Frozen defrost drain: why ice accumulates at the base of the outdoor unit

Water produced during defrost must be drained quickly. If it remains at the base, it can refreeze and create a continuously growing mass of ice.

Clogged holes

Leaves, dirt, or ice can restrict drainage.

Incorrect tilt

If the unit is not properly installed, water may pool.

Base pan heater

In cold climates, a base pan heater helps keep the drainage area free.

Risk

Ice can reach the coil or the fan and seriously affect operation.