I had a Baxi combi 80e boiler installed about 3 years ago. The HW is working fine but the CH has stopped working. No warning lights are on and when the CH is turned on the boiler does absolutely nothing in response. I have it serviced every year but the chap who does it is away. I have spoken to him and he told me to try bypassing the timer unit as I am fairly technically competent. I have done this and it's still the same. Any one got any ideas please?