4.0 MAINTENANCE SCHEDULE
The maintenance requirements of the M201E are the same as a standard M200E NOx analyzer but with additional maintenance items (Table
The M201E requires the following additional maintenance items.
Table 4-1. Preventative Maintenance Schedule
Item | Maintenance Interval | Reference Section |
NO2 molybdenum converter |
| Section 8.2.3 M200E Manual |
|
| |
| Test Every Three Months |
|
M501 NH3 Converter |
| Section 4.1of this manual. |
|
| |
Reaction Cell | Clean annually or as necessary | Section 9.3.9 M200E Manual |
AutoZero flow check | Quarterly as needed | Section 4.4 of this manual. |
4.1M501 NH3 MAINTENANCE
The M501 NH3 external converter is operated at 825 ºCelsius. Because of this the stainless steel ¼” tube internal to the converter slowly oxidizes and may require replacement. Over time the converter’s efficiency will degrade, due to aging of the internal catalyst. This is characterized by a CONV value on the TNx channel of < 0.8 or > 1.2, despite the converter being at temperature. The efficiency of the converter should be checked quarterly. The converter should be cleaned out on a yearly basis by removing the outer tube and shaking the fine dust particles from both the outer and inner tubes. This is also a good time to replace the catalyst screen, if necessary.
The following procedure describes how to disassemble and replace converter parts. The various parts in the converter become delicate and brittle after prolonged exposure to high temperatures. It is therefore a good idea to have a complete set of replacement parts on hand before starting, as listed in Table
05206H DCN5910 | 35 |