Shop unit dripping near closing time: drain pump float was jammed
A Bukit Merah shop unit only started dripping late in the day, after hours of operation. That timing pointed to accumulated water and pump behaviour, so the drain pump float was checked before assuming a cracked tray or major leak.
By Team Snowflake | Reviewed 15 Jun 2026
Case summary
Daikin Cassette9 years oldRetailBukit Merah, Singapore
- Concern
- Customer worried the tray was cracked because water appeared above the retail floor.
- Found
- Drain pump float jammed by sludge after long shop runtime
- Key check
- Checked pump float movement after recreating late-day water load
- Result
- The unit stopped dripping after the float and pump chamber were cleared. The shop avoided unnecessary tray work and had a better runtime-based cleaning interval for future maintenance.
What we were told
The shop unit did not drip in the morning. Water appeared near closing time and landed close to display stock. Staff had wiped the panel dry several times, but the leak returned after the shop had been running for most of the day.
What we checked
The time pattern made this different from a constant cracked tray leak. We checked the drain pan, pump chamber, float movement, and water outlet path after allowing enough water to collect. For a shop unit, the useful test is not just whether it leaks immediately; it is whether the pump clears water after long runtime.
The panel and tray were not cracked at the visible leak point.
Water level rose in the pump chamber after extended operation.
The float movement was sticky and did not trigger clearing consistently.
Sludge was present around the pump chamber and float hinge.
What we found
The pump float was jammed by sludge. Early in the day, the water load was low enough that the problem stayed hidden. Near closing time, accumulated water reached the point where the pump should have cleared it, but the sticky float did not respond consistently. The water then backed up and found the easiest path out of the cassette panel. The late-day pattern was the giveaway: the cassette was not leaking from the first minute, so the fault was linked to water accumulation and pump response.
What fixed it
We cleaned the pump chamber, freed the float movement, cleared the drain path, and checked that water left properly after the chamber filled. The advice was to keep cassette drainage on a service schedule that reflects shop runtime, not just calendar age. We did not quote tray replacement because the tray was not the source of the leak. Staff were also told to report the first drip time, not only the leak location.
Outcome
The unit stopped dripping after the float and pump chamber were cleared. The shop avoided unnecessary tray work and had a better runtime-based cleaning interval for future maintenance.
What this case teaches us
Late-day drips often need load timing recreated
- A leak that appears only after long runtime may not show during a short inspection. The drain system has to be checked under enough water load.
- Shop units run longer than home units, so pump floats and drain pans can expose faults near closing time.
- Tell the technician when the drip starts. Morning drips, instant drips, and closing-time drips point to different checks.
Related reading
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