I have a Baxi Duo Tec , fitted 10 years ago. No real problems until very recently. My plumber has serviced it every year and most recently two months ago. We put the heating on for the first time since about April just over a week ago. It wouldn't come on. Had no problems with hot water. Plumber comes out changes a part £100 fee. Next day the heating works but no hot water. Plumber comes out £40 fee. Hot water is a bit temperamental for a day, running hot then warm then stops altogether. Boiler starts making clanging noises. Never heard this before. Plumber says boiler system is now 'full of rubbish ' and he will contact Baxi. He says I may need a new boiler? This doesn't sound right to me. Can experienced plumbers please reply with advice.