Description

The Swimables SW-41-024 is an aftermarket stack flue sensor for MasterTemp and Max-E-Therm pool heaters. It replaces the original stack sensor in the same position.

What the stack sensor does

The stack sensor sits in the exhaust path and reports flue temperature back to the heater control board. That reading is a safety input. If the exhaust runs hotter than the heater is designed for, the board shuts things down before damage happens. A sensor that has failed sends a reading the board will not accept, and the heater locks out even though nothing else is wrong.

Aftermarket, not factory

This is a Swimables part rather than the manufacturer sensor. It is the lower cost route to the same repair. The genuine sensor is available separately if you would rather stay with the factory component.

Before you order

Check the connector and wiring first, since a corroded or loose plug produces the same fault as a dead sensor. This listing covers the stack flue sensor alone. Thermistors, high limit switches and control boards for these heaters are separate parts.