I had my heating on for the first time yesterday, it did not warm up much so went to check the central heating temperature set on the boiler. It was at 38deg, it had been recently serviced and I assumed the engineer had left it at that temperature. Went to turn up the thermostat and the knob fell off in my hand, it would not push back on and was obviously broken. Tried to turn the spindle inside but it would not move. The boiler is a Vaillant ecotec and is 18 months old. The knob must have been broken when the engineer serviced the boiler, not saying he broke it but it would have been obvious so annoyed he did not mention it. I am checking with Vaillant to see if it still under warranty, if not could I change it myself (assuming I can get the part). I am competent to change something like that but it would mean taking the cover off and I know what you Gas Safe engineers are like when taking the cover off is mentioned by a non Gas Safe engineer.