Replacement DHW and Heating, Dublin: Vented, Unvented, Combi?

RDWRER_

House reno and need to replace an old system. Water pressure seems pretty poor (Dublin), so my thoughts are this rules out combi or a new unvented tank, unless I go down the route of a mains pump?

Current set up:

• Vented system, header tank in loft and hot cylinder in the upstairs press.
• Shower is electric and gravity fed from header tank, hence awful.
• Central heating is odd. It is pumped, there is no F&E tank, looks like someone retrofitted an expansion tank at one point instead. But the system is still 'fed' by the header tank in the loft and permanently open. The pressure gauge is 0.25bar or something, which I suppose is just the pressure of the head above it. I've seen this referred to as "semi-sealed" but doesn't seem very common...
• No heating zones or thermostats, just on/off and the hot water tank is on the same circuit as the rads which is not ideal.

Proposals:

• Pipework, tanks and rads are ancient and need replacing. Easiest option seems to me to be to keep the vented hot water system.
• Seal the central heating system properly, remove connection to header tank, install a filling loop off the mains and get a proper 1 bar system going. New pipes and rads as I do this.
• Zone it correctly, S plan with hot water and heating zones. New hot water tank etc.
• New shower with a pump, fed from hot cylinder and header tank. Do away with electric shower which is hopeless.
• Boiler is a few years old so will need replacing eventually but not urgent now, it works fine. With this method I can upgrade the system and do the boiler when needed.
• Problem is we could do with removing the upstairs press to give more space in the bathroom. We are thinking of a utility room somewhere downstairs but then I see issues with pumping the water up for the shower? Anyone have an ideas or done something clever themselves in this regard?

Other options are either a new combi or an unvented tank in the garage. Problem I foresee is that these are mains pressure and the pressure around here seems hopeless? Does anyone fit combis or unvented tanks in Dublin? I've read that some do it with those mains pumps that are 12l/minute and noisy.

Thanks

Lenar3556

I wouldn’t rule out the combi boiler. It might be a good solution for what you want to achieve.

The mains pressure won’t be an issue if you pump the supply to the combi (and cold feeds) from a storage tank either in your attic or garage. The DAB EsyBox mini are a decent constant pressure pump for the purpose. They modulate up and down to maintain the set pressure regardless of the amount of water you are drawing off. It’s really the only correct way to do a combi even if mains pressure seemed decent.

Mains booster pumps I wouldn’t be a fan of.

RDWRER_

Thanks, I'll look in to that option too.

It occurred to me the other day that with poor water pressure I might not even be able to fill the central heating with a loop from the mains to near 1bar. That could force me to keep the system running on head pressure alone?

Lenar3556

https://www.boards.ie/discussion/comment/121338411#Comment_121338411

You can use a small hand pump for that if necessary.