Hi all. I have a 4 year old Ideal isar H35 condensing combi. All radiators are permanently warm without the CH or DHW being on. I think it could be a faulty diverter valve. As with most modern combis my boiler fires up occasionally to heat up water via the Heat Plate Exchanger and I think it is this heated water that is being transferred to the rads via the faulty diverter valve. Does this diagnosis sound correct? I am not a qualified plumber and do not intend to make the repairs myself. But, for curiosity's sake, I would appreciate advise on how easy (or not!) it is to replace/repair a diverter valve (and a ballpark cost). Also is there any way to turn off the occasional heating of ther Plate Heat exchanger (short of turning off the boiler completely!). Your advice is always greatly appreciated.