Buying a used diesel generator

Begin with your application

Before comparing prices, make a list of the equipment you intend to power and how it will operate. Record the running loads, large motors, starting methods and any loads that must operate at the same time. Describe whether the generator will support daily operation or provide emergency backup. Give this information to the supplier when asking for a suitable used generator.

Compare the individual machine

Used generators are individual assets. A familiar engine brand and low recorded hours do not tell the whole story. Ask for clear photographs of the complete set and its identification plates, then check the year, operating hours, enclosure, engine model and alternator model against the quotation.

• Review available maintenance and service records.
• Ask how the recorded hours have been established.
• Agree the inspection, servicing and testing included in the price.
• Check the condition of the cooling system, hoses, wiring and enclosure through a suitable inspection.
• Confirm the installed controls, circuit breaker and any accessories needed for your application.

Understand the quoted output

Confirm which output is prime and which is standby. Check voltage, frequency, phase and power factor, and account for site conditions. The advertised kVA is a useful starting point for searching; it is not a substitute for confirming that the specific set can supply your load.

Look at the complete purchase cost

Ask whether the quotation includes preparation, testing, transport, commissioning or other work. Confirm any warranty in writing. Delivery planning should cover the generator dimensions and weight, route access and who is responsible for unloading. For an export purchase, ask for the shipping scope and destination charges to be clearly identified.

Keep a clear written record

Before paying, check the exact unit reference, agreed specification, included equipment, payment terms and delivery arrangements. Retain the quotation and agreed testing records. If a particular feature is essential, make sure it appears in the order documentation.