Faulty dimmer?

I bought a house with CBUS installed and everything worked for the past two years. About a week ago, suddenly, the whole system became unresponsive. Couldn't turn on or off lights, using switches or color display unit. I had to kill the power at the main breaker to bring the system back on track. Later on the day I found that several groups of lights don't hold when they turn on. After some time they turn off while the switch indicator still lit. Further investigations showed that all the light groups connected to the same dimmer unit have this behaviour, eventually turning off themselves after some time. The time varies from 10 seconds to about 3 minutes. All the other lights and units in the home are working as normal.

It looks like a faulty dimmer unit but want to know any other possibilities that can cause this type of behaviour before replacing the faulty unit. Didn't do any changes in the CBUS system for a long time. But, about a month ago, we installed a 3kW solar system with SMA inverter and not sure whether it has any effect on the system.

PS: The CBUS voltage is around 27v. The faulty(?) dimmer is 8 channel with a power unit.

 

Have you made any changes to the lamps recently eg replaced halogen with LED?

 

I changed most of the halogens in the house to LEDs more than a year ago and nothing is done recently.

 

27V is OK.
Find your dimmer model number and download the installation instructions from here
http://www2.clipsal.com/cis/technical/product_groups/cbus/output_units/din_rail_dimmers

The lights shutting down on only one dimmer unit could be an overload.
The LED indicators on the dimmer unit can help diagnose that and other problems.

 

The dimmer model is L5508D1A. All the lights are green including the channel LEDs. I noticed that when the lights turn off, the cbus indicator and unit indicator turn off for half a second along with all the channel indicators like the dimmer is 'rebooting'. I turned on channels one by one and possible combinations to isolate any channel's contribution but the result is same for all channels.

 

Get an electrician to check the integrity of both the 240v supplies to the dimmer.
If the CBus 240v supply drops off, depending on your number of power supplies it could make the whole network unresponsive.

If the 240v briefly drops out the dimmer may resume to off state depending on the programming.

 

Thanks DarylMc & NickD for the replies. Every test I did, lead me to assume the dimmer is faulty. So I replaced the dimmer unit with a new one and everything is working normally now.