General Monitors 2180A - Maintenance; General Maintenance; Periodic System Verification

Model 2180A
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4.0 Maintenance
4.1 General Maintenance
Once installed, the Model 2180A Controller requires little or no routine maintenance,
other than periodic calibration checks. General Monitors recommends that a calibration
schedule be established and adhered to. GMI also recommends that a logbook be kept,
showing calibration dates and dates of sensor replacement.
Considering the toxicity of hydrogen sulfide, General Monitors strongly recommends the
period between calibrations should never exceed 90 days.
It is important that the owner/operator of this equipment determine the correct calibration
schedule for their particular environment. Environmental conditions and contaminants
can cause the frequency of calibration to be substantially shorter than 90 days. This is
the only method of ensuring proper system operation and response to hydrogen sulfide.
More frequent calibration checks are encouraged to detect problems, such as mud
collecting on the sensor heads; accidental painting over of sensors, etc. A calibration
check is defined as the procedure of applying a known concentration of gas to the system
sensors, while observing the controller. The visual display will indicate the gas
concentration, and alarm indicators/circuits will activate in direct relationship to gas
concentration. Calibration adjustments must be made if results vary (please refer to
Section 3.7).
4.2 Periodic System Verification
The following system verifications should be performed annually. Verify wiring, terminal
connections and stability of mounting for all integral safety equipment including, but not
limited to:
• Power supplies
• Control modules
• Field detection devices
• Signaling / output devices
• Accessories connected to field and signaling devices
Proper system operation should be verified by performing a full, functional test of all
component devices of the safety system, ensuring that the proper levels of alarming
occur.
Fault/Malfunction circuit operation should be verified.
Calibration intervals should be independently established through a documented
procedure, including a calibration log maintained by plant personnel or third party testing
services.