Diaphragm pressure switch LF35

differentialSPDTfor air

Product overview
The LF35 are general-purpose airflow proving switches for HVAC and energy-management applications. They detect positive, negative or differential air pressure and monitor blocked filters and fan suction in ducts, pipes and tunnels.

Parameters
Model: LF35-1; LF35-2
Media: Air
Mounting position: diaphragm in any vertical plane
Field-adjustable range: LF35-1: 0.5 ±0.05 mbar to 30.0 mbar; LF35-2: 0.2 ±0.05 mbar to 5.0 mbar
Switch differential: LF35-1: progressive ~0.05 mbar (min) to ~2.0 mbar (max); LF35-2: progressive ~0.05 mbar (min) to ~0.25 mbar (max)
Maximum pressure: 30 mbar
Operating temperature: -40 ℃ to 82 ℃
Electrical rating: 300 VA pilot duty at 115–277 VAC, 10 A non-inductive
Connection: ferrule-and-nut compression connectors for 0.25" OD rigid/semi-rigid tubing; optional 0.25" male slip-on connector
Contact arrangement: SPDT

Conversion note
1 mbar = 100 Pa; 1" W.C. ≈ 249 Pa

Features

• Two calibrated ranges (LF35-1, LF35-2) to cover common HVAC detection needs
• Connection options for rigid/semi-rigid or flexible tubing (0.25")
• Mounting bracket options (A or B) and optional wire protection on enclosure
• Progressive switching differential for predictable actuation

Applications

• Airflow monitoring in HVAC ducts and tunnels
• Blocked filter detection
• Fan suction and ventilation monitoring
• Energy management and ventilation control systems

Technical specifications

• Models: LF35-1, LF35-2
• Medium: air
• Switch output: SPDT, pilot duty up to 300 VA (115–277 VAC), 10 A non-inductive
• Mounting: diaphragm may be positioned in any vertical plane
• Connection types: 0.25" OD ferrule & nut compression; 0.25" male slip-on option
• Operating temperature: -40 ℃ to 82 ℃
• Maximum pressure: 30 mbar