[jyl]

Well, update on my minisplit install.

I installed two systems, each 18K BTU outdoor unit connected to two 9K indoor units. Took a considerable time to run the lines through closets and so on. Pressure tested with nitrogen to 200 psi, pulled 500 micron vacuum in lines, had a problem traced to a faulty 1/4” to 5/8” adapter, after I replaced that all looked good. Had HVAC service come add more R32 for the extra long lines. Tech liked my install.

One system, on south side of house, worked fine and has continued to work fine.

Other system, on north side of house, lost all its refrigerant in a few days. WTF. Got more nitrogen, pressure tested that system, found a flare connection (liquid line at outdoor unit) that was teetering on bad - actually the flare ripped off when I tried to re-torque it. Re-made the flare, this time using a FlareSeal, pressure tested to 400 psi for two days, looks good.

So now I need to vacuum out that entire system - all the refrigerant oil and humidity and so on. Disconnect the hose to nitrogen tank and a cloud of oil sprays out. Connected my $100 El-Cheapo Vevor vacuum pump and my Kinda-Cheapo Hilmor micro gauge. They both decide to fail. Replace oil in pump, clean gauge sensor with isopropyl alcohol, no help. Order a new vacuum pump, a Fieldpiece this time. Make a warranty claim with Hilmor, they say they are shipping me a new gauge, but I order a BluVac gauge anyway.

The tool budget is by now over $1,500 and I wait for the new gear to arrive. In the meantime I repeatedly pressurize each line - by now I also own a nitrogen tank and regulator - and flip open the valve core removal tool’s valve to blow out more oil.

The stuff arrives. Ooo, I feel so pro with this nice kit. I close the service valve to isolate the lines. Pressure test them and blow out oil again. Open service valves, pressurize the whole system, blow oil out again. Close service valves. Hook up vacuum pump and micron gauge to lineset A, pull out down to 350 microns, leave it overnight, next morning reads 650 microns but it’s stable there, not rising. I do the same for lineset B. Okay, I’m sort of satisfied the linesets are tight and mostly purged. Now I open all service valves, and start vacuuming down the entire system.

This takes way longer - like 45 minutes to get to 500 microns. I’ve changed the oil in the Fieldpiece once by now. I close off the VCRT and switch off the pump. I’ll see where the vacuum stabilizes, hopefully it does. Later today I’ll re-insert the valve cores and vacuum down again, planning to get to 350 ish microns, then see if overnight it holds at least 500 microns.

Assuming that works (oh please) then I’ll get my EPA 608 and buy a tank of R32 and learn how to load refrigerant back into the system. I haven’t checked how much I should need but will buy a 20 lb tank.

This is taking forever. I’m spending $ on tools. But I think my HVAC service would charge four figures to do this - they charged me $1,200 to replace capacitor and add R410 to the central AC compressor last month, and were only here for an hour. I have a few more minisplits to install in another building, and I figure I should devote some time and money to at least try to learn how to do this myself. Architect got an HVAC company estimate for those, over $40,000 - no way am I spending that, I know the equipment will cost less than $8,000.

In the meantime, the south side system has been doing a decent job of keeping the second floor bedrooms cool all by itself - set it at 70F in the two bedrooms it is installed in, and use a fan to circulate cool air to the bedrooms that the non-working north side system is not cooling.

So even though we’ve had a couple short heat waves during all of this, the minisplits have been proving their worth even with all the problems.

Meanwhile the copper lineset covers have been fabricated and are sitting under a tarp in the backyard, waiting for me to get back on the ladder. Man oh man, 16 oz copper has jumped in price - a 4’ x 10’ sheet went from $260 to $400 in the past month, so the cost of these covers was $2,300 when I had planned more like $1,600. I have 80 feet of copper covers, need to cut and miter and screw to siding, then use my nibbler to cut the excess half sheet into strips to cover the seams. Spendy but I do not want plastic lineset covers on my house.

I haven’t spent the whole month doing this - life has gotten in the way, I’ve been out of town, maybe two days devoted to minisplit install in the last 30.