we have no hot water, new diagphram and heating working but told manifold is blocked and we need to source a venturi cold water key from Vokera to unblock the problem. Any ideas on how much (a) the key would be and if this can't be done (b) how much to change a manifold?
I think they mean the white plastic thing in the domestic hot water manifold. it has two holes in it, and can be unscrewed with a cheap pair of circlip pliers, available at many pound shops, or you may be able to poke out the blockage with a bit of bent wire. For anyone with any mechanical nouse it is simple. Since it is just plumbing rather than gas, and doesnt require draining the CH to get at, you could turn off the electricity and the cold water in, remove the grille underneath and have a go yourself. study the manual first. It could also be that the strainer thimble on the inlet of the section with the DHW diaphragm in has got bunged up.