Hi all,

We moved into a 1999-built house a few months ago. Currently using a 28kW combi, which isn't great for 3 bathrooms, 2 with showers.
From looking at the plumbing in the upstairs airing cupboard, there has been a cylinder fitted in the past, which was then changed to a combi system in 2015.

Would it be relatively straightforward to have an unvented cylinder added here? Would it simply be plumbed in as part of the central heating circuit, with a zone valve controlling flow to the cylinder coil? The hot water part of the combi could simply be redundant (or could possibly feed nearby dishwasher or washing machine?).

I have added a photo just to show the existing pipework. To my untrained eye, it seems like everything's there that's needed - There’s two pipes for CH flow, which have been joined together. What I presume is the cylinder return has been capped off. There’s a tundish and a 28mm vent pipe which goes outside. On the water side of things, there’s a 22mm cold feed from under kitchen sink, and a 22mm hot feed which will at one point have been leaving the cylinder. There’s also what I think is a 15mm balanced cold feed, which seems to feed everywhere but kitchen. Hope that makes sense.

We have Evohome, so would be looking to add the DHW to that too. One plumber I spoke to by phone said I would still need a cable going from the tank to the boiler, so the zone valve can control boiler. He was insistent that there was no other way, and that evohome couldn’t do it wirelessly - is he right?