Swimables Air Flow Switch For Pentair MasterTemp And Max-E-Therm Heaters | 42001-0061S | SW-41-061

The Swimables air flow switch (AFS), which senses the pressure drop across the air metering orifice. The air flow switch (AFS) senses the pressure drop across the air metering orifice. As soon as there is sufficient air flow, the AFS closes, closing the circuit to the hot surface igniter (HSI), which ignites the fuel mixture. On a call for heat, the blower and HSI are energized. In about 20 seconds, the gas valve opens and ignition occurs. The HSI then switches to a sensing mode and monitors the flame.