Concealed Unit Dripping from the Panel: Drain Pump Seized

A concealed ceiling unit drips from its access panel. Whether the pump has failed or merely stopped turning decides how big the job becomes.

By Team Snowflake | Updated 24 Aug 2026

Teaching case based on recurring Snowflake service patterns; identifying details are combined.

How this presents

Water backing up above a ceiling and finding its way through, from a unit whose pump is no longer moving anything at all. The pump is receiving power. Nothing about the installation has been altered or worked on.

Setup: Mitsubishi Electric Ceiling-concealed10-12 yearsCondoNovena
Misread as: A pump that is finished and needs replacing, on equipment sitting well out of easy reach.
Check first: The condition inside the pump chamber, before anything electrical is tested

What else produces this

A pump with power that does not move water separates the supply from the mechanism, and on this type of pump the mechanism is where the trouble lives. Opening the chamber is a short job and it answers the question directly. Scale and growth accumulate on every wetted surface, and a rotor packed with that deposit stops turning while the motor tries. Testing the electrics first is the longer route to the same answer.

Power reaching the pump while nothing moves places the fault at the mechanism rather than the supply.
Scale and growth packed inside the chamber account for a rotor that will not turn.
A motor that runs freely once the chamber is cleared confirms nothing electrical has failed.
Warm still water standing in the chamber between cycles explains why the deposit forms there at all.

Why it happens

Condensate carries whatever has been washed off the coil, and a pump chamber holds a little of it permanently. Warmth, moisture and stillness let scale and growth establish on every surface inside, including the moving parts themselves. The build-up is gradual, so the pump slows well before it stops, and by the time water appears above a ceiling the chamber has been closing up for months.

What resolution involves

The chamber is opened and cleaned rather than the pump replaced, and it goes onto a cleaning schedule from then on. This is the part usually missed. A condensate pump is a maintenance item rather than a fit-and-forget one, and on concealed equipment it is the component most likely to cause visible damage when it is left alone.

How to tell it worked

Water poured into the tray to see the pump start promptly and clear the tray fully. A pump that starts late or empties slowly is still partly obstructed, and it will back up again before long.

Before you approve a quote

The pump chamber fouls long before the motor fails

A pump with power that moves nothing has a mechanical problem. Open the chamber before testing electrics.
Condensate is not clean water. Everything washed off the coil settles where the pump sits.
Treat the pump as a maintenance item. On concealed equipment it is what causes visible damage.

Questions this case answers

Water dripping from a ceiling aircon panel: is it a refrigerant leak?

Drainage is the far more likely answer, and a gas check settles it quickly. Condensate carries whatever has been rinsed off the coil, including dust, biological growth and dissolved minerals, all of which settles wherever the water sits still. A pump chamber is exactly such a place.

Why does the water seem to come from several places at once?

Because it spreads before it escapes. Once the tray overflows, water runs across the top of the panel and drips wherever it finds a gap, so one fault looks like several.

Is a seized drain pump worth cleaning instead of replacing?

Frequently, yes. Where the deposit has seized the rotor, clearing the chamber restores the pump, and replacement is only needed once the motor or the switch has genuinely failed.

What makes a condensate pump stop working?

Scale and algae build up inside a warm, damp chamber until the impeller locks against the wall. Water then backs up above the ceiling until it finds a way through, which usually means damage to finishes rather than a visible drip at the unit. That is why a concealed pump is worth more attention than an accessible one.

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Tell us what’s going on. Symptoms, setup, photos, anything we should know. We’ll assess and come back with the right next step.

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