Like the gent Mr Findlay on a nearby thread here. ''No hotwater Space heating OK'', my system has no hot water now but radiator line fine. The system I'm investigating is my Mums, installed early eighties. and has only one cistern honest! It is an indirect system just like the drawing on this site : 4 connections as described. I first got involved when my Dad was dying. Mum was trying to run a bath for him I gave her a hand with him noticed hot bath water was all brown. She was'nt even for trusting the water from the mixer taps. It turns out for years, shes been running up and downstairs to get drinking water from the bathroom. Also the heating was defective. I diagnosed radiator system blockage and tried to add Fernox - nowhere to add it! The one cistern is a big 'un and tops up the cylinder. I drained the whole crud system. Got the radiators up and working last winter by allowing flushing out by selective radiator removal. No drainout plugs. Full of black gunge. Now just freshwater. Theres still no inhibitor in there but it's working. Summer is here I'm redundant, not so sure I trust plumbers anymore, so its time to sort out this crud.
Disconnected convective hot water return to boiler after sealing off cistern and cold water into the house. Got a cylinder full of water down there not just the water from the ''primary circuit''. Finished draining down system. Disconnected cylinder. Full of brown crud and any water put into the primary circuit comes straight out the bottom hot water outlet. Therefore cylinder goosed by corrosion due, no doubt, to no inhibitor.
Now I'm a (ships) electrician, not a plumber and I'm not too keen on a profession that inflicts this crud on trusting old people!!! I would'nt do it! A system patently designed to fail. What I would like to know: where is the best place for me to retrofit this crap system with a suitable cistern to allow me to top up the primary circuit and radiator system with inhibitor, fit vent and the rest of it. I've ordered a new cylinder etc. I want to leave this system so my Mum can trust it and drink the water, and stay warm without getting Legionaires disease. Not just for her, but to spite Gordon Brown because he'd love it if all pensioners croaked as it saves money.
PS: Boiler is a Baxi WM551OF. No, I don't want to change it for a combi. Any well meant advice welcome. I've bought a book on central heating but its ''fuzzy'' on the cistern subject.
Cheers.