Samsung Heat Pump Error Code P466

P466 indicates an indoor unit floating switch error on first detection, specific to cassette-type indoor units with a drain pump. The float switch in the condensate drain pan has signaled that water has reached a high level or that the switch circuit is reading incorrectly. The system generates this code as an early warning to prevent overflow before conditions worsen.

Continuing to operate the unit with an active P466 error is not recommended. If the condensate pan is genuinely full and the drain pump is not clearing it, water can overflow and cause ceiling or structural damage. The float switch exists as a protective device, and ignoring the alert risks water damage beyond what a repair would cost.

A power reset may temporarily clear the P466 code, but it will return if the underlying cause has not been resolved. Because this is a first-detection warning tied to an active sensor condition, the code will reappear as soon as the float switch reads open again during normal operation. Address the drain system issue first before resetting the unit.

Some causes of P466 are accessible to a knowledgeable DIYer. Clearing a clogged drain line by flushing it with water or compressed air is a common self-serviceable fix. However, testing float switch resistance, diagnosing the drain pump, or tracing wiring faults requires electrical measuring tools and familiarity with the cassette unit's internal layout, so those steps are better handled by a qualified technician.

Repair costs depend on the root cause. Drain line cleaning is typically the least expensive fix, often in the range of $75 to $150 for a service call. Replacing a faulty float switch or drain pump will generally run between $150 and $400 depending on parts and labor rates in your area. More complex wiring or control board issues can push costs higher.