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Mitsubishi Electric Mini-Split Code PA

Hard lockout

Forced compressor stop due to a water leakage abnormality. The unit saw the coil running far colder than room air for a total of 30 minutes AND the drain float switch underwater for more than 15 minutes, so it shut the compressor down. This state will not clear until main power is reset.

Manual wording: “Forced compressor stop (due to water leakage abnormality) ... Once the water leakage abnormality is detected, abnormality state will not be released until the main power is reset.”

Documented for: A-Control indoor units with a drain float switch and water-leakage detection

Likely causes, most common first

  1. Drain pump trouble
  2. Defective drainage - drain pump clogging or drain pipe clogging
  3. Open circuit of the float switch
  4. Contact failure of the float switch connector
  5. Dew condensation on the float switch, or drain water rippling because of a clogged filter
  6. Extension piping or connecting-wire mismatch on twin/triple/quadruple systems

What you can safely check yourself

  • Check the condensate drain line outside for a clog, kink, ice or debris
  • Remove and clean or replace the air filters - the manual lists filter clogging as a cause of the float switch tripping
  • Turn the system off at the breaker, wait one minute, and turn it back on once, since the manual says the abnormality is only released by resetting main power

When to call a technician

If PA returns after a power reset, the drain pump, float switch or piping is at fault. Call a technician before running it again - the unit stopped itself specifically to avoid a water leak.

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

Sources

Other Mitsubishi Electric codes