generator fuel quality assurance

Emergency Back-Up Generator
Fuel Quality Assurance Guide

How to check the quality of your fuel

The fuel in your generator is the single most overlooked item in maintaining a back up generator to ensure it runs. Don’t let a decade old tank of diesel be your weak link. Be prepared and know your back up generator fuel quality is ready with these best practices.

Back up generators are everywhere when you start looking for them. Rarely needed, but when a storm or disaster strikes their failure to fire will be extremely conspicuous. In the Pacific Northwest where resilience planning around a major subduction zone earthquake is a monthly subject of talk, back up diesel will be the only immediately power source after a quake. For that reason, diesel generators are taking center stage for emergency preparedness, placing those who maintain them in some high level policy discussions.

Avoid a double emergency when the back up power isn’t there for your need by focusing on the diesel fuel quality.

The worst-case scenario for fuel quality is water getting into your diesel fuel reservoir as well as biological growth occurring in that water logged diesel. If water is present in diesel, and that diesel is in a warm dark place, bacteria will start growing in your tank. So first preventive step is watch for water. The most likely problem with fuel you will see is the fuel aging and degrading in place over years of not being used. That can be addressed with your routine maintenance on the tank.

Note: To get a small amount of water or to ensure a dryer tank of fuel, CIM TEK makes a Tank Dryer which absorbs a small amount of water in a tank. Handy similar to adding a desiccant into a closet with a slight condensation issue.

Sampling and Onsite Testing of Generator Diesel Tank Fuel Guide

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Getting started on back up generator fuel quality.

First, ensure you are testing the generator by running it once a month.  Run the generator for a while to use up fuel and be prepared to order a regular top off when you get below 3/4th of a tank. When checking the fluids on the generator prior to start up see if the fuel filter has a visual transparent bottom where you can see what the fuel looks like there. If it looks like dirty fuel take notice.  After cycling the generator take a peek and make sure the fuel it’s pulling into the generator is bright (not dark and degraded).  If you are seeing any water (even a small drop) that is an indication of real concerns.

If you are using up half a tank a year and adding to it, the fuel quality will usually stay within specification.  If you have worries the easiest way is to just start over. With older generators sometimes it’s a good idea to just evacuate the tank (empty all the older diesel fuel) and replace it with fresh diesel treated and stabilized for long term storage.

Most back up generators are seeing routine annual maintenance where the mechanical needs of the equipment are walked through. If this is occurring ask for a bottom sample from the back up generators fuel tank. Also ask to see what the fuel in the bottom of the fuel filter (assuming they are changing that) would give an indication if problems might exist deep in the fuel tank.

Do you have questions about diesel fuel storage?

If you have questions about fuel storage, Star Oilco has answers.  We do not clean tanks but will help you figure out if your fuel quality has been compromised and your tank needs to be cleaned.

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