F
Flo
We had a new condensing "VOKERA COMPACT HE" boiler installed a few years ago .unfortunately the company went bust so we can't ask them.the first winter the roof vent almost froze right up .the icicles hanging from the vent were extensive.the boiler never stopped working so I hoped it would if the vent eventually became frozen shut....is that correct .? Anyway during the last cold spell I decided to keep the boiler on low and on all the time but it didn't matter .the vented fumes still turned to water then froze over.i have no idea why nobody else in the street with a roof vent seems to have this bother and why doesn't the vents on other people's houses that are fitted on side walls have similar problems......