Hi there. 2 days ago we had a combi boiler fitted in place of a conventional system. Hot water runs hot, whenever we want it.. amazing. Heating works too. Its not cold yet, but im sure it will be very toasty in the winter that is fast approaching. HOWEVER i have 2 issues.. they may or may not be related. First off, i should mention that the boiler is a alpha eco tec 28 (or something to that degree ) Problem 1 : we havnt tested this ALOT yet.. but... It seems that with heating off (or, more accurately.. thermostat not asking for heating) and running hot water, the rads heat up. Surley this iant right.. but what can cause it? A quick google suggests a driverter valve, similer to the 3 port valve in the old conventional system. But this boiler is brand spanking. Problem 2 : only really mentioning this incase somehow its related.. but a radiator downstairs, in the kitchen dosnt bleed at all. No rush of air.. no water. My GUESS is that its blocked up with gunk and sludge.. and il need to close off the valves.. take it off the wall and get the hosepipe on it in the garden. Probbaly brought on by the draining of the system?