Chapter 2 Boiler Maintenance

CHAPTER 2 BOILER MAINTENANCE Learning Objective: Recognize maintenance requirements and procedures for boilers and auxiliary equipment; recognize boiler operation steps and checks and safety requirements. As a Utilitiesman, it is your responsibility to operate, maintain, and repair boilers. You can perform operator maintenance on shore-based boilers; perform preventive maintenance and minor repairs on boilers and associated equipment; complete chemical tests on boiler water and feedwater; replace defective boiler tubes; test, adjust, and recalibrate boiler gauges and other accessories. This chapter provides information on some of the methods, procedures, and techniques used to operate, maintain, and repair boilers and associated equipment safely under typical conditions. Because of the broad scope of tasks involved in operating and servicing boilers, this chapter does not tell you all you need to know about the subject. Learning how to accomplish the procedures given in the following sections can help you acquire a basis on which to develop more advanced skills. While the procedures given in this chapter are typical, you should always follow the manufacturer’s instructions for the equipment. MAINTENANCE OF AUXILIARY EQUIPMENT Learning Objective: Recognize and auxiliary equipment maintenance. understand basic A well-planned maintenance program is the key to avoid unnecessary downtime or costly repairs, promotes safety, and aids local inspection. An inspection schedule listing the procedures should be established. It is recommended that a boiler room log or record be maintained for recording the daily, weekly, monthly, and yearly maintenance activities. This provides a valuable guide and aids in the operational efficiency, length of service, and safe operation of a boiler. It is also important to remember that improperly performed maintenance is just as damaging to a boiler as no maintenance at all. MAINTENANCE REQUIREMENTS FOR CONTROL OF WATER LEVEL The need to check water level controls and the water side of the pressure vessel periodically cannot be overemphasized. Most instances of major boiler damage are the result of operating with low water or using untreated (or incorrectly) treated water. Always be sure of the boiler water level and blow down the water column routinely. Check samples of boiler water and condensate according to procedures recom- mended by your water consultant (figs. 2-1 and 2-2). Since the manufacturer generally sets low water cutoff devices, no attempt should be made to alter or adjust these controls. If a low water device should become erratic in operation or if the setting changes from previously established levels, check for reasons and correct it by repair or replacement. Figure 2-3 is a replica of the low water cutoff plate attached to a steam boiler. These instructions should be followed on a definite schedule. These controls normally function for long periods of time and may lead to laxity in testing on the assumption that normal operation will continue indefinitely. On a steam boiler, the head mechanism of the low water cutoff devices should be removed from the bowl at least once a month to check and clean the float ball, the internal moving parts, and the bowl or water column. Remove the pipe plugs from the tees or crosses and make certain the cross-connecting piping is clean and free of obstructions. Controls must be mounted in a plumb position for proper performance. A scheduled blowdown of the water controls on a steam boiler should be maintained. It is impractical to blow down the low water cutoff devices on a hot-water boiler since the entire water content of the system would be involved. Many hot-water systems are fully closed and any loss of water would require makeup and 2-1