I have a Honeywell 6300 central heating and hot water controller that is faulty. I have read that the Honeywell 9400c is a direct replacement and will screw straight onto the existing back plate. Does this mean I could do the job myself of will it require an expert?
Can you relase the old unit from the back plate? Can you open the box containing the new unit? Are you able to take the new unit from the box, put it onto the backplate and secure it? If the answer to any of the above is no, then get someone in