Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 6-1 Maintenance Intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 6-1 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 6-2 Automatic Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 6-2 Manual Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 6-2 Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 6-2 Xi Components Replacement . . . . . . . . . . . . . . . . . . . . . . page 6-3 I/O Board Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . page 6-4 AC Relay Board Replacement . . . . . . . . . . . . . . . . . . . . . . page 6-8 Power Supply Board Replacement . . . . . . . . . . . . . . . . . . page 6-11 Xi Front Panel Replacement . . . . . . . . . . . . . . . . . . . . . . . page 6-12 DR Board Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . page 6-14
This section identifies the calibration methods available and provides the procedures to maintain and service the Xi.
Install all protective equipment covers and safety ground leads after equipment repair or service. Failure to install covers and ground leads could result in serious injury or death.
The maintenance interval required is quite variable, depending on the type of service the analyzer is placed into. The zirconium oxide sensing cell is non-depleting, and has no specific shelf life or a defined life in flue gas operation. The cell of a probe that is mounted inside a boiler that is burning natural gas may shift very little over several years. Acidic compounds are the main aggressors to the sensing cell, typically SO2 resulting from sulfur contained in coal and heavy oil fuels, and also HCl from the combustion of plastics in municipal incinerators and in industrial thermal oxidizers. Sensing cells may experience significant degradation and signal shift in this type of service, particularly if the operating levels of O2 are very low (below 1% O2).
A calibration check is generally recommended on a quarterly basis (every 3 months) by flowing bottled gas to the probe. (Make sure that the operations personnel are notified when doing this, and also make sure that the O2 control loop is placed in manual mode). If the probe readings vary significantly from the bottle values, then a formal calibration should be conducted as noted in Section 4: Startup and Operation.
The Xi offers a "calibration recommended" diagnostic that will indicate when the probe needs to be calibrated.
