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LF30 Pressure Switch (40-800 Pa)
Product Details

The LF30 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.

The LFAS pressure cut-off switch is manufactured from selected compound derivatives of polycarbonate & PBT offering exceptional thermal and dimensional stability at elevated temperatures up to 105℃when used in contaminated atmospheres of air, products of combustion, L.P. or natural gas. It has been designed to meet the low pressure, high temperature specifications of future generations of fanned gas and similar appliances where differential pressures form part of an integral control systems.

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

Mounting /Fixing

4 screws with maximum penetration depth of6.3mminto appropriate mounting holes, or fixed with optional bracket.

Mounting Position

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.

Switch Differential

Not less than 0.1mb and not greater than 0.3mb depending on pressure settings.

Maximum Operating Pressure

10mbar Pmax=50mbar.

Operating Temperature Range


Electric Rating

125V,250V,5Asingle pole on-off or single pole change over. Other ratings are available on request.

Contact Arrangement



6.3 or4.88 mmmale 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

Calibration Tolerance

Standard production tolerance at ambient temperature is ± 0.10mb or ± 5% of set point, whichever is the greater.

Pressure Connections

6mmO.D. push on or "Permifix" tubing. The lower (negative) connector may be supplied in any one of four positions for ease of installation.

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