We occasionally get questions about how to do differential and static pressure testing with the TSI VelociCalc 9555 and 9565 air velocity meters. It's actually pretty simple.
For differential pressure testing:
- Connect the two lengths of neoprene tubing to the positive and negative ports at the top of the instrument
- Place the free end of the positive port tubing in the area being tested
- Place the free end of the negative port tubing in the control/ambient zone
- A positive reading means the variable/sample (+) zone is higher pressure than the control/ambient (-)
- A negative reading means the control/ambient zone (-) is higher pressure than the variable/sample (+) zone
For static pressure testing:
- Connect one length of neoprene tubing to the positive port at the top of the instrument
- Keep the negative (-) port open to measure ambient conditions
- Attach the static pressure tip to the tubing on the positive (+) port
- Point the static pressure tip directly into airflow to get an accurate reading
- Positive reading means the pressure in the duct is higher than the measured ambient conditions
- Negative reading means the pressure in the duct is lower than the measured ambient conditions
For more tips on using the VelociCalc 9565, go here.