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Leaky Mini-Split - 5 Quick Reasons Why

Leaky Mini-Split - 5 Quick Reasons Why

Jon Hubal
3 minute read

Having a ductless mini-split system is excellent! Until you have a leak…if you have a leaky mini-split - here are 5 quick reasons why!

If your unit is leaking water, that is definitely caused for concern. There are a few likely suspects as to why that is worth checking. The good news is the fix might be more straightforward than you think, saving you hundreds versus calling a pro. We'll help you diagnose your leaky mini-split system with the top five most common culprits to this problem.

5 Reasons for Leaky Mini-Split 

Reasons for Mini-Split Leaking

1) A Blocked Drain Line

A clogged drain (or condensate) line is the most likely answer. As interior units (evaporators) pull moisture from the air, the drain line transports the accumulated water in the drain pan to the outdoor unit. If the line becomes clogged, the drain pan will start to overflow. If this is the case, the mini-split missed spring cleaning, and you're probably overdue for maintenance. But hey, aren't we all?

Mini-Split Blocked Drain Line

2) Damaged Drain Pan

Drain pan damage is the second most common reason for your leaky mini-split. Even though they're designed for it, drain pans take a corrosive beating from the constant water contact. This causes them to rust and degrade over time, eventually leaving holes in them. Also, most drain pans are as old as the system itself, and the material they're made of may break down and become weak or brittle. Any wear and tear over the years can cause leak vectors. You may need to contact the manufacturer to replace it.

3) Dirty Air Filter

Dirty Mini-Split Air Filter

A dirty filter is dangerous to air quality and system efficiency and can even cause your unit to leak water. A saturated filter causes particles to collect on the evaporator's coils – blocking airflow and freezing the coils. When the frozen coils regain warmth, the ice melts, causing water to drip. The easy solution here is to clean or replace the filter. 

4) Condensate Pump

Some mini-splits have a pump for the drain pan to help it along. If the pump is defective or damaged, water will start leaking from the indoor air handler. The fix here is to replace or fix the pump, likely by contacting the manufacturer. It may require a professional to fix or install unless you are confident in your mechanical skills.

5) Refrigerant Line

Like dirty air filters, being low on refrigerant causes the evaporator coils to freeze. When they melt, the amount of water released is often more than the drain and evaporator can manage – causing a leaky mini-split. On the bright side, it is still water, but a problem nonetheless. It's recommended to have a professional replace the freon (refrigerant) since it has acidic properties and can be dangerous to your health.

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