Teledyne GFC-7000E - Trace CO2 Analyzer - Manual (Page 161)

Model GFC7000E Instruction Manual MAINTENANCE SCHEDULE & PROCEDURES
04584 Rev A1 150
9.3.2. Rebuilding the Sample Pump
The diaphragm in the sample pump periodically wears out and must be replaced. A sample
rebuild kit is available – see Appendix B of this manual for the part number of the pump rebuild
kit. Instructions and diagrams are included with the kit.
Always perform a Flow and Leak Check after rebuilding the Sample Pump.
9.3.3. Performing Leak Checks
Leaks are the most common cause of analyzer malfunction; Section 9.3.3.1 presents a simple leak
check procedure. Section 9.3.3.2 details a more thorough procedure.
9.3.3.1. Vacuum Leak Check and Pump Check
This method is easy and fast. It detects, but does not locate most leaks, it also verifies that the
sample pump is in good condition.
1. Turn the analyzer ON, and allow enough time for flows to stabilize.
2. Cap the sample inlet port.
3. After several minutes, when the pressures have stabilized, note the following. In the TEST
menu, note the SAMPLE PRESSURE reading.
4. If the reading is < 10 in-Hg, the pump is in good condition and there are no large leaks.
5. If both readings are equal within 10%, the instrument is free of large leaks.
9.3.3.2. Pressure Leak Check
If you can’t locate the leak by the above procedure, use the following procedure. Obtain a leak
checker similar to the Teledyne Instruments part number 01960, which contains a small pump,
shut-off valve, and pressure gauge. Alternatively, a convenient source of low-pressure gas is a
tank of span gas, with the two-stage regulator adjusted to less than 15 psi with a shutoff valve
and pressure gauge.
CAUTION
Do not use bubble solution with vacuum applied to the analyzer. The
solution may contaminate the instrument. Do not exceed 15 PSIG
pressure.
1. Turn OFF power to the instrument.
2. Install a leak checker or tank of gas as described above on the sample inlet at the rear panel.
3. Remove the instrument cover and locate the inlet side of the sample pump. Remove the flow
assembly from the pump and plug it with the appropriate gas-tight fitting.