Model 755A

Instruction Manual

245364-V May 2002

SECTION 6

SERVICE AND MAINTENANCE

WARNING

POSSIBLE EXPLOSION HAZARD

If gases are introduced into this analyzer, the sample containment system must be carefully leak-checked prior to initial start- up, during routine maintenance and any time the integrity of the sample containment system is broken, to ensure the system is in leak-proof condition. Leak-check instructions are provided in Section 2.3.8.

WARNING

ELECTRICAL SHOCK HAZARD

Do not operate without doors and covers secure. Servicing requires access to live parts which can cause death or serious injury. Refer servicing to qualified personnel.

CAUTION

PARTS INTEGRITY

Tampering or unauthorized substitution of components may adversely affect safety of this product. Use only factory documented components for repair.

The information provided in this section will aid in isolation of a malfunction to a particular assembly or circuit. No detailed procedures for component service and maintenance are provided, as they are beyond the scope of this manual. A few detailed checks are included, but only for location of the defective assembly. It is recommended that those familiar with circuit analysis refer to the circuit theory in Section 5 of this manual.

6-1 INITIAL CHECKOUT WITH STANDARD GASES

If instrument readings do not meet specifications, the first step in troubleshooting is to isolate the analyzer from the sample stream and the sample-handling system.

Admit downscale and upscale standard gases to the analyzer. Observe readout on digital display and on recorder (if used).

Digital display reads correctly with standard gases but not with sample gas, the sample and sample-handling systems are suspect. Check these areas.

Digital display reads correctly with standard gases, but the alarm or output devices do not, these devices must be checked individually.

Digital display reads overrange or erratic with standard gases as well as with sample gas, the problem is probably in the detector or the electronic circuitry.

•Overrange - Turn power to analyzer OFF. Tap detector compartment with fingers. Wait 30 seconds, reapply power. If the suspension within the detector assembly is hung up, this procedure may correct the condition. If not, proceed with tests of the detector and electronics.

•Erratic - Problem probably in the detector or the temperature control circuits. Proceed with tests of the detector and electronics. Verification that all circuits are operating properly should be performed before replacing detector.

Rosemount Analytical Inc. A Division of Emerson Process Management

Service and Maintenance

6-1