Pentair 42001-0061S Air Flow Switch
The Pentair Master temp air flow switch (AFS) senses the pressure drop across the air metering orifice. ...

Used on the following models: MSTRTMP175LP MSTRTMP175NA MSTRTMP200LP MSTRTMP200NA MSTRTMP250LP MSTRTMP250NA Sta-Rite Max-E-Therm 400 LP Sta-Rite Max-E-Therm 400 NA SR400LP SR400NA Sta-Rite Max-E-Therm 200 LP Sta-Rite Max-E-Therm 200 NA Sta-Rite Max-E-Therm 333 LP Sta-Rite Max-E-Therm 333 NA Pentair MasterTemp 400 LP Pentair MasterTemp 400 NA SR200LP SR200NA SR333LP SR333NA Pentair MasterTemp 200 LP Pentair MasterTemp 200 NA Pentair MasterTemp 250 LP Pentair MasterTemp 250 NA Pentair MasterTemp 300 LP Pentair MasterTemp 300 NA MSTRTMP300LP MSTRTMP300NA MSTRTMP400LP MSTRTMP400NA Pentair MasterTemp 175 LP Pentair MasterTemp 175 NA

The heater requires a gas supply of not less than 4" (10.2cm) wc and not more than 14" (35.6cm) wc. Gas supply
pressures outside of this range may result in improper burner operation. A minimum flowing or dynamic inlet pressure
(while the heater is running) of 4" (10.2cm) wc is required to maintain input rating with no more than a 2” pressure drop
between static and dynamic. The gas supply must be installed in accordance with the National Fuel Gas Code,
ANSIZ223.1, or standard CSA B149.1, Natural Gas and Propane Installation Codes, as applicable and all applicable
local codes. Install a manual shut-off valve and a sediment trap and union located outside the heater panels, see Figure 6.
Do not use a restrictive gas cock.