Same boiler different badge, go for baxi the warranty is worth it, get it fit correctly to avoid warranty issues, look at baxi platinum its the same but has 10 years
What boiler have you got? On a pressurised system i never touch isolation valves apart from new boilers as when pressure is released an open end wont leak water
Wont fix your problem of banging, probably a duff pump they tend to cut out every now and again causing overheat, hope you know how to check the boiler wont kill you when you put it back together
Wishful thinkin i think! I dont know of a product, if there iswold you really wat to dollop a gluey mixture down the drain? Asking for trouble if you do!
The duo tec can be fit with weather compensation. Even better a baxi platinum is exactly the same as a duotec and its got 10 years warranty for a great price.