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Instruction / / 4.1 Factory Calibration The module has been factory calibrated to alarm as indicated in Table 4.1 or as marked on the calibra- tion tag shipped with the module. 4.2 Frequency of Calibration The manufacturer recommends that the calibration of each gas sensor module be verified monthly dur- ing the first three months of operation and then quar- terly. More frequent checks are necessary during periods of extreme humidity and temperature changes. The monitor should have operated con- tinuously (uninterrupted) for at least 24 hours prior to calibration adjustment. 4.3 Calibration Process The output signal of the gas sensor module is cali- brated using a calibration gas mixture containing a known concentration of the gas of interest and a balance of air. The concentration of the span gas must be within the full scale of the sensor module and must be equal to the alarm point desired. Calibration requires application of the span gas to the sensor and adjustment of the sensitivity adjust- ment potentiometer. Warning: During calibration the alarm will turn on and remote alarms connected to the alarm relays will be activated. Disable the remote alarm if neces- sary. 4.4 Equipment Required The following tools and equipment will be required for calibration: - Jewelers Screwdriver - Calibration Gas - Calibration gas delivery system For accurate calibration use a gas mixture at the required concentration mixed in an air balance, rather than with an inert gas like nitrogen. This gas and the required delivery equipment such as the Model 1200-26 Calibrator is available from Sierra Monitor Corporation. 4.5 Calibration Procedure 1. The monitor should be in the safe condition prior to calibration (green LED "ON"). Be sure that the area is non -hazardous before proceeding. Disable alarm devices 2. On the 20X, remove the cover prior to expos- ing the sensor with gas. On the 200X series (see Figure 1.1 or 1.2) the sensor is in the lower right hand corner of the electronics board and the cover does not need to be removed. 3. Apply calibration gas directly to the sensor. 4. If the monitor alarms (red LED "ON") within one minute and stops within one minute of the re- moval of the calibration gas, the monitor is in calibration and requires no adjustment. 5. If the monitor fails to alarm within one minute of the application of the gas, use a jeweler's screwdriver to adjust the sensitivity adjustment potentiometer (R4, Fig. 4.1) clockwise until the alarm turns "ON". 6. If the monitor fails to stop alarming within one minute of removal of the gas, adjust the poten- tiometer counterclockwise until the alarm stops. 7. After adjustment, repeat the application and re- moval of gas to verify calibration. 8. When the calibration is complete, reconnect any alarm equipment as necessary. Page: 5 20X/200X Gas Sensor Modules (08/04) Calibration Model Time Gas cc/min 201/2001 203/2003 206/2006 30 sec. 1000 ppm CH4 1 min. 50 ppm H2S 1 min. 100 ppm CO 50 50 50 Table 4.1 4.2 Frequency of Calibration The manufacturer recommends that the calibration of each gas sensor module be verified monthly dur- ing the first three months of operation and then quar- terly. More frequent checks are necessary during periods of extreme humidity and temperature changes. The monitor should have operated con- tinuously (uninterrupted) for at least 24 hours prior to calibration adjustment. 4.3 Calibration Process The output signal of the gas sensor module is cali- brated using a calibration gas mixture containing a known concentration of the gas of interest and a balance of air. The concentration of the span gas must be within the full scale of the sensor module and must be equal to the alarm point desired. Calibration requires application of the span gas to the sensor and adjustment of the sensitivity adjust- ment potentiometer. Warning: During calibration the alarm will turn on and remote alarms connected to the alarm relays will be activated. Disable the remote alarm if neces- sary. 4.4 Equipment Required The following tools and equipment will be required for calibration: - Jewelers Screwdriver - Calibration Gas - Calibration gas delivery system For accurate calibration use a gas mixture at the required concentration mixed in an air balance, rather than with an inert gas like nitrogen. This gas and the required delivery equipment such as the Model 1200-26 Calibrator is available from Sierra Monitor Corporation. 4.5 Calibration Procedure 1. The monitor should be in the safe condition prior to calibration (green LED "ON"). Be sure that the area is non -hazardous before proceeding. Disable alarm devices 2. On the 20X, remove the cover prior to expos- ing the sensor with gas. On the 200X series (see Figure 1.1 or 1.2) the sensor is in the lower right hand corner of the electronics board and the cover does not need to be removed. 3. Apply calibration gas directly to the sensor. 4. If the monitor alarms (red LED "ON") within one minute and stops within one minute of the re- moval of the calibration gas, the monitor is in calibration and requires no adjustment. 5. If the monitor fails to alarm within one minute of the application of the gas, use a jeweler's screwdriver to adjust the sensitivity adjustment potentiometer (R4, Fig. 4.1) clockwise until the alarm turns "ON". 6. If the monitor fails to stop alarming within one minute of removal of the gas, adjust the poten- tiometer counterclockwise until the alarm stops. 7. After adjustment, repeat the application and re- moval of gas to verify calibration. 8. When the calibration is complete, reconnect any alarm equipment as necessary. Page: 5 20X/200X Gas Sensor Modules (08/04)