Rot.
How can an intermittent RF link have anything to do with the fan needing lubrication? These fans do not require lubrication anyway.
RF units can be a bit tetchy. It's not that you have to work on "line of sight" between the receiver (the bit on the boiler) and the transmitter, but you do have to remember that certain materials do funny things to RF signals. For example, you can't expect it to transmit through several thick (brick) walls, and the signal will bounce off mirrors/glass etc so hanging a mirror up in the path of the signal can stop it working. Siting your room stat is really important, so try removing the DT20 from the wall and using it elsewhere for a week or so (nearer the boiler or in another room) and see if a different location helps you.
Other RF equipment can interfere with it too - e.g. wireless doorbells, cordless phones - and if all that doesn't help, well, sometimes RF stats just don't work in some houses and you may have to go hard wired.
Bunslinger, January 2010
