Product Overview
Adjustable Paddle Airflow Proving Switch for HVAC Ducts - Intec DBSL-1EPL-4-US
Product Condition
Unused. No box. No testing performed. Clean unit with stainless steel paddle. Visual inspection only.
Carefully packed and shipped same business day from our Idaho warehouse. Online since 1999. Honest equipment and straightforward service.
Product Overview
Intec DBSL-1EPL-4-US duct air flow switch designed for on-off monitoring of airflow in ducts carrying air or non-aggressive gases. The unit uses a stainless steel paddle sensing element and internal micro switch to provide single-stage switching. Adjustable via internal screw, the device allows field setting of flow cut-in and cut-out thresholds within its rated velocity range. Available with one or two SPDT outputs rated up to 24/250 VAC at 15 (8) A, and housed in NEMA 1 or NEMA 4 enclosures with IP40 or IP65 protection depending on configuration. This style of mechanical airflow proving switch remains common in HVAC, air handling, and industrial ventilation control circuits.
Key Features
- Model: DBSL-1EPL-4-US
- Operation: On/Off, single-stage micro switch
- Output: 1 or 2 SPDT, 24/250 VAC, 15 (8) A
- Adjustable flow setpoint via internal screw
- Cut-out range: 197 to 1,575 ft/min (1.0 to 8.0 m/sec)
- Cut-in range: 492 to 1,811 ft/min (2.5 to 9.2 m/sec)
- Paddle size: 3.2 x 6.9 in. (80 x 175 mm)
- Paddle with level length: 7.9 in. (200 mm)
- Paddle material: Stainless steel; level material: Brass
- Housing: Galvanized steel base, ABS fire-retardant cover
- Protection: NEMA 1 (IP40) or NEMA 4 (IP65)
- Ambient temperature: Housing -40°F to 185°F; paddle 14°F to 185°F
- Humidity: 10 to 90% RH, non-condensing
- Wiring: Terminal with retaining screws, max 14 AWG (2.5 mm²)
- Cable entry: M20 fitting, replaceable with 1/2 in. conduit connector
- Dimensions: 4.3 x 2.8 x 2.8 in. (108 x 70 x 72 mm)
- Installation: Duct mounted
Applications
- HVAC supply and return duct airflow proving
- Fan status interlocks
- Air handling unit protection circuits
- Industrial ventilation airflow monitoring
- Filter blockage detection through airflow loss
- Building automation safety shutdown circuits
Frequently Asked Questions
What flow velocity range can this switch detect?
Cut-out range is 197 to 1,575 ft/min (1.0 to 8.0 m/sec). Cut-in range is 492 to 1,811 ft/min (2.5 to 9.2 m/sec), adjustable via internal screw.
What is the electrical contact rating?
The micro switch is rated 24/250 VAC at 15 (8) A and is available with one or two SPDT outputs depending on configuration.
What environmental conditions is it rated for?
Housing temperature range is -40°F to 185°F. Paddle temperature range is 14°F to 185°F. Permissible humidity is 10 to 90% RH, non-condensing.
What wiring does it support?
Terminal connections accept up to 14 AWG (2.5 mm²) conductors with retaining screws. Standard cable entry is M20, replaceable with 1/2 inch conduit.
Is it suitable for outdoor or washdown areas?
With a NEMA 4 (IP65) housing configuration, it is suitable for environments requiring protection against dust and water ingress.
Airflow proving does not require complexity—just a clear threshold and a reliable contact. A mechanical paddle in the duct, a signal in the circuit, and the system responds accordingly.
