While the average life expectancy of a well-maintained service vehicle is approximately 5000 hours (assuming 300,000 miles at 60 mph), a typical standby generator set can last from 10,000 to 30,000 hours. On the other hand, a standby generator might operate as little as 26 hours a year (based on only 30 minutes of weekly exercise and no outages) or as much as several hundred hours a year, depending upon the number and duration of power outages.
In either case, a standby generator set could conceivably last 20 to 30 years. One way to ensure a long, reliable operating life is to implement a preventive maintenance (PM) program.
Preventive maintenance and service are typically done on a schedule based upon engine hours and/or time periods. The maintenance cycle can—and should—be adapted to meet specific application needs. The more hours per year a unit operates, the more frequently it will require service. Environment also plays a role: The more severe the environment (dusty, extremely hot or cold, highly humid, etc.), the more frequent the need for service may be.
Most OEM-recommended maintenance schedules for generators—whether a unit is powered by diesel or gaseous fuels—are roughly the same. The typical maintenance cycle includes a general inspection followed by scheduled inspection and service of the following critical systems:
At a minimum, a good visual inspection should be done on a monthly basis, as well as after any extended generator run times. Here are some basic tips: The general inspection
In addition to monthly inspections, check the coolant thermal-protection level every six months. Use the appropriate tester for the type of coolant being used. At the same time, inspect the accessory drive belts for correct tension and condition.
Annual maintenance begins with changing the engine oil and filter. If you want to extend oil-change intervals, consider an oil-analysis program. This will give you recommendations based on the actual condition of the lubricating oil.
Replace the air filter and fuel filters, as well. If it is a diesel unit that does not use a lot of the fuel in its storage tank, consider having the fuel in the tank filtered and checked for additive content.
Two often-overlooked items that require annual inspection—and possible maintenance—are the alternator itself and the transfer switch:
Other generator PM aspects
The above items are by no means a complete list. Other PM aspects worth considering include the conducting of weekly exercise periods under load to test the entire system for proper operation and make the generator work at operating temperature. A monthly load test of at least 30% of rated load is required in some applications, using the building load, a load bank or a combination of the two.
OEMs provide detailed maintenance guidelines that should be followed to provide the longest most reliable service life possible for their respective equipment. General guidelines for specific applications also can be found in several recognized standards. One such standard is the NFPA 110, Standard for Emergency and Standby Power Systems (2010 Edition). It is an excellent resource on general-maintenance requirements and detailed information on some specific maintenance items. This standard also contains a suggested maintenance schedule which, if followed, will meet minimum maintenance requirements for Level 1 and Level 2 emergency standby power systems. In the meantime, for a handy checklist, refer to the sidebar on page 43. Remember: Establishing and following a thorough maintenance and service plan will provide you with a reliable power supply for many years. MT
Here’s a handy checklist to help guide you as you work to maintain your standby generator(s). Be sure to take note of the frequency recommendations for these maintenance activities.
Bi-Annual Maintenance (Schedule maintenance with a certified technician.)
Annual Maintenance (Schedule maintenance with a certified technician.)