Teledyne 326, 327 and 328 - Oxygen analyzers - Manual (Page 37)

Teledyne Analytical Instruments
Maintenance Maintenance Maintenance Maintenance Maintenance Model 326/327/328 Model 326/327/328 Model 326/327/328 Model 326/327/328 Model 326/327/328
5-3
c. Check calibration gasses: zero, span, and sample are appropriate
types or formulations for the instrument and cell type.
d. Instrument has had time to stabilize.
e. Ambient and sample-gas temperatures are in allowable range for the
instrument.
5.2.2 Electronics Checks 5.2.2 Electronics Checks 5.2.2 Electronics Checks 5.2.2 Electronics Checks 5.2.2 Electronics Checks
If the following checks do not give the expected results, problem is
probably in the electronics.
a. Remove Cell: Output should go to zero.
b. Short cell contacts together: Output should go full scale or higher, or
it should go below zero.
5.2.3 Gas Checks 5.2.3 Gas Checks 5.2.3 Gas Checks 5.2.3 Gas Checks 5.2.3 Gas Checks
a. Instrument spans OK, but doesn't go to zero with zero gas.
(1) There may be a gas leak: Vary the flow rate. If the detected
oxygen level varies with flow rate, there is a leak (Leaks can be
caused by lose fittings or damaged tubing, or by diffusion
through walls of tubing or other parts of the sampling system. A
diffusion leak is normally so small that it can be detected only by
trace oxygen instruments.)
(2) The zero gas may be contaminated. This in turn can be caused
by improper regulator attachment procedures.
b. Instrument zeros OK, but won't span high enough.
(1) Exhausted or damaged cell. Replace cell. (Cell damage can be
caused by puncturing membrane when removing shorting clip or
from storing the cell at too high a temperature.)
(2) Incorrect cell for application. Check Specific Cell Information .