above the mini split outdoor unit.

It was the right choice, for many reasons:

1. Furnace was about 18-20 years old and failed due to a bad circuit board.

2. Ductwork in the house was mostly damaged flexible ducting that was filled with garbage, and it all needed replacing. When the furnace worked, the whole house smelled dusty, partly due to the garbage and dirt inside the ductwork and partly due to one end of the ducting ending in a pile of loose dirt underneath the kitchen, not at a register. This section of the house cannot be accessed safely currently.

3. The heat pump, variable speed compressor, and various other features make the mini split very efficient, on par or better than natural gas in many places. Our gas is pretty cheap so it's probably still a bit more expensive, but we plan on getting solar with a battery bank at some point so going all electric in our house makes sense.

4. Price was not bad. All in, including various tools I bought for the job (and can use if I install a second mini split in the garage), our costs were around $1600. $1400 or so for the unit and $200 in electrical supplies, concrete, vacuum pump, flare nut crow foot wrenches, etc. Manifold gauges and hoses were borrowed, and would've tacked on an extra $150 if we had to buy them ourselves.

5. Doing it ourselves means we know how it's done and how it can fail and how we can fix it. With contractors, you never know what you're gonna get - case in point - my fix-and-flipped house. And there are many cases online of contractors and professionals kinking lines, etc. It took a long time, but we took the time to do it properly and I think the whole install is going to last.

Technical Install notes:

0. Our 16ft line-set came with flare nuts and flares already done at both ends, so I didn't have to do that step. Super nice. Speaking of super nice, it also comes pre-charged with the R410a refrigerant, and the only way to legally buy R410a in Colorado is to buy a mini split or other unit with the refrigerant already inside. The pink bottle of R410a refrigerant by itself (used to service various HVAC equipment) can only be purchased by a licensed tech, as it's a dangerous greenhouse gas if used improperly. As long as you can follow the procedures properly, no HVAC tech is necessary to install this thing.

0a. Don't be an idiot like me and kink the tubing. Be very very careful, always keeping the bend point moving slightly, and don't try to use a bucket as a bending tool. When you do cause a big kink, a crescent wrench slowly rotated around the kink point and slowly tightened over several rotations can round it back out somewhat.

1. 1/4" line flare nuts don't use a SAE or metric sized wrench. It's between 5/8" & 11/16" and 16mm & 17mm, probably some specialized weird size that HVAC techs know. I couldn't find any crow foot wrench that would work so just estimated torque with a 10" Crescent wrench. The 1/2" line flare nut uses a 15/16" flare nut crow foot wrench, and that one could be torqued properly using a torque wrench. All fittings were checked for leaks with soap and water while under pressure and no leaks were found.

2. Gas-release valves use a 5mm hex key/allen wrench. The one from the large gray Buffalo set worked well. The one from the made-in-China T-handle set was too small.

3. A 5/16" female to 1/4" male adapter is required to hook the manifold gauges up to the service port on the mini split. It must have the inner pins to engage the shrader-style valve. Grainger had this in stock for $7.50.

4. The Stark 1/4hp 3cfm vacuum pump I bought has holes in the area where you can see the oil level, and these look like holes in a pulley and like it should spin. It does not, and that is normal for vacuum pump operation.

5. Always double-check instructions and CLOSE LOW SIDE VALVE ON MANIFOLD once vacuum is pulled in lines and the next step is to wait to ensure they hold pressure. Don't be an idiot like me and miss this step and release some pressurized refrigerant during the 5-second gas-valve opening test phase.

6. Wait a few minutes in each of the HEAT and COOL test modes, as on first start it can be slow to get A/C and (especially for us, took a few mins) heat working.

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