Mitsubishi mini-split drain pump assembly
Part: model-specific lift pump
Primary replacement part when P5 returns and the pump winding is open or the impeller is seized.
$90-$220
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Mitsubishi P5 Error Code - What It Means
Mitsubishi error code P5 indicates a drain pump fault. The control board commanded the condensate pump but did not see the expected water-level response. This code is common on cassette, ceiling-concealed, and some ducted Mitsubishi indoor units that use a lift pump.
Common Causes
- Failed drain pump motor - The pump winding is open or the motor is seized.
- Pump impeller jammed - Slime or debris has locked the impeller.
- Float switch not resetting - The pan switch still reports high water even after pumping.
- Blocked discharge tube - The pump runs but water can’t leave the unit.
Drain Pump Fix Sequence
- Turn off power to the indoor unit.
- Access the drain pump assembly and inspect for standing water.
- Disconnect the discharge tube and verify it is open.
- Remove the pump and inspect the impeller for slime or debris buildup.
- Test the pump winding with a multimeter for continuity.
- Replace the pump if the winding is open or the motor hums without moving water.
- Verify the float switch resets once the pan is empty.
Parts Often Needed
| Part | Notes |
|---|---|
| Drain pump assembly | Model-specific Mitsubishi part |
| Float switch | Often sold separately |
| Discharge tubing | Replace if kinked or brittle |
Technician Tips
Do not keep running the indoor unit with a P5 fault. A failed pump or stuck float switch can overflow the condensate pan and stain ceilings, walls, or equipment below the cassette.
If the pump runs but the pan does not empty, clear the discharge tube before replacing parts. If the pump does not run at all, verify power at the pump plug and test the winding for continuity before ordering a model-specific pump assembly.
Focused Parts Searches
Before ordering, match the drain pump, float switch, or tubing to the indoor unit model, voltage, connector style, and fault symptom.
- Mitsubishi P5 drain pump assembly
- Mitsubishi mini-split condensate float switch
- Mini-split condensate drain tubing
When to Call a Pro
If the pump receives power but still doesn’t run, or if the fault involves concealed piping in a ceiling, call a Mitsubishi-trained service tech to avoid water damage.