The hardware is fine, the programming is not
One key is dead while its neighbours work, or a key does something other than what it says on the label. Nothing has failed here. The system is faithfully doing what it was last told to do.
The key is not assigned to the group you expect, or its assignment was changed or lost. This is a configuration problem, not a hardware fault, and no part needs replacing.
How a system ends up like this
Three routes, and they are all common in houses over ten years old. A unit was replaced at some point and never fully programmed, so it took on default behaviour. Someone made a change years ago, saved it, and never wrote down what they did. Or the system was commissioned with keys that were always intended for a stage two that never got built, so they have never done anything at all.
There is also a fourth that catches new owners: the key does exactly what it was programmed to do, and the label is simply wrong. Engraved labels get reused when plates are swapped, and a plate that came off a different wall brings its old engraving with it.
Why this is the cheapest verdict in the tool
No electrician, no isolation, no parts, no wall opened. Somebody connects to the network, looks at what that key is assigned to, changes it, and saves. On a system with an intact project file this is a short job and can often be done in the same visit as anything else you need.
- With your project file
- Fast. The integrator opens your configuration, sees the key, sees what it points at, and repoints it. Names and scenes are all there to work with.
- Without your project file
- Slower. The network has to be scanned to rediscover what exists, and the structure rebuilt enough to make a safe change. Same fix, more hours in front of it.
- What is never needed
- New switches. If the plate lights and reacts, the hardware is doing its job.
Nothing on this page asks you to take anything apart. Every check here is done by looking, or by pressing buttons that are already on the outside of a wall plate. Opening the hinged door of your switchboard to see the breakers is normal and fine. Removing the panel behind them is not, and neither is unscrewing a wall plate or lifting the cover off an enclosure.
In Australia it is illegal to work on fixed wiring without an electrical licence, and the reason is not paperwork: the terminals behind a C-Bus wall plate can be sitting at mains voltage. Anything past the faceplate is a job for a licensed electrician, ideally one with C-Bus accreditation.
The one thing to sort out first
Find out whether the project file exists before you book anyone, because it changes the shape of the job more than any other single fact. Ask the previous owner, check the house documents folder, and look on any old computer that was in the house. The lost project file page covers where to look and what recovery involves if it is genuinely gone.
Worth doing at the same time
If you are paying someone to connect to the network anyway, the marginal cost of fixing every other annoyance is small. Walk the house first and write down every key that does the wrong thing, every scene that is not quite right, and every timer that fires at a silly hour. Handing over one list is dramatically cheaper than four separate visits, and it also produces the documentation the house has probably never had.
Got a list of things that do the wrong thing?
Send it over. Programming changes are what we do most, including on systems where nobody has the original files. We will tell you first whether your list is one visit or several.