Can you take the transmitter off the wall and place it under the boiler and tell me if they resync?
The transformer is fixed to the wall
The transmitter will come off, usually the screws are under a cover
Do you need me to dig out the instructions for you
the receiver RCR10/433 is where the red light is constantly flashing...perhaps you can assist
The transmitter needs to come off the wall and sit under the receiver - can you do this?