Service
Generator Repair
Diagnosis and repair of diesel and petrol generating sets across Nairobi, from a set that cranks but will not start to one that runs but produces no usable output.
Symptoms we see
- Cranks but will not start
- Starts then shuts down after a few seconds
- Runs but there is no output at the board
- Output voltage too high, too low, or hunting
- Overheating or shutting down on high temperature
- Black smoke under load
- Will not take load, or trips when a motor starts
- Battery flat every time it is needed
What's included
- Fault diagnosis before any part is quoted
- Insulation and winding tests on the alternator
- AVR test and replacement where it is genuinely the fault
- Fuel system checks: filters, lift pump, injectors, air in the line
- Cooling system: radiator, thermostat, water pump, fan belt
- Starting system: battery, starter, charging alternator, control fuses
- Controller and changeover checks, including ATS behaviour
- A written report saying what was wrong and what was done
Diagnosis first, parts second
The most expensive way to repair a generator is to replace parts in order of suspicion. An alternator is one of the two costliest components on the set and an automatic voltage regulator is one of the cheapest, and the symptom that points at both is identical: the engine runs and nothing comes out.
So the sequence matters. We test the AVR and the excitation circuit, then the windings, then the breaker and changeover, and we quote the part that failed rather than the part that would be convenient to sell.
The faults we actually see in Nairobi
Fuel contamination and stale diesel. A standby set that runs for ten minutes a month spends the rest of its life with the same diesel in the tank. Water settles, bugs grow in it, and the filter blocks. On the day of a real outage the set runs for two minutes and dies. This is the single most common call we get, and it is a maintenance failure rather than a mechanical one.
Flat batteries. A generator’s battery is the only component whose failure guarantees the whole set is useless. It sits unused, self-discharging, with a charger that may or may not be working, and nobody notices until the day it is needed.
AVR failure. Voltage that hunts, sits high enough to damage equipment, or collapses under load. Kenyan supply conditions and the surges that come with restoration after an outage are hard on regulators.
Undersizing discovered late. A set that trips whenever a borehole pump or a compressor starts was very often never big enough for that starting load. That is a sizing problem presenting as a fault, and no amount of repair fixes it. We would rather say so than keep charging to investigate.
Cooling. A radiator packed with dust, a failed thermostat, or a plant room with no airflow. A set in an enclosed space recirculates its own hot air and shuts down on temperature while appearing mechanically sound.
What we will tell you honestly
Sometimes a repair is not worth doing. An old set with a worn engine, a failed alternator and no parts availability can cost more to return to service than a replacement of the same rating, particularly in the band below 15 kVA where imported sets are inexpensive. We will say so, with the arithmetic, rather than quote the repair and let you discover it afterwards.
FAQ
▸My generator cranks but will not start. What is it usually?
On a diesel set, most often fuel: a blocked filter, a failed lift pump, or air drawn into the line after running the tank dry. On a petrol set it is more often ignition or stale fuel. We diagnose before quoting because the fix ranges from a filter to an injector pump.
▸The generator runs but nothing comes on. Is the engine the problem?
No. If the engine runs steadily the fault is on the electrical side: the AVR, the alternator windings, the main breaker, or the changeover. An AVR is a fraction of the cost of an alternator, so it is worth testing properly rather than replacing the expensive part first.
▸Do you charge for diagnosis?
Diagnosis is quoted separately from repair so you are never paying for parts nobody has proved you need. If we cannot find the fault you do not pay for a guess.
▸How long do repairs take?
A filter, belt, battery or AVR is usually same-visit if the part is a common size. Alternator rewinds and injector pump work go to a bench and take longer. We tell you which it is before starting.