New Unit Drips After First Service: Drain Pan Not Reseated
A new unit drips after its first service. Water escaping at the unit rather than downstream of it points somewhere specific.
By Team Snowflake | Updated 24 Aug 2026
Teaching case based on recurring Snowflake service patterns; identifying details are combined.
How this presents
Water appearing below a recently serviced unit that had never leaked before. The drain line is clear along its length. Water escapes at the unit itself rather than anywhere along the run.
- Setup
- Mitsubishi Electric Wall-mountedNew installHDBTengah
- Misread as
- An obstruction in a brand-new installation, suggesting something is wrong with the equipment.
- Check first
- Whether the pan sits flush against the coil housing along its whole edge
What else produces this
Water escaping at the unit rather than along the line separates a collection problem from a removal problem, and they need different work. A clear drain proves removal is fine. What remains is whether the water is reaching the outlet in the first place, which depends on the pan sitting flush against the coil housing. A gap of a few millimetres at the wrong edge is enough for water to run behind the pan instead of into it.
A clear drain line along its whole length confirms removal is working correctly.
Water escaping at the unit rather than along the run places the fault at collection instead.
A pan not seated flush against the coil housing leaves a path for water to pass behind it.
No leak before the unit was last opened dates the change to that work rather than to the equipment.
Why it happens
The pan is positioned so that every drop leaving the coil lands inside it. Reseating it slightly out of position, or leaving a clip unfastened, opens a small gap along one edge. Water follows the coil surface down and past that gap rather than into the pan, so most of the water is caught and the rest goes into the casing. The drain is never involved at all.
What resolution involves
The pan is reseated flush and secured, which resolves it completely with no parts and no clearing. The transferable point is where to look: water escaping at the unit is a collection fault and water backing up along the run is a removal fault. Those are different jobs, and knowing which one is in front of you saves opening a line that was never the problem.
How to tell it worked
Water poured across the coil face and watched into the pan, at both ends rather than the middle. A pan that catches at one end and misses at the other is still out of position.
Before you approve a quote
Escaping at the unit is collection, not removal
- Water at the unit is a collection fault. Water along the run is a removal fault. Different jobs.
- A pan a few millimetres out of position sheds water behind itself rather than into the outlet.
- A clear drain line and a leaking unit together point at the pan, not the pipe.
Questions this case answers
New aircon started dripping after its first service: is the unit faulty?
Water dripping from the front of the indoor unit: where is it coming from?
Do I need a warranty claim for a leak on a unit under a year old?
Why does the drain pan come out during a service at all?
Ready to get started?
Tell us what’s going on. Symptoms, setup, photos, anything we should know. We’ll assess and come back with the right next step.