I recently visited the home of an elderly couple who have Xefro 'Graphene' panel heaters fitted throughout the house - I was told that they stopped working shortly after they were installed (over a year ago). To cut a long story short, the original sales team made off with the £4k up-front deposit and were never seen again however the second set of installers made a neat enough job - only problem is they left without providing any sort of user manual or the promised controller 'app' for phone/tablet. The system comprises about a dozen radiators grouped into 4 zones. Each radiator has its own wireless receiver, and each zone has a battery-operated wireless controller. There is also a single black box (labelled 'do not unplug') plugged into a 13A socket which I would guess connects to the house wifi system to allow remote control. Anyhow I managed to get the heaters working again by fitting new batteries to the zone controllers, switching on the 'black box' controller then rebooting the receiver controls for each heater by just switching off for 30 secs then back on. What I can't seem to do is to control the zone temperatures - the controllers have up/down buttons but they don't seem to do anything other than display ambient temperature. Has anybody come across these heaters and, if so, do you know where I can download a copy of the user instructions or any other technical data? Many thanks.