The Mini-Split

The Saga

three picks, two funerals

Three picks, two funerals. The first was the Mitsubishi MSZ-FS09NA — hyper-heat, CN105-moddable, and anchored to a $775 clearance condenser that turned out to be too good to be true: the matching indoor head was discontinued everywhere, the cheap condenser an orphan. Lesson banked — stock-check clearance before it becomes the plan. The pivot was the FX09, and the FX09 survived its stock check and died at the checkout: $2,652 is flagship money for a 169-sqft office with a working gas furnace already standing behind it. That's when the search stopped chasing a badge and started chasing the field — a July 18 sweep of Mr Cool, TOSOT, Senville, Pioneer, Della, Klimaire, and Fujitsu — and found something better than a consolation prize.

The Pick

the office · 120V · decided, third time honest

A unit at a fifth of the FX09's price with a cleaner local-control story than the CN105 solder mod: built-in WiFi that Home Assistant's native Gree integration drives over local UDP, documented in TOSOT's own Home Assistant guide. One cloud touch to bind WiFi at setup, then LAN-only forever. No dongle, no soldering, no Kumo.

Why 9k, not 6 or 12: the room math hasn't moved — 169 sqft with spillover duty, 6k leaves no margin, 12k short-cycles, a modulating 9k covers both the leaky era and the post-insulation one.

Why 120V

voltage ≠ efficiency

The voltage rationale has moved: 240V was only ever where Mitsubishi's hyper-heat catalog lived. Nothing about 120V costs this unit efficiency or capacity — SEER2/HSPF2 numbers above are for the 120V model as sold.

At 120V this unit wants a dedicated 20A circuit on 12 AWG (MCA 19A, MOP 20A; power lands at the condenser, the head feeds off the interconnect) — and in an outage it runs from any portable inverter generator's household outlet, no 240V inlet required (see Resilience).

The Install Runbook

flare-and-vacuum, not quick-connect — the honest shape

Standard flare-and-vacuum, not quick-connect — and that's fine. The lineset ships pre-flared with the charge waiting in the condenser, so the stock install is a short, ordered list, not a mystery:

1. Lineset ships pre-flared, charge already waiting in the condenser — no brazing.
2. Mount the plate into studs; drill the wall hole 2.2–2.8", sloped slightly downward so condensate runs outside, not into the stud bay.
3. Hang the head, connect the pre-flared lineset — torque the flare nuts to the manual's table: 12–14 ft-lb on the ¼" liquid line, 23–29 ft-lb on the ⅜" gas line.
4. Pull vacuum at the gas-valve service port — 5/16" SAE, so the ¼" hose needs an adapter. The manual's own bar is loose (−0.1 MPa for 10–15 min); do it right anyway: micron gauge at the system end, down to 500 microns or below.
5. Valve the pump off and hold 30 minutes, not the manual's 10–15. Stays under 500 = good. Creeps to 1,000–2,000 and stalls = moisture. Climbs without stalling = leak.
6. Crack both valve cores open only slightly with the hex key — don't open them fully yet.
7. Bubble-test all four joints. A weeping flare gets caught with the valve barely open and almost no charge lost — this is the substitute for the nitrogen pressure test (why nitrogen is skipped). Only open fully once every joint is clean.
8. Drain the pump, wrap the lineset, commission the system.

Flaring only enters the job if a run gets shortened or a flare gets damaged. Max lineset run is 65 ft; there's no published charge-per-foot table, so the honest answer is stay near the 16 ft that ships in the box.

The Shopping List

what the box doesn't hold — Amazon layer landed, the orange-store run is still ahead

○ open To buy: the condenser landed Jul 23 — freight box dinged, unit fine — and the head unit followed Jul 24. Everything below is the not-in-box layer for the west-wall run: panel exit and exterior conduit down to the condenser's wall bracket, the breaker and disconnect, the mount, the hole through the brick, and the fine stuff a flare-and-vacuum job needs to finish right.

stock checked jul 24 2026 · home depot independence #3006 · 4210 s lees summit rd · counts are stale — the trip never happened; re-check the whip especially, it was down to 3

Clocks, as of Aug 5: the freight-claim window (5 days from the Jul 23 delivery) has closed — no photos were taken, but the unit shows no damage, so it's a non-event. Registration is still open: 30 days from delivery lands around Aug 22–23 for the +6 months of warranty. That's the only clock still running.

The Run — panel exit + ~20 ft exterior conduit (≈$110)

The Power — breaker, disconnect, whip (≈$45; +$37 GFCI ordered, +$65 combo today)

The Mount — condenser on the wall (≈$65–105, bracket lane dependent)

ALT: Diversitech EL1838-3 ground pad $35 + risers ~$20 if bracket-height brick is ever questionable.

The Hole & Seal (≈$24 left — core kit, sleeve, and cover already landed)

The Fine Stuff (≈$22 left — Nylog and cork tape already landed)

What's left on this list: Run ~$110 + Power ~$50–108 (breaker, disconnect, whip, GFCI call) + Mount ~$62–102 (bracket call) + Hole & Seal ~$24 + Fine stuff ~$22 ≈ $270–365, down from the original $385–505 because the Amazon layer (~$148 of core kit, sleeve, cover, Nylog, cork tape) is already paid and sitting at the house.
Total still to spend: that plus the refrigeration tools (~$210–235) = $480–600. With the unit ($595) and the materials already bought, the project lands ≈$1.3–1.4k all-in — nitrogen skipped, which keeps $150–250 out of it.

The lanes, revised for the slip: losing the deadline reopened the ship-to-store lane, and that's worth real money.
ORDER NOW — DuctlessAire BPC-3LP bracket $35 instead of the Everbilt at $74.98. The Everbilt was only ever the pick because it was in stock that day; nothing is urgent now, so take the $40 back. Same logic on the GFCI if it's wanted: $45 online beats $73.48 in-store, and NEC 210.8(F) Exception 2 runs through Sep 1 2026, so an August install is still inside the exemption either way.
IN STORE — everything in the run/power tables, plus anchors, caulk, pads, Wagos.
AMAZON, delivered and inventoried Aug 5 — BEWAVE lineset cover, TAUROX sleeve, Pangda cork tape, Nylog Blue, Luney core kit, Mastercool torque kit. Complete; nothing outstanding on this lane. The Gardner Bender duct seal is a Home Depot line, not an Amazon one — it's in the run table above.

• Register the unit before ~Aug 22–23 for the +6 months of warranty.
• Leave a service loop of lineset and interconnect at the head — brick and frame move.
• Re-torque the flares after the vacuum hold test, not just once.

Tools & Materials

~$210–235 still to buy — the refrigeration end was never ordered

○ open The Jul 25 Amazon order covered the materials layer and the torque wrench. It did not cover the refrigeration tools. Without a pump you can hang the head, run the conduit, and land the power — and then stop cold, because you cannot open those valve cores. This is the long pole now, not the Home Depot trip.

Already here

Still to buy — the refrigeration end

Still to buy ≈ $210–235 (pump, gauge, adapter) before the optional lane. Prices verified Aug 5 2026 except the VG-760, which Amazon wouldn't serve — check it before clicking.

Nitrogen: skipped, on purpose

◆ decided No nitrogen pressure test. That's a call, not a corner-cut, and the reasoning is specific to this install:

• The lineset ships pre-flared from the factory — no flares are being cut, and bad flares are where flare leaks come from.
• Four joints total, two at the head and two at the condenser.
• The torque wrench and the Nylog are on hand — the two things that actually prevent flare leaks.
• TOSOT's manual doesn't ask for it. It specifies a vacuum and no nitrogen step. Midea and others are the same; Carrier wants a 600 psi test, but Carrier isn't who sold this.

The honest limitation: vacuum decay is a weaker leak test than pressure. Vacuum pulls joints tighter, so a marginal flare can seal under vacuum and weep at operating pressure. Severe leaks show in a decay test; small ones often don't. The risk that actually bites: find the leak after releasing the charge and recovery needs a machine, a scale, and an EPA 608 card to buy R32 — that's where the project stops.

The $0 mitigation is already in the runbook: crack the service valves open only slightly, bubble-test all four joints, and open fully once they're clean. A weeping joint gets caught with the valve barely open and almost nothing is lost. This is what DIY installs actually do in place of the pressure test.

If it's ever wanted anyway: Airgas, 1845 Foxridge Dr, Kansas City KS (866-935-3370) — a 20 cu ft nitrogen exchange runs about $34; Feldmans Farm & Home also exchanges welding tanks under 45". But the gas is the cheap part: add the cylinder itself (buy or lease, plus deposit) and a CGA-580 0–600 PSI regulator at $60–90. First-time all-in $150–250 — a third of what the unit cost, for one test on four factory flares. That math is most of the decision.
Hard no: never substitute shop-compressed air. It carries moisture into the system the evacuation exists to dry out.

Disconnect, whip, cover, and the rest of the materials layer moved to The Shopping List above.

Fine Print

the parts that aren't the pick, but matter

• R32, mildly flammable (A2L): no open flame near the work; the 9k unit's factory charge sits under every room-size threshold that would otherwise trigger extra ventilation rules.
• Freight, not the unit: the known weak spot is the pallet, not the hardware — photograph it on arrival and report any damage within 5 days.
• Register within 30 days for the extra 6 months of warranty coverage — a form, not a phone call.
• TOSOT Direct, the retailer: reviews of the storefront itself are mixed; the hardware underneath is Gree's, and that's fine. Judge the machine on its own.