Day one, 2:10 p.m.
The client called because the bottom right panel went black and came back twenty minutes later. It happened again the next day at almost the same time. By the third day two panels were dropping out. Nobody touched the wall. Nobody changed the content.
Day two, 9:30 a.m.
We opened the service hatch and put a thermal probe behind the panels. Ambient behind the wall was 58 degrees Celsius. The panel exhaust was 71 degrees. The room was 24 degrees. The wall was installed with a 15 mm gap against a plasterboard cavity that had no ventilation at all.
What the installation drawing said
The drawing specified a 60 mm minimum clear space. Nobody measured it, because the bracket depth itself was 55 mm and the installer assumed that counted. It does not. The gap has to be clear air behind the mounting surface, not the distance from the wall to the panel.
The fix, in one afternoon
- Moved the frame forward 80 mm using extended standoffs.
- Cut two 300 × 150 mm vents at the top of the cavity and two at the bottom.
- Added a small low-noise fan at the top vent, rated 42 dB at one metre.
- Re-ran the temperature log for 48 hours.
Day three, 4:00 p.m.
The client asked whether they could close the vents because the fan noise was audible in the reception area. We moved the fan to a remote location above the ceiling and ducted it. The lesson is that ventilation design has to include where the heat and the noise go, not just that a hole exists.
What to put in the drawing
A dimension, a vent area in square centimetres, and a note about the noise path. If it is not dimensioned, it will not be built.