Sta-Rite Max-E-Therm Air Flow Switch, 42001-0061S

The Sta-Rite 42001-0061S is the air flow switch for the Max-E-Therm SR200, SR333 and SR400 pool heaters. It is a new, genuine OEM part.

What it does

The air flow switch sits in the heater’s electrical system and proves that the combustion blower is moving air. Only when it closes does the control let the ignition sequence go ahead. A switch that has failed or will not close leaves a heater that hums the blower but never lights, which is one of the more common Max-E-Therm complaints.

Fit

Because it is the factory part, it mounts and wires exactly like the switch coming out. It belongs to the same electrical group as the terminal board, transformer, ignition control module, thermistor and high limit switch, so if you are working through a no-ignition fault, those are the other parts to check.