I have a related problem whereby I have a Drayton wireless thermostat system that is controlling a Ferroli boiler. The stat appears to be working fine (i.e. it is sending commands to the unit attached to the boiler) however the Ferroli is very intermitent as to whether it wants to heat the house or not. I have ensured the pressure is at about 2bar.
Any ideas?

Clapham London, June 2009