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Onsite Generator Repairs

Onsite Generator Repairs · Gauteng

We Repair, Service and Maintain Generators Across Gauteng

Highly recommended, Onsite Generator Repairs comes to homes, businesses and industrial sites across Gauteng to fix faults, carry out services when they are due and run ongoing maintenance plans, on diesel, petrol and gas generators of every make. Call or WhatsApp at any hour: we arrive within 1–2 hours, usually within 1 hour.

Call 076 434 7292WhatsApp usRequest a technician

Or request a technician online

Two technicians at work on portable, home standby and large industrial diesel generators outside a workshop with an Onsite Generator Repairs sign

  • Established 2006

    20 years of experience

  • 24/7 operations

  • We Arrive Within 1–2 Hours

    (usually within 1 hour)

  • Free callouts and quotations

  • One-year warranty

  • Qualified and certified technicians

  • We Service & Repair All Generator Brands

    All generator makes and models

  • 1 kVA–20,000 kVA capability

Core services

Repairs, servicing or maintenance?

A repair fixes a fault. A service is a single visit when the generator is due. Maintenance is an ongoing plan of visits that keeps it ready all year. Pick the one that matches what your generator needs today.

  1. 01 · When something has gone wrong

    Generator Repairs

    Finding and fixing a fault on site when the generator will not start, run, carry the load or make the right power.

    Typical reasons

    • Will not crank, or cranks but will not fire
    • Runs but gives no power, or the voltage or frequency is unstable
    • Overheating, leaks, smoke or a shutdown alarm
    • Trips when load comes on, or the changeover will not transfer

    What it involves

    • Fault finding on the engine, fuel system, alternator, AVR and controls
    • A free quotation before work starts
    • The repair, then a test run under load where possible
    Report a fault

  2. 02 · One visit, when it is due

    Generator Servicing

    A single scheduled visit when the running hours or the date say a service is due: oil, filters, checks and a test run.

    Typical reasons

    • The hour meter has reached the service interval
    • A year has passed on a standby set that seldom runs
    • Load shedding or long outages have brought the hours interval round early
    • The generator has stood unused for months

    What it involves

    • Engine oil changed, with the oil and fuel filters where the engine has them
    • Air filter cleaned or replaced, spark plugs on petrol and gas engines, water drained from a diesel’s separator
    • Coolant, belts, battery and charger checked where fitted
    • A test run and a summary of what was found
    Book a service

  3. 03 · An ongoing plan, all year

    Generator Maintenance

    An ongoing plan of services, inspections and test runs, scheduled around how the generator is used, with a record of every visit.

    Typical reasons

    • Backup power your home, business or site cannot be without
    • Daily running through load shedding, with hours to track between services
    • Several generators or sites to look after
    • You want service dates tracked and a history of the work

    What it involves

    • An agreed schedule, by running hours and by date
    • Inspections, test runs and changeover checks between services
    • Records for every visit
    • Faults found early and quoted before they cause a failure
    Discuss a maintenance plan

24/7 emergency path

Generator down? Call now, then keep it safe.

24/7 operations. We arrive within 1–2 hours, usually within 1 hour. Free callouts and quotations.

Call 076 434 7292WhatsApp us

Emergency generator repair: what to tell us and what happens next

Before we arrive: keep it safe

  • Fuel smell or leak

    Switch off. Keep flames and sparks away. Do not restart.

  • Smoke or burning smell

    Shut down and keep people clear of the set.

  • Overheating

    Let it cool. Never open a hot radiator cap.

  • Will not start

    Stop after a few attempts so the starter does not overheat.

  • Mains off, generator silent

    Note whether the controller is in auto and what alarm its screen shows, then call. Do not keep resetting alarms.

  • Running, but no power

    See whether the output breaker has tripped. Leave the changeover panel to a technician.

Generator problems

Common generator faults we fix

Start with what the generator is doing. Each guide explains the likely causes, the checks that are safe for you to make, and how we repair it on site.

All generator problems

Load shedding and power cuts

Backup power for load shedding and outages

A standby generator is built to start when the mains fails and carry the load until it returns. Load shedding, and the long municipal outages that follow substation faults, cable theft and summer storms, ask far more of it: a start for every outage, sometimes several a day, and running hours that pile up much faster than test runs alone. That applies to home generators and business generators alike.
Yellow Turner Morris silent diesel generator with an ATS panel, installed in a brick alcove
A small silent diesel set with ATS, in a brick alcove where hot air can build up on long runs. Each outage means a start, a transfer to the generator and a transfer back.

What heavy load-shedding duty does to a generator

  • Services fall due sooner

    Service intervals are set by running hours as well as by date. A set that runs through load shedding most days can reach its hours interval well before the year is out, so watch the hour meter, not just the calendar.

  • The battery and charger work harder

    Every outage begins with a crank from the starting battery. While the set runs, its charge alternator tops the battery up; once the mains is back, the battery charger has to finish the job. Frequent starts and heat inside the canopy age a battery quickly, and a tired battery, failed charger or worn starter motor shows up as slow cranking just when the power goes. See battery not charging.

  • Fuel is used and stored differently

    Diesel turns over faster, which keeps it fresher, but every refill from a drum or jerry can is a chance to bring in water and dirt. Running the tank low draws up sediment, and a diesel engine that runs dry usually needs the air bled from its fuel system before it will start again. See diesel fuel contamination.

  • The changeover wears with every outage

    The automatic changeover (ATS) moves the load to the generator and back at every outage, so its contactors and relays operate far more often than in a year with few outages. Worn contacts, a faulty timer or a mains-sensing fault can leave the set running while the building stays dark. See changeover and ATS problems.

  • Light loads cause wet stacking

    A diesel set carrying a small fraction of its rating, such as a large set backing up a home or a half-empty office, does not run hot enough to burn its fuel completely. Unburnt fuel and soot then collect in the exhaust as a black, oily residue. See wet stacking.

  • Summer heat pushes the cooling system

    Long runs on hot Highveld afternoons, in a cramped alcove or a dusty yard, expose a blocked radiator, a slipping fan belt or low coolant, and the result is a high-temperature shutdown. See overheating.

How to keep it ready for the next outage

  • Service by running hours, not only by date. Note the hour-meter reading every week or two and book a generator service when it nears the interval in the engine manual.
  • Put it on a maintenance plan. A maintenance plan tracks hours and dates for you and adds battery, fuel and changeover checks between services.
  • Prove it under load. A load bank test shows whether the set can carry its rated load, and running a lightly used diesel at a proper load helps clear wet-stacking deposits.
  • Look after the whole standby system. On a standby generator the battery, charger, fuel, controller and changeover all have to work together; a fault in any one means no power when the mains goes.
  • Check it safely between visits. Read the fuel gauge, look for leaks and new alarms on the controller, and make sure it is left in automatic mode. Keep hands out of the canopy, because a set in automatic can start at any moment.
  • Refuel and run it safely. Refuel a petrol generator only when it is stopped and cool, and never run a portable generator indoors or in a garage. Electrical, fuel-system and changeover work needs a technician.

Our generator guides cover controller alarms, coolant care, kVA sizing and more.

Call 076 434 7292WhatsApp us

Generator types

Diesel, petrol, gas and standby generators

All generator makes and models. 1 kVA–20,000 kVA capability.

All generator types

Who we work for

Homes, businesses and industry

Photos from our generator jobs

Specialist services

Specialist generator services

All services

Brands

We Service & Repair All Generator Brands

All generator makes and models, from portable petrol units to large standby sets. 1 kVA–20,000 kVA capability.

Brand names and trademarks belong to their respective owners. Onsite Generator Repairs is an independent service and repair company.

All generator brands

Service areas

Where we work in Gauteng

On-site generator repairs, servicing and maintenance across the five regions of Gauteng. Choose your region or town for local coverage.

How it works

From your call to a working generator

  1. 01

    Call or WhatsApp

    Tell us where the generator is, its make and size, and what it is doing. A photo of the controller screen helps. We operate 24/7.

  2. 02

    We come to you

    We arrive within 1–2 hours, usually within 1 hour.

  3. 03

    Free quotation

    We find the fault or confirm what the service needs, explain it, and quote before any work starts. Free callouts and quotations.

  4. 04

    Work and test

    We do the work, then test the generator, under load where the site allows. One-year warranty.

FAQ

Generator repairs, servicing and maintenance: common questions

What is the difference between generator repairs, servicing and maintenance?

A repair fixes a fault that is already stopping the generator working properly. A service is a single planned visit when the generator is due: oil and filters changed, fluids, belts and battery checked, then a test run. Maintenance is the ongoing plan around those services, with inspections and test runs between them and a record of every visit.

How soon can a technician get to me?

We arrive within 1–2 hours, usually within 1 hour, and you can call 076 434 7292 at any hour. If the generator has failed, our emergency repair page explains what is safe to do while you wait.

Do you charge to come out and quote?

No. We offer free callouts and quotations, and you see the quotation before any work starts. Our repair cost guide explains what affects the price of a repair.

Which generator brands and sizes do you work on?

We Service & Repair All Generator Brands: diesel, petrol and gas generators, and the engines, alternators and controllers they are built from, across our 1 kVA–20,000 kVA capability. See the brands we work on and the generator types we cover.

How often should a generator be serviced?

Whichever comes first: the running-hours interval in the engine manufacturer’s schedule, or the calendar interval, normally at least once a year even if the set has hardly run. Our service intervals guide explains both, and the servicing page lists what a service covers.

My generator runs every day during load shedding. How often does it need a service?

Go by the hour meter rather than the calendar. A set that runs four hours a day adds about 120 running hours a month, so the hours interval in the engine manual can come round more than once a year. Book a service each time it does, or let a maintenance plan schedule the services by hours for you.

The engine runs but nothing has power. What is wrong?

First see whether the output breaker on the generator has tripped. If it has not, the fault is usually in how the alternator makes its voltage: a failed AVR, a rotating diode or exciter fault, or residual magnetism lost after a long idle spell. On a standby set, the changeover may also have failed to move the load across. Our guide to a generator running with no power goes through each cause. If you smell burning or see damaged cables, stop the generator and call us.

What should I send when I book?

Your address, the make, model and kVA rating from the nameplate, the hour-meter reading, and what the generator is doing or which alarm the controller shows. Photos of the nameplate and the controller screen help us bring the right parts. See preparing for a technician visit, or send the details through our contact page.

Do you give a warranty?

Yes: we give a one-year warranty. More answers on costs, quotations and approving work are on our FAQ page.

Which parts of Gauteng do you cover?

We work across Gauteng in five regions: Johannesburg, Pretoria and Centurion, Ekurhuleni on the East Rand, the West Rand and the Vaal Triangle. Our service areas page lists every town we have a page for.

Need a generator technician in Gauteng?

  • 24/7 operations
  • We Arrive Within 1–2 Hours (usually within 1 hour)
  • Free callouts and quotations
Call 076 434 7292WhatsApp usRequest a technician

Or request a technician online

Call nowWhatsApp us