ATS repairs
Generator ATS & Automatic Transfer Switch Repairs
We repair automatic transfer switches that fail to start the generator, fail to move your load across, or fail to switch back when the mains returns. The ATS watches the mains, calls for a start and transfers the building between mains and generator. We diagnose each step of that sequence on standby systems across Gauteng, and we make the supply safe before we work on it.
Callout fee waived when you accept our written quote. 1-year workmanship guarantee. See prices
- Start signal and transfer tested
- Contactors and mains sensing checked
- Live boards left to us
- CoC for changeover installations
- Onsite across Gauteng
What the switch is doing
What does a generator ATS do?
The ATS watches the mains. When the supply fails, it calls for a start. When the generator is ready, it transfers the load. When the mains returns, it switches back and lets the generator stop. A failure at any of those steps looks like “the generator did not come on”, even when the engine is fine.
The fault can be a missing start signal, a controller in the wrong mode, a mains-sensing fault, a contactor that does not pull in, control wiring, a failed interlock or a mechanical transfer that does not complete. These are electrical checks on equipment that can be live, so please keep the board closed and let us test it.
If the set starts from the panel in manual and only fails when the mains drops, we start with the automatic sequence. If it will not start in manual either, we test the engine and the battery as well.
When a changeover switch has to be replaced or newly installed, the work is quoted separately. We issue and sign the electrical Certificate of Compliance (CoC) for the changeover switch installations we carry out.
How the sequence fails
Why is my generator not starting automatically?
We find the step that failed before we replace anything, because a failed transfer does not always mean a burnt contactor.
Generator starts but power does not transfer
The engine is running and the building is still dark. We move to the transfer itself: the sensing, the contactor and whether the ATS accepts the generator as a source.
ATS contactor faults
We test a contactor that will not close, or will not drop back to mains. We never bridge it out to force a supply onto the board.
Mains-sensing problems
If the switch never sees the mains fail, or never sees it return, both the start and the changeback go wrong. We test the sensing circuit and its settings.
ATS and generator controller communication
The controller and the switch have to agree on start, ready and transfer. We read an alarm on one and a silent switch on the other together.
Commercial ATS repairs
Offices, shops and complexes often depend on this sequence. When you book, tell us how we reach the switch and who will meet us on site.
Testing automatic operation
We prove the sequence in the order it should happen, because a manual start alone does not prove the mains-fail path.
Related Pages
Automatic start, controllers and callouts
- Not Auto Starting Mains fails and the set stays still
- Not Switching Back Mains returns, the set keeps supplying
- Controller Repairs The module that issues the start
- Control Panel Repairs Wiring, relays and the wider panel
- Generator Installation Changeover as part of a new install
- Changeover Switches Manual changeovers and the CoC
- Changeover CoC Guide Certifying the connection
- Generator Callouts Book the site visit
Common Questions
Questions about ATS repairs
What is a generator ATS?
It is the automatic transfer switch that starts your standby set when the mains fails and moves the load between mains and generator.
The generator does not start when the power fails. Is that the ATS?
It can be. A missing start signal, the controller mode, a battery fault or an alarm holding the start off can all cause it, and we test each one.
The generator starts but the lights stay off. What does that mean?
The engine has started but the load has not transferred. That is a transfer fault, not a no-start, so we begin at the switch.
The mains has come back and the generator is still supplying. Can that be the ATS?
Yes. A failed changeback is a separate step from the original start, and it often sits in the mains sensing or the contactor.
Can I bridge the switch to get power on?
No. Forcing a live board or defeating an interlock is dangerous and can feed power back into the mains. We diagnose the transfer with the supply made safe.
Do you repair the controller as well as the switch?
Yes. When the start command or the alarm sits in the controller, we test and repair that module in the same visit. Wider panel wiring falls under our control panel repairs.
Is ATS work part of an installation?
A new changeover can be part of an installation. ATS repairs cover a switch that is already installed and is not completing its transfer sequence.
Do you issue a Certificate of Compliance for changeover switches?
Yes. We issue and sign the electrical Certificate of Compliance (CoC) for the changeover switch installations we carry out.
What should I send about the transfer switch?
Tell us whether it fails to start the set, fails to transfer, or fails to switch back to mains, and send a photo of the controller screen if it shows an alarm. We are open 24/7 and arrive within 1 hour when a failed changeover leaves you without power.
Still unsure what the fault is? Call or WhatsApp 082 057 4605 for onsite diagnosis.
Service Areas
Onsite visits across Gauteng
We come to your generator anywhere in Gauteng, 24/7. Choose your region for local suburbs, call-out details and the faults we see most there.
What to send before we attend
These details help us plan the visit and bring the right parts. Send what you can on WhatsApp; if you can’t find the model number, we still book the visit.
- Location
- The suburb or site, so the visit can be booked in the right area.
- Make and model
- The generator brand and model, if they are known.
- kVA
- The size printed on the data plate.
- Fuel type
- Diesel, petrol, LPG, natural gas, or dual-fuel.
- Controller model
- The module name on the panel, when it is visible.
- Fault or alarm
- What the set does, and any text on the screen.
- Photos
- The generator, the data plate, and the controller or alarm. Send these on WhatsApp.
Book a Visit
Tell us what the switch did
Say whether the generator started and whether the building transferred. Please keep the board closed until we arrive.
- Call
- 082 057 4605
- Message us on WhatsApp
What happens next
- We reply with questions about the generator, or to book a visit.
- A technician comes to you. For a breakdown we arrive within 1 hour.
- The fault is diagnosed on site and you get a written quote. No work starts until you accept it.
Charlie, lead technician: Degree in Mechanical Engineering, Degree in Electrical Engineering, Diesel Plant Fitter. Generator specialists since 2000.