In operation, air ejectors require little atten-tion. However, the following points should be noted.

1. The steam pressure at the nozzle inlet must not be less than that for which the ejector is designed (stamped on the nameplate). Pressures at the air ejector nozzle may be 10 to 15 psig higher than the minimum specified by the manufacturer.

2. The primary causes of air ejector trouble are low steam pressure, wet steam, obstructed nozzle, or a clogged steam strainer. Such trouble is indicated by failure to obtain or to maintain the required vacuum. If the trouble is due to low steam pressure or to wet steam, it will be necessary either to increase the steam pressure or to pro-vide suitable drainage by installing a trap or by using manual means. If the nozzle or steam strainer is clogged, it must be removed and cleaned. Most plants are provided with two sets of air ejectors; this permits the use of the plant on one unit while the second is being cleaned or repaired. However, some of the latest plants have only one set of air ejectors.

When it becomes necessary to clean air ejec-tor nozzles, they should be cleaned with the special nozzle reamers furnished to each ship for this pur-pose. Sharp-edged tools should never be used for cleaning nozzles because the nozzle surfaces will be damaged and the efficiency of the air ejectors will be impaired.

Procedures for testing air ejectors can be found in the manufacturers technical manual. In general, the same maintenance procedures should be followed for distilling plant air ejectors as for air ejectors for main condensers.

Since the air ejector strainer is usually an integral part of the air ejector inlet, it should be inspected and cleaned in accordance with the PMS. When a new plant is first put into opera-tion, the strainer may require cleaning once a day or even more frequently. Failure to keep the strainer clean will cause a reduced or fluctuating vacuum. When a strainer or a nozzle becomes damaged, it should always be replaced with a new one.