HVAC Code Lookup

Fujitsu Mini-Split Code 86

Soft lockoutShown as: OPERATION lamp blinks 8 times, TIMER lamp blinks 6 times, ECONOMY lamp blinking continuously

High pressure switch error, or on 42k and 48k units a pressure sensor error. The high pressure switch was seen open for longer than 10 seconds after power was turned on.

Manual wording: “High Pressure Switch Error - When the pressure switch is detected open for longer than 10 seconds after the power is turned on.”

Documented for: 18/24/30/36 models show high pressure switch error; 42/48 models show pressure sensor error. RGLX, RLS3/RLB/RLXB, RLF/RLF1

Likely causes, most common first

  1. System high side pressure genuinely too high (blocked condenser airflow, dirty coil, overcharge)
  2. Failed or open high pressure switch
  3. Wiring or voltage fault at the pressure switch

What you can safely check yourself

  • Clear leaves, snow, or debris away from the outdoor coil and fan so the unit can reject heat
  • Make sure nothing is stacked on or against the outdoor unit
  • Turn the power off at the disconnect for 3 to 5 minutes and back on

When to call a technician

Never jumper or bypass the high pressure switch - it is a safety device. Measuring switch voltage and resistance, or checking system pressures, requires a licensed technician with gauges.

A Fujitsu mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.

Source

Other Fujitsu codes