The LFAS employs a differential pressure to actuate a precision snap switch at chosen pressure setting. This may be the difference between atmospheric and a negative or positive pressure or between any two given pressures. When a change of pressure occurs between the negative pressure chamber and the positive pressure chamber the main diaphragm activates the snap switch at a pre-determined value.
Typical Applications: Detects air flow in forced draught appliances Signals either positive, negative or zero air movement Shut down burner in blocked flue conditions Guards against poor or hazardous combustion Indicates dirty or inefficient filters
Air , products of combustion, L.P. or natural gas
4 screws with maximum penetration depth of 6.3mm into appropriate mounting holes, or fixed with optional bracket.
The LFAS is position sensitive. It may be mounted in most positions provided it has been calibrated.
Field Adjustable Range
0.4mbar to 8.0mbar make on positive or negative pressure rise. Minimum upper switching pressure 0.4mbar. Minimum lower switching pressure 0.2mbar.
Not less than 0.1mb and not greater than 0.3mb depending on pressure settings.
Maximum Operating Pressure
Operating Temperature Range
105 C Maximum
125V,250V, 5A single pole on-off or single pole change over. Other ratings are available on request.
SPDT or SPST
6.3 or 4.88 mm male Q.C. Optional insulation cover available as necessary.
LFAS switches are normally calibrated at their lower switching pressure in accordance with customer requirements. Ramp rate at switch point=0.03mb/second
Standard production tolerance at ambient temperature is ± 0.10mb or ± 5% of set point, whichever is the greater.
6mm O.D. push on or "Permifix" tubing. The lower (negative) connector may be supplied in any one of four positions for ease of installation.