- 785 Westney Road South, Unit #4, Ajax, Ontario L1S 7G1
- info@genworx.ca
All makes serviced · Ontario-wide · Based in Ajax
Diesel in a vehicle is stable, because it gets used within weeks. Diesel in a standby tank might sit for three years.
Most people assume diesel is stable. Put it in a tank, leave it, and it will be there when you need it. Over two or three years in a standby tank, it changes considerably.
Tanks breathe. As the temperature rises and falls through the day and through the seasons, air moves in and out of the vent. That air carries moisture, and when it cools inside the tank the moisture condenses on the walls and runs down. Water is heavier than diesel, so it settles at the bottom — the same place the fuel pickup draws from.
Where water sits beneath diesel, there is a boundary layer that is an ideal environment for bacteria and fungus. They feed on the fuel and produce a dark slime, widely known in the trade as diesel bug. It blocks filters, it corrodes the tank, and once established it is difficult to get rid of without treating the tank properly.
Diesel reacts slowly with oxygen and forms heavy, sticky compounds that drop out of the fuel as sludge. Modern low-sulphur diesel and biodiesel blends are more prone to this than the fuel of twenty years ago — biodiesel in particular attracts water and degrades faster.
Water plus a steel tank equals rust, and the rust ends up in the fuel as particles that go straight to your filters.
This is what catches people out. Contaminated fuel usually does not stop a generator starting. A monthly exercise run draws a small amount of fuel, gently, from the clean part of the tank. Everything looks normal.
A real outage is different. The engine runs for hours at full load, consuming fuel far faster, and it agitates the tank. Sludge and water that have been sitting quietly at the bottom get stirred up and pulled into the fuel system. Filters block, fuel pressure drops, and the engine shuts down — often an hour or two into exactly the emergency the generator exists for.
The monthly test run is drawing from the top of the tank. The outage draws from the bottom.
A sample sent for laboratory analysis shows water content, microbial growth, particulate contamination and general condition. It is inexpensive and it takes the guesswork out.
Fuel polishing circulates the entire tank contents through filtration and water separation on site. It removes the water, the sludge and the biological matter and cleans the tank — without disposing of thousands of litres of fuel or taking the generator out of service.
Check tank seals and vents, drain water separators on schedule, and keep the tank reasonably full so there is less air space for condensation to form in.
Biocide deals with microbial growth. Stabiliser slows oxidation. Both are worth using where fuel turns over very slowly — but treatment is not a substitute for cleaning a tank that is already contaminated.
Fuel is one of the most common reasons standby generators fail during real outages, and it is one of the easiest problems to prevent.
Test annually. Polish when the results say to. Keep the water out.
GenWorx provides fuel testing and diesel fuel polishing for standby generators across Ontario.
Weekly, monthly, semi-annual and annual — and who is responsible.
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