Final Checklist Before Buying A Used Diesel Generator

When buying a used diesel generator, just like buying a used car, you need to

be confident that you’re not going to finish up with an expensive problem.

You should see evidence of the number of hours it has run and ideally that the generator has been serviced according to the manufacturer’s recommendations. But, just like a used car, can you be sure that the running hours stated on the control panel are genuine, that the service records are accurate and that the important filters and lubricants are correct? Not always! Sometimes it is just not possible to obtain the right information and that is why the buyer should be mindful of who the seller is.

Once you are confident that you can trust the information, buying a used generator can be a very efficient way of reducing capital outlay if your application is for standby power.

Every Used generator set should be tested and follow a staged process prior to sale:

Selection

The first step in ensuring reconditioned generators will meet expectation is to select good quality equipment. That will mean shopping around and doing your research. It is prudent to review an engine’s history and maintenance regime before purchase or acceptance in whole or in part exchange. Used generators that are nicely painted, have a new control panel fitted or look newer than the hours recorded (or stated by the seller) should ring alarm bells – be careful, they might have been used and abused.

Initial Load Test

Using a calibrated load bank to test the capability of the engine and complete unit under duress is a very good way of uncovering any failings. A load test is not unlike taking a used car and driving it hard on a motorway for an hour. A full load test up to 100% of capacity is recommended. It will help diagnose any potential shortfalls and should help you make an informed choice.

Repairs & Upgrade

You should always request a new control panel as part of the purchase deal as analogue units are not compatible with many modern telecommunication devices that could be fitted and be useful at a later date. The control and alarm system may include an auto start with automatic mains failure capability, remote start, modems, GSM’s and acoustic enclosures could be upgraded or retro-fitted. Consumables such as filters, belts and hoses should be checked for ware and be replaced if appropriate.

Final Load Test

If a used diesel generator has failed the initial load test it may require another if the faults uncovered were considered to be minor and the purchase still worth pursuing. The unit should be tested again on load for a minimum of one hour and with staged loads up to 100%. During test both the engine and alternator should be monitored for speed and voltage characteristics to ensure the pre-requisite demands are met. A test certificate should be produced.

A good source for Used Diesel Generators, particularly large generators, would be hospitals, universities, telecommunication centres, banks and data centres. More often than not large generators installed for backup power in the UK are rarely, if ever, called into action and so typically have very low hours and are in good condition.