M&C PSS Series Instruction Manual page 23

The following minimum gas flow rates result from the requirement
of the maximum pressure-side load of the sample gas pumps:
N 5 KPE approx. 100 l/h air.
Note
If the required minimum total flow rate is not reached, excessive
overpressure can lead to premature destruction of the pump
diaphragm.
For long-term measurements with a high dust content in the sample
gas, a suitable gas sample probe must be provided to protect the
sample line from blockages.
www.mc-techgroup.com PSS-20 | 1.00.01 23