Any plumbers on here or people who have had the fun task of replacing a boiler?

The current boiler is about 20 years old and whilst it works well for the ground and first floor it doesn’t make it up to the second floor so great (crap water pressure from the hot in the sink and bath).

I’m planing on adding a second bathroom on the ground floor so it’s going to be too small anyway to cope with 2 showers at once so it seems a sensible time to upgrade it first.

Anyone got any recommendations for boilers suitable to the task?

My mate lives next door and he said when they ran the pipes they are a fairly small diameter of plastic pipe so not sure if that will be an issue.. however I’d have thought a smaller diameter pipe would be good to keep up pressure?

The cold water seems to run up just fine.

Cheers!?

I’m no plumber, but I will try an steer you on this.

Are you looking for a combi boiler or a system boiler. If you have rubbish mains pressure then a combi boiler most likely will not help you unless you can find one that has a small HW storage tank. Even with one of those you need to consider the flow rate of the 2 showers. If they are both heavy liters/minute then you may find it difficult getting a combi boiler that will provide enough liters/minute to satisfy the shower demand.

Is the current boiler a combi?

Edit.

If you have the space and money I would get ahead of the game and go for a Hybrid air-water with gas back up.
I put a brand new Worcester Combi in two years ago which runs fine but if I was doing it again would go hybrid.

waste of time mariner.. your fancy boiler will need replacing and we ll still be fitting millions of gas boilers.

fit a big 42kw combi for the demands of two showers or a non vented system for mains pressure hot water. replace all pipework with modern plastic 15mm minimum. end of.

All boiler manufacturers make a Combi that will cope but the cold main supply needs to be able to supply enough water, flow rate crucial.
Are you on an old lead main?
Check what you are getting at your kitchen cold, fill a bucket and time it, if you have less than 20 litres per minute you will struggle.
You may need to consider a new mains supply flow Waterboard’s stop cock.
Alternatively you can install an accumulator, there cumbersome and expensive.
Before you do any of that make sure ALL valves are fully open and there’s nothing restricting the current flow.

I think the water supply is good (cant test until I’m home next month). mid 90s house with plastic pipe coming in and the utility room tap next to where it comes in fires out cold water very aggressively!

Upstairs (3rd floor) the cold water tap is fast too but the hot struggles.

The pipes are plastic but I’ll need to measure them I do think they were on the thinner side than what they should have been (according to the neighbour).

Currently it is a combi. I’ve googled what an unvented system is.. is that likely more powerful than just directly from the combi then? I’ve got no tanks anywhere at present.

The unvented system is simply cold water fed to a tank that is then heated? So I don’t need a new boiler per say?

It would mean losing space in the garage though which isn’t ideal but not impossible…

If the mains supply is good should I just go for a big combi like totalshell suggests?

I’m going to try some full bore isolating valves first too.. hopefully they are part of the issue.