Perma Pure Micro-GASS UG - Manual (Page 9)

9 Micro-GASS User Manual
4. Start-Up/Shutdown Procedures
4.1 Start-Up
Once all sample, purge, and electrical connections have been made, the system is ready for
operation. Start with the sample flowmeter closed and system and pump power switches in the
“OFF” position.
1. Turn “System Power” switch to the “ON” position. This supplies power to the heated line,
the filter, dryer heaters, and the temperature controller. Allow 10-15 seconds for the
system to start-up. The temperature controller will display the dryer temperature.
2. Adjust dryer set-point temperature to 35°C, or 10°C above the maximum anticipated
dewpoint temperature, whichever is higher. Refer to section 2.5 and Appendix C for the
temperature controller instructions.
3. Switch “Pump Power” switch to the “ON” position. To prevent wet sample gas from entering
the unheated dryer, the sample pump is powered via the temperature controller. A relay in
the temperature controller remains open until the system reaches 40°C. The system
requires 10-15 minutes before the operating temperature is reached; and the pump then
becomes energized. There will be a temperature spike associated with the start of sample
flow. This is acceptable provided the temperature stabilizes within a few minutes.
4. Open the flow meter, adjust the flow to the desired rate (0.5 to 1 lpm). Lower flows result in
dryer gas samples. Samples with a dewpoint of greater than 35°C should be run at no
more than 0.5 lpm.
4.2 Shutdown:
Do not permit wet gases to condense in the Nafion dryer. Follow this
procedure to purge wet sample gas from the system before shutting down:
1. With system and pump power switches in the “ON” position remove the filter
cap from the bottom of the enclosure (Check condition of the filter element.)
2. Allow the pump to run for at least two minutes.
3. Turn the power switches to the “OFF” position and replace the filter cap.
b. Purge Connections
1/4” Bulkhead compression fittings located on the side of the enclosure are for the purge
connections. Connect the “Dry Sample Outlet” port on the Micro-GASS enclosure to the inlet port
of the sensor. Connect the sensor exhaust/outlet back to the “Dry Sample Return” on the
Micro-GASS. No heated line is required for these connections unless the lines will be exposed to
cool temperatures (<10°C).
c. Sample Exhaust
The sample exhaust can either vent freely, or can be piped away from the Micro-GASS . This gas
is “wet” and condensation in the line is likely.
d. Calibration Gas Connection
1/4” Bulkhead compression fitting is located on the enclosure bottom. The port must be plugged
when not in use. A cap for this purpose is provided.