A backup generator is built for the day everything else fails. But it is only as reliable as the parts nobody thinks about until it is too late. The filters are among them.
Six filter families, six systems
Hifi Filter divides the filters on a generator into six families. Each family protects its own critical system:
- Air filter keeps dust and particles out of the engine intake. A clogged air filter means poorer combustion and less power.
- Breather filter cleans oil mist from the crankcase gases, so it does not end up in the surroundings or in the intake.
- Fuel filter removes dirt and water from the diesel before it reaches the injection system. This is where problems from the tank show up first.
- Oil filter captures wear particles and dirt in the lubricating oil and protects bearings and pistons.
- Coolant filter keeps the cooling system clean, so the engine does not overheat during long running periods.
- Urea filter protects the urea (AdBlue) dosing on engines with an SCR catalyst, so the exhaust aftertreatment works.
A filter change is cheap insurance
Backup generators often run only during the annual test. That does not mean the filters can be left for years. Diesel ages, oil breaks down and moisture gets in, even when the engine is standing still.
Hifi Filter puts it simply: regular filter changes are one of the simplest ways to secure uptime. It costs far less than a generator that stops after an hour because the fuel filter is blocked.
The tank and the engine are connected
We have previously written about how the diesel in the backup power tank should be kept clean with preventive fuel polishing. The filters on the engine are the next link in the same chain. A clean tank and fresh filters together are what make the generator start and keep running.
Who should think about this?
- Hospitals, care homes and data centres with backup power that must not fail.
- Supermarkets, cold stores and food producers, where refrigeration depends on the generator.
- Waterworks, district heating plants and public buildings with emergency preparedness requirements.
- Ships and ports, where generators are also part of daily operations.
Hifi Filter at Arne Nielsen A/S
Arne Nielsen A/S is an official Hifi Filter dealer. Write to us at info@arnenielsen.com with the generator make and engine type or the filters’ original part numbers, and we will find the right filters and get back to you with a quote.
Source: Hifi Filter on LinkedIn, 6 October 2026.