After switching the setting on my Ravenheat CSI 85AT Boiler to Central Heating and Hot Water (its been set to just Hot Water through the summer and worked perfect in that setting) the Central Heating will not switch on, in either auto timer or manual mode. All the relevant led's on the timer panel are indicating that it is working, however the boiler is not! the hot water setting still works perfect!
I've checked the room thermostat and it's definitely sending a signal to the Main PCB asking for heat.
Does the main PCB need replacing or should I be checking other components first? I would be grateful for any help!

Allan, September 2008

i have the same boiler and same problem and it happens at the same time every year - the boiler is only 3 yrs old!! I seem to think it's because it hasn't been used over the summer and then it just won't kick in. Last year my plumber replaced the thermistor and it worked fine and charged £50. i have just bought a thermistor myself from ebay for £7 and replaced it and it's all looking good!! I bought a hot water and ch thermistor as they are both the same part and replaced the hw one first as it is easier as you just need to turn off your water and electricity supply. it worked but just for a day so i have just replaced the ch one and it has just all kicked in again!! How chuffed am i - had to do it all myself as my hubby is working away!! The ch thermistor requires the system draining so was much trickier but worth it as i am now toasty warm!! thanks Liane

liane, September 2008