Being no expert of boilers, well having lived in a shacked with logs :) I'm wondering if mine is on the blink ?
Ok basically its a valiant ? turbo max. Whats happening is it fires up, I turn it up to say 80% for te radiator heat, it gets to it and then slowly counts back down slowly ?
I'm guessing using my powers that its mean;t to maintain it on that heat level instead of dropping down ?