I have a Drayton Digistat RF2 wireless system and cannot fire the central heating up , the boiler works ok for hot water but when I turn on the central heating up via the wireless system nothing happens although the sender shows the flame as the heating being on its not,looking at the instructions it says check batterys on the sender but they appear all ok with a good display on them but when I go to the receiver there are no lights on it at all ..the instructions say the red led will flash for 7 seconds every 5 mins it is no doing that, nor can I use the override system , it appears totally dead although when you put hand pressure on top of the reciever the red led lights up very dim...is there any fuses inside the reciever or is it totally knackered