Applies to: Next-Gen testo 300, matching the pictured outlet.
Before you start: Stop the pump. Acidic condensate requires acid-resistant gloves, eye protection and protective clothing. Keep liquid off skin and housing.
Open the outlet
Open the trap’s sealing plug as illustrated.

Drain the trap
Hold the outlet downward and drain into a suitable container.

Close the seal
Wipe remaining drops and close fully. A leaking seal can distort readings.
If the issue continues: If the plug will not seal or liquid has entered the housing, stop using the device and tell QRM what happened.
Still need help with your device?
Include the model, serial number, exact error and checks already completed.
Source and applicability
Next-Gen testo 300 - Combustion Analyzer: Instruction Manual — §10.5, pp. 82–83; safety §3, p. 8. 0970 3010 en 07 - 11.2022
Open the complete Testo operating manual ↗ · Find this model in the manual list
QRM wording summarizes the checks. Diagram excerpts © Testo SE & Co. KGaA. Follow the complete manual and warnings for your instrument. Source checked 7 September 2026.
