Samsung Air Conditioner Error Code E153

The Samsung E153 error code indicates an indoor unit float switch error. Specifically, the float switch has remained in the open position for longer than one continuous minute, which signals to the control board that either the drain pump has failed or the drain water level inside the unit has risen high enough to trigger overflow protection. This error is specific to cassette-type indoor units, which use a float switch as part of their condensate management system to prevent water from spilling into the occupied space below.

The float switch is a safety device mounted inside the condensate drain pan. Under normal operation, condensate water is pumped out continuously and the float remains in the down position, keeping the switch closed. When drain water accumulates faster than it can be removed, or when the drain pump stops functioning, the water level rises and lifts the float, opening the switch circuit. The control board monitors this signal and triggers E153 after the switch has been open for 60 seconds or more, indicating the condition is not a momentary fluctuation.

Diagnosing this error begins by confirming the unit is a cassette type, then measuring the resistance across the float switch terminals. A properly triggered float switch will read infinity (open circuit), confirming the switch itself is functioning and that the fault lies with the drainage system or pump. If the float switch reads a closed circuit (near zero resistance) while the error is active, the switch or its wiring may be faulty. Causes range from a clogged drain line restricting flow, a failed drain pump motor, to a pump capacitor or wiring issue preventing pump operation.