Testo 420 Differential Pressure Measuring Instrument

Experience the pinnacle of HVAC system testing with the Testo 420 Differential Pressure Measuring Instrument. Designed for professionals, this versatile tool allows for straightforward, effective tests on filters and highly accurate flow measurements in ventilation ducts when paired with an optional Pitot tube.

Your Advantages

• High Precision Testing: Excels in differential pressure measurement up to 120 Pa, making it perfect for checking filter status in commercial HVAC units.
• Volume Flow Calculation: When paired with an optional Pitot tube, it accurately calculates flow velocity and volume flow based on easy duct geometry inputs.
• Effortless Data Management: Store measurement data directly on the device and transfer it to your PC via plug-and-play USB connectivity—no extra software required!
• Clear Visibility: A large, illuminated dot matrix display and intuitive menu guidance keep your workflow fast and error-free.

What It's For & Who It's For

Applications (What It's For)

This instrument is an essential component for assessing commercial ventilation systems. It is primarily used for monitoring pressure drops across heavily used air filters and, when connected to a Pitot tube, measuring precise airflow velocities inside complex ductwork setups. It also features absolute pressure measurements for a complete diagnostic overview. For a full walkthrough on getting accurate readings in the field, see our step-by-step measurement guide.

Who It's For

Built specifically for commercial HVAC balancers, NEBB-certified technicians, facility managers, and ventilation engineers who require a reliable, multi-functional tool for duct and filter assessments.

Tradie Pro Tip: When checking massive commercial air handler filters, the automatic zeroing feature on this unit is a game-changer for low-pressure accuracy. Don't forget—if you're doing duct traverses, pair this with a solid Pitot tube to get timed and multi-point mean calculations instantly processed right on the screen!

Delivery Scope

1 x Testo 420 differential pressure measuring instrument (Product no. 0560 0420), including batteries and calibration protocol.

Technical Data