HVAC Code Lookup

Fujitsu Mini-Split Code 53

WarningShown as: OPERATION lamp blinks 5 times, TIMER lamp blinks 3 times, ECONOMY lamp blinking continuously

Drain pump error. The condensate float switch has stayed made for more than 3 minutes, meaning water is backing up in the drain pan.

Manual wording: “Drain Pump Error - When the float switch is on for more than 3 minutes, error will trigger.”

Documented for: RLF series, RGLX series, LUAS1 series ducted and cassette indoor units fitted with a condensate pump

Likely causes, most common first

  1. Clogged condensate drain hose or drain line
  2. Float switch fouled with dust or debris, or stuck
  3. Failed condensate pump
  4. Loose or pinched float switch connector (CN9) or wire
  5. Failed indoor controller PCB

What you can safely check yourself

  • Check the condensate drain line outside for a blockage, kink, or ice at the discharge point
  • Check that the drain hose has a continuous downward slope and is not crushed
  • Turn the unit off at the breaker until the pan has drained, then restore power

When to call a technician

Clearing a plugged drain inside the unit, testing the float switch, or replacing the pump means opening the indoor unit. Get a technician if the outside end of the drain line is clear.

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

Sources

Other Fujitsu codes