TSI Instruments Certifier Plus - Page 26

3-4 
9. Perform testing per the device manuf The
manufacturer of the device under test will specify the testing requirements and pass/fail criteria.
Test circuit for bi-directional flow
NOTICE
If using a test lung with a built-in restrictor or a separate restrictor, connect the airway pressure
fitting with less than 15 cm length of the 22 mm tubing between the restrictor and the flow
module. If this is not done, the flow direction sensor may not work properly.