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007-08-001 Issue C
Page 3
Operation of the Pneumatic Test Kit
4. Set the back pressure bypass valve to the up position, and adjust the back pressure reading on the back
pressure gauge, to the required value for the flow rate.
5. Note the reading on the flow meter. The flow reading with back pressure applied should generally be within
5% of the reading with no back pressure - refer to the sample pump compensation specification.
6. Set the back pressure bypass valve to the bypass (down) position. Repeat this process at other flow rates
if required.
7. At low flow rates and zero back pressure the flow pulsation created by the sample pump can make it
difficult to take an accurate flow reading. This can be resolved by using the back pressure adjuster valve
to apply a small back pressure of 2 - 4 inches H
2
O, setting the required flow rate, then increasing the back
pressure to the required level.
Sample Media Back Pressure Check
1. Connect the inlet hosetail of the pump to the pump connection hosetail on the pneumatic test kit using a
length of flexible tubing.
2. Place the sample media into the sample head and connect the sample head outlet to the air inlet connection
hosetail on the pneumatic test kit.
3. Ensure that the back pressure bypass valve is in the bypass (down) position.
4. Turn on the sample pump and set the desired flow rate as detailed in the pump instruction manual. Note
the reading on the pneumatic test kit flow meter.
5. Note the reading on the back pressure gauge. A high sample media back pressure compared with the
pump performance specification, could indicate potential problems during a sample run, such as reduced
run times and the potential for flow faults. Either use a higher specification pump or a less restrictive
sample media for the application.