Problem started with cHtg not coming on. This was Friday apprx 2.00 pm. Rang Corgi who sent two engimeers on Saturday. Had my suspicions about them right away, didn't even wipe there feet! They said it was a faulty prgrammer. Came back Monday and took them 3 hours to install! Still not working! Rang Corgi and they sent an engineer from Vailliant. He checked the boiler, said it's ok, left. Rang Corgi again. This time(Weds pm) guy turned up from Heywood Gas. Said it was a faulty diverter valve. Returned Thur am and fixed it. C/htg still not working. He said no power to the pump, but he wasn't an electrician (very common problem with c/htg engineers). Rang Corgi again. First electrician arrived scratched his head and left! Rang again! Second electrician arrived and at least temporarily gave me heating/hot water tilll he arrived back on Friday and installed another new clock. Eventually it worked! One week with no heating/ hot water in freezing conditions. Six visits from eight so called engineers and fifteen phone calls. Absolutely dire. Avoid. I'll cancel Corgi and go with Homeserve.