Teledyne GFC 7001E Performing Leak Checks, Vacuum Leak Check and Pump Check, Pressure Leak Check

Maintenance Model GFC7001E Carbon Dioxide Analyzer

12.3.3.PERFORMING LEAK CHECKS

Leaks are the most common cause of analyzer malfunction; Section 12.3.3.1 presents a simple leak check procedure. Section 12.3.3.2 details a more thorough procedure.

12.3.3.1.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 pressure has stabilized, scroll through 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.Check the sample gas flow. If the flow is <10 cm3/min and stable, there are no large leaks in the instrument’s pneumatics.

12.3.3.2.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 P/N 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

GENERAL SAFETY HAZARD

Do not use bubble solution with vacuum applied to the analyzer. The solution may

contaminate the instrument. Do not exceed 15 PSIG pressure.

6.Turn OFF power to the instrument.

7.Install a leak checker or tank of gas as described above on the sample inlet at the rear panel.

8.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.

9.Pressurize the instrument with the leak checker, allowing enough time to fully pressurize the instrument through the critical flow orifice. Check each fitting with soap bubble solution, looking for bubbles. Once the fittings have been wetted with soap solution, do not re-apply vacuum, as it will suck soap solution into the instrument and contaminate it. Do not exceed 15 psi pressure.

10.If the instrument has one of the zero and span valve options, the normally closed ports on each valve should also be separately checked. Connect the leak checker to the normally closed ports and check with soap bubble solution.

11.Once the leak has been located and repaired, the leak-down rate should be < 1 in-Hg (0.4 psi) in 5 minutes after the pressure is shut off.

Teledyne Analytical Instruments 265