Daikin mini-split error H6: position sensor abnormality (compressor start-up failure)

By Jason Dearmin · Last reviewed November 14, 2026 · How we check facts

What H6 means

Daikin service manual DAMA-SM-23-020 (FTXC series) describes H6 as a position sensor abnormality. The unit detects it by checking the compressor running condition through the position detection circuit. The decision condition is that the compressor fails to start in about 15 seconds after the run command is sent; if the error repeats, the system is shut down.

Reset condition

The manual lists the reset condition as continuous running for about 11 minutes without any other error. So a unit that recovers, runs, and then shows H6 again later is still reporting a start-up problem.

Daikin's list of supposed causes

• Power supply voltage out of specification
• Disconnected compressor harness
• Defective compressor
• Defective outdoor unit PCB
• Start-up failure caused by a closed stop valve
• Input voltage out of the specified range

The troubleshooting flow chart starts with turning off the power and checking that the supply voltage is as rated, then checks the discharge pressure (replace the stop valve if not OK) and the diode bridge. These steps need meters and refrigerant-side knowledge, so they belong to a technician.

What a homeowner can do

• Check that the breaker for the outdoor unit has not tripped and has stayed on.
• Look at the outdoor unit and clear snow or ice from around it without touching moving or electrical parts.
• Turn the system off at the remote, wait a few minutes, and restart once.
• If H6 returns, record the model number and call a licensed HVAC technician.

Safe homeowner checks for Daikin H6

1. Check the breakerConfirm the outdoor unit breaker is on and has not tripped.
2. Clear snow and ice around the outdoor unitGently remove snow or ice from the sides and top without touching internal parts.
3. Restart onceTurn the system off at the remote, wait several minutes and restart once.
4. Call for serviceIf H6 returns, record the model number and call a licensed technician.

Frequently asked questions

Does H6 mean the compressor is dead?

Not necessarily. The compressor is one of six causes in Daikin's list. Voltage problems, a loose harness, a closed stop valve or the outdoor PCB can also produce the same code.

Is H6 a Mitsubishi code?

Mitsubishi Electric's MSZ-GX manual error table does not list H6. The H6 definition on this page comes from Daikin service manuals. Other Mitsubishi models can use different code sets, so check your own manual.

Sources

• Service Manual DAMA-SM-23-020: Inverter Split Wall Mounted Heat Pump, FTXC Series (section 4.1 and 4.20) (Daikin) Covers: Daikin FTXC-series inverter wall-mounted heat pumps (60 Hz).
• Daikin RXS18LVJU service manual SiUS091133, 4.20 Position Sensor Abnormality (Daikin (via easymanua.ls)) Covers: Daikin RXS-series outdoor units.
• MSZ-GX Operation Manual, "Error Code Display Mode" (A2L series, 2024) (Mitsubishi Electric) Covers: Mitsubishi Electric MSZ-GX / MUZ-GX A2L-series wall-mounted units. Other Mitsubishi lines (for example FH, GL, GE) can use different code sets and LED blink patterns; use the manual for your exact model.

Safety note: this page is general information drawn from the sources above. Gas, combustion and line-voltage repairs belong to a licensed professional. Your own equipment's label and manual take priority over anything here. Read the full disclaimer.