Café Leaked After Install: Drain Line Pitched Wrong

A cafe leaks from an installation that has never drained properly. Whether the unit is faulty or was never able to work.

By Team Snowflake | Updated 24 Aug 2026

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

How this presents

Water at a newly installed unit within days of first use. The drain run is neat and the pipework looks correct. Nothing has ever drained away properly from it.

Setup: LG Wall-mountedNew installF&BMarina East
Misread as: A faulty new unit, on an installation that has never drained properly.
Check first: Whether water sent down the line reaches the outlet with the run still open

What else produces this

A drain that has never worked is a commissioning question, not a fault. The fastest way to settle it is to send water down the line. A level held against the pipe measures one short section at a time and misses a dip between two of them. Water finds every low point at once, in the order the water itself meets them, which is exactly the information nobody else can supply.

A run that has never drained properly places the fault at the installation rather than at anything since.
Neat pipework and a plausible appearance explain why it passed whatever check it was given.
A section pitched the wrong way holds water rather than passing it along the run.
Water sent down the line stopping at that section confirms it without any measuring at all.

Why it happens

Condensate moves under gravity and nothing else. A section pitched against the fall holds whatever reaches it, and once that section is full the water backs up to the unit and comes out where it can. The rest of the run may be perfect, which is why a visual check and even a spot measurement both pass. Only water travelling the whole length exposes the one section that is wrong.

What resolution involves

The section is re-pitched to fall the whole way and the line proven again with water before anything is closed up. That order matters: prove first, make good second. A drain closed into trunking or above a ceiling before it is tested is a drain nobody will look at again until it leaks.

How to tell it worked

Water sent in at the unit and watched leaving at the outlet, with the run still open to view. Any point where it slows, stops or stands is a section still pitched wrong, and it is visible only while the pipe can be seen.

Before you approve a quote

Prove a new drain with water before closing it up

Gradient is the only thing making a drain work. Appearance and spot measurements both miss a dip.
Water finds every low point at once, in the order it meets them. Nothing else tests the whole run.
Prove first, make good second. A drain closed in untested is one nobody sees again until it leaks.

Questions this case answers

Why is a brand new aircon leaking within its first month?

Because a level measures one short section at a time. A dip between two measured points passes both checks, and the pipe can look entirely neat while holding water somewhere along its length.

What does a wrongly pitched drain line actually do?

It holds water. A section pitched against the fall collects whatever reaches it until it fills and backs up to the unit, which then leaks. The rest of the run can be perfectly neat, which is why only water travelling the whole length exposes it.

New install dripping: is a warranty replacement the answer?

Not for this. Nothing has failed and no part is defective: a section of the new drain run was pitched against its fall, so it holds water and backs up to the unit. Re-pitching that section and proving the run with water is the repair.

What should an installer be asked to confirm about drainage?

That the whole run has been proven with water before it is closed up. Water sent in at the unit must be watched leaving at the outlet with the run still open to view, because appearance and spot measurements both miss a dip.

Describe your situation

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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