Teledyne GFC-7000T - Trace CO2 Analyzer - manual - Manual (Page 251)

Troubleshooting Model GFC7000TA Carbon Dioxide Analyzer
Teledyne Analytical Instruments 233
 Place a finger over an Exhaust outlet on the rear panel of the instrument.
 If gas is flowing through the analyzer, you will feel pulses of air being expelled from the
Exhaust outlet.
4. If gas flows through the instrument when it is disconnected from its sources of zero air, span gas
or sample gas, the flow problem is most likely not internal to the analyzer. Check to make sure
that:
 All calibrators/generators are turned on and working correctly.
 Gas bottles are not empty or low.
 Valves, regulators and gas lines are not clogged or dirty.
10.2.2.2. Low Flow
1. Check if the pump diaphragm is in good condition. If not, rebuild the pump (See Section 9.3.2).
Check the Spare Parts List for information of pump rebuild kits.
2. Check for leaks as described in Section 9.3.3. Repair the leaking fitting, line or valve and re-
check.
3. Check for the sample filter and the orifice filter for dirt. Replace filters (See Sections 9.3.1 and
11.5.1 respectively).
4. Check for partially plugged pneumatic lines, orifices, or valves. Clean or replace them.
5. If an IZS option is installed in the instrument, press CALZ and CALS. If the flow increases then
suspect a bad sample/cal valve.
10.2.2.3. High Flow
The most common cause of high flow is a leak in the sample flow control assembly or between there and
the pump. If no leaks or loose connections are found in the fittings or the gas line between the orifice and
the pump, rebuild/clean the sample flow control assembly as described in Section 11.6.1.
10.2.2.4. Displayed Flow = “XXXX”
This warning means that there is inadequate gas flow. There are four conditions that might cause this:
1. A leak upstream or downstream of the flow sensor
2. A flow obstruction upstream or downstream of the flow sensor
3. Bad Flow Sensor Board
4. Bad pump
To determine which case it is, view the sample pressure and sample flow functions via the front panel. If
the sample pressure is reading abnormally low, then the cause is likely a flow obstruction upstream of the
flow sensor. First, check the sample filter and make sure it is not plugged and then systematically check
all the other components upstream of the orifice to ensure that they are not obstructed.