What happens
Water cannot leave the intended path because of an obstruction, routing defect or incorrect cabinet mounting.
Typical symptoms
Water alarm, dripping or backup in a wall-mounted, ceiling or stack unit.
Checks that distinguish this cause
Use the specific cabinet’s drainage diagram and inspect the installed route, pan and connections after safe isolation. Evaluate the documented drain test in the relevant mode.
What can look similar
External condensation or thawing ice can create water without a blocked drain.
Repair direction
Repair the established route or mounting defect with approved fittings and methods.
Verify the repair
Verify water removal and leak-free operation in the required modes.
Equipment-specific limits
Determine cabinet orientation, operating mode and accessory presence first. Condensate evaporators, nebulizers and other disposal systems are optional and have their own instructions; do not assume every AIO has one.
Practice this diagnosis
This cause is a reference topic; it does not yet have a dedicated simulated call. Browse the practice board.
References and applicability
Original HVACSim explanations with manufacturer and instrument-maker references for further reading. These resources support the subject; their model-specific examples are not specifications for every system.
- INNOVA (formerly Ephoca): AIO technical resourcesChoose cabinet style, generation and accessories. Installation, maintenance and troubleshooting documents are separate.
- Olimpia Splendid: Unico product literatureArchitecture and product selection; obtain the actual Unico installation and service manual for diagnostic limits.
Editorial review: 2026-09-29. Verify the current manual for the installed model.