I had a plumber today no heating in my house, no rads just copper cylinder. He is putting in 8 rads double, oil tank, 26kw Enviromax condensing boiler, Grant backboiler. I asked him could he put in the zones up stairs and down stairs said he couldnt with a back boiler??? Also i asked him to put in a switch just to heat water during summer months from oil said i would have to turn off all rads to do that. I said i didnt i didnt want to be messing with rads etc. Having to airlock them etc. He said there could be an explosion if switch was left on by a mistake or electricity was cut off. I spoke to a man in work he has a boiler stove heading rads and oil heating. Has switch to heat water only from oil and also zoned up and downstairs its sauter control panel system. I am getting thermo stats on each radaitor. Can some one please shed a light. Thanking you.