Mini-Split Annual Service

Purpose

Define the annual service protocol for residential ductless mini-split systems (single-zone or multi-zone). Mini-splits aren't "ductless = maintenance-free" - the indoor head's blower wheel and drain accumulate dirt faster than a ducted system because there's no return-filter trap upstream. A neglected mini-split smells musty within 2 - 3 years.

Scope

Applies to:

• Single-zone residential ductless mini-splits (1.5 - 3 ton)
• Multi-zone residential systems (up to 5 indoor heads)
• Cassette and wall-mount indoor units (limited inspection on ceiling cassettes - see warning)

Excludes commercial VRF/VRV systems (separate scope), and any unit with visible refrigerant leak symptoms (that's a service call, not maintenance).

Responsibilities

• Dispatcher confirms outdoor unit access + number of indoor heads at booking
• Lead technician runs the protocol on every head + the outdoor unit
• Customer is briefed on indoor-head cleaning + drain-pan inspection findings

Procedure

Indoor head (target: 30 min per head)

1. Customer briefing on which heads will be serviced.
2. Remove the front filter screen. Hose off and air-dry while continuing.
3. Vacuum the indoor coil with a soft-brush attachment. Don't bend the fins.
4. Inspect the blower wheel for biological buildup. Most mini-splits 2+ years old have visible growth. If heavy → quote a deep-clean (blower wheel pull + bib-system wash on the coil).
5. Verify drain operation. Pour 8 oz of water into the drain pan via the front; watch for clean drainage from the outdoor termination. Blocked drain = blower-wheel water dripping inside the customer's wall.
6. Wipe the indoor cabinet exterior with a damp cloth.
7. Replace front filter.
8. Cycle the system on cool + heat to verify both modes operate cleanly.

Outdoor unit (target: 25 min)

1. Cut power at the disconnect.
2. Visual inspection - cabinet, refrigerant lines, electrical conduit.
3. Vacuum + brush the outdoor coil. Comb any bent fins.
4. Inspect the line set insulation. UV-damaged insulation is replaced as a follow-on quote.
5. Check torque on flare connections (NO disassembly - just torque verification with a torque wrench at the rated value).
6. Verify the line-set drain (heat-pump units) operates.
7. Restore power. Watch the system through one cool + one heat cycle.
8. Measure operating pressures + superheat / subcool on the line-set ports.

Acceptance Criteria

• Every indoor head's filter cleaned, coil vacuumed, drain verified
• No visible biological growth on blower wheels (or deep-clean quote presented)
• Outdoor coil clean, fins straight
• System runs cleanly in both cool and heat modes
• Operating pressures within manufacturer spec
• Field report documents inspection findings + any deep-clean upsell

References

• Manufacturer service literature (DAIKIN, Mitsubishi, LG, Fujitsu, Carrier)
• ACCA Standard 4 (Maintenance of Residential HVAC Systems)
• Manuall internal: Heat Pump Refrigerant Charge Reference