Vaillant Sensor 0010033543

The Vaillant 0010033543 is a sensor used on Vaillant Arotherm PLUS /6 air-to-water heat pumps. It forms part of the appliance's temperature monitoring circuit, feeding readings back to the control board so the unit can regulate its output and defrost cycles correctly. It is a service component intended for replacement when the original sensor fails or drifts out of range.

• A fault code logged against a temperature sensor circuit on the heat pump controller.
• Temperature readings on the display that are clearly wrong, fixed, or implausible against actual system conditions.
• Short-cycling, where the unit starts and stops more often than it should.
• Defrost cycles that run too frequently, too long, or fail to complete.
• Reduced or erratic heating and hot water output with no other obvious cause.

• Confirm the model and variant from the appliance data plate, including the VWL number and revision.
• Check the part number against the manufacturer's parts list for your specific unit.
• Identify which sensor position has failed before ordering, as more than one sensor type may be used on the appliance.
• Inspect the sensor plug and wiring for damage, corrosion or poor connection before assuming the sensor itself is faulty.