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Mitsubishi Electric Air Conditioner PA Error Code
Shut down to prevent a water leak. Here is what it means and how to clear it, easiest fix first.
The system has forced the compressor to stop because the indoor unit detected a water-leak condition. On units with a built-in drain pump, that points to the condensate drain system.
These check codes appear on wired wall controllers, mainly with P-series, Mr. Slim and ducted or ceiling units; wall-mounted M-series units (MSZ) usually report faults by blinking the OPERATION light instead. The meanings here come from Mitsubishi Electric's Mr. Slim code list for Singapore models, and they can differ by series and region, so check your manual. PA is listed in the Singapore Mr. Slim code list but not in the North American controller manual.
How to fix Mitsubishi Electric PA
Switch off and look for water
Switch off the breaker and check under the indoor unit for dripping or wet ceiling tiles. Keep clear of any wet electrical fittings.
Clear the drain line outlet
Clear any blockage you can reach at the open end of the condensate line outdoors or at the floor drain.
Reset the power at the breaker
Switch off the breaker that feeds the air conditioner (some systems have separate breakers for the indoor and outdoor units, so switch off both). Wait about five minutes, switch the power back on and restart the unit to see if the code clears.
When to call a technician
If PA returns or there's visible water damage, have a technician clear the internal drain and check the pump.
Parts that commonly cause PA
- drain pump
- condensate drain line
- drain pan
Order parts by your exact model number so they fit.
Other Mitsubishi Electric air conditioner codes
- Blinking OPERATION lightWall unit's indicator light is flashing
- P1Room air temperature sensor fault
- P2 / P9Indoor coil temperature sensor fault
- P4 / P5Drain sensor or drain pump problem
- P6Freeze or overheat protection
- P8Pipe temperature error
- PbIndoor fan motor error
- FbIndoor control board error
- E0-E5Wall controller communication error
- E6 / E7 / E9Indoor and outdoor units aren't communicating
- U1 / UdHigh pressure or overheat protection
- U2Discharge temperature too high or low refrigerant
- U3 / U4Outdoor temperature sensor fault
- U6 / UP / UFCompressor overcurrent
- U8Outdoor fan stopped
- U9 / UHPower supply or current sensor problem
- PLRefrigerant circuit abnormal
Frequently asked questions
What does PA mean on a Mitsubishi Electric air conditioner?
The system has forced the compressor to stop because the indoor unit detected a water-leak condition. On units with a built-in drain pump, that points to the condensate drain system.
Can I fix Mitsubishi Electric PA myself?
Often. The first steps above are safe checks a homeowner can do. If they don't clear PA, the cause is likely a worn part that needs replacing.
What if PA keeps coming back?
A code that returns after a reset and the checks above usually means a part is wearing out. Note when PA appears (which cycle, how often) and have your model number ready; it helps a technician bring the right part on the first visit.
Last reviewed 2026-10-19. Codes and steps can vary by model; check your owner's manual.