With all mains pressure appliances: combi, thermal store, unvented cylinders, it is best to have a 22mm full bore stoptap and a 22mm all the way to the appliance with no tee offs on this pipe. Even if the main pipe is 1/2". An old 15mm stoptap can really reduce the flowrate, as can 15mm cold fee with lots of elbows. In borderline installations I have always done this and the flowrates have improved, and usually by around 20%, to what was before. The 22mm cold feed pipe to the appliance generally means that the appliance is not robbed of flow by other cold outlets being turned on.
The Torrent is a great cost effective alternative to an unvented cylinder, although I like the Range models with plate heat exchangers better, as they have a quicker recovery rate. The Torrent does not really need to be run at 80C. It can be run at a lot less and be effective, dending on DHW usage. The hotter the temperature the more energy is stored and it will last longer. I fitted a Newark thermal store, and used a Remeha Avantaplus boiler with dual temperature control. I think the range is all dual temperature. It is a DHW priority. The three way valve is controlled from the boiler and the cylinder thermostat is wired into the boiler as well. When there is no DHW calling the weather compensation takes over on CH using pretty low temperatures most of the time. Works very well. giving full boiler temperature on DHW reheat, so DHW is back pretty quick. I like these boilers. They are cheap enough and work well and not nastily made, in fact quite well made.
