This is a 12yo boiler and has been very reliable - until now. I accept its probably on its way out but cant afford to replace it right now. The hot water wasnt so I replaced the heat exchanger which was furred up. Got hot water back albeit with much gurgling/cracking noise from boiler. Couldnt run hot water for long before boiler protesting. The CH also wasnt working very well. Rads upstairs mainly hot but only a couple downstairs warm and rest cold. Climapro2 is connected and working. All rads bleed and there is a magnetic filter fitted. Boiler is downstairs in the kitchen and the rad in the kitchen is cold. The old pump impellor moved freely. I had a spare new pump assembly which I fitted as it includes the auto bleed. I think the noisyness was trapped air. I also replaced the internals of the shuttle valve. The new pump is set to maximum. The boiler is now quiet but the CH is still the same. I notice that on the display the "flame" symbol doesnt move off minimum with CH running. Any ideas peeps? Thanks in advance.