Idea for a new boiler and better shower pressure

[olliewills]

Hello all,

Apologies in advance but this'll be another question about shower pressure!

My partner and I have just moved into a 1980's 3-bed semi and the shower is basically a dribble. Even without the hose/head the water basically trickles out. Our hot water comes from a rather aged traditional gas boiler with small hot water tank in the airing cupboard and expansion in the loft.

The shower a is a thermostatic type with the little red tab. the pipes for hot/cold run have been run up into the loft before coming back down to the tank in the airing cupboard(HW tank and shower are both on the 1st floor). It seems as though the shower is currently fed hot from the negative tank and cold from the expansion as both feeds have equally poor pressure. Every other hot or cold tap in the house is capable of producing a more than acceptable flow.

I've done my research and I have a plan which I wanted to run by people here before going off to get quotes on the work. At present, the flow rate of my garden tap is ~24 litres per minute (Filled a 10l bucket in 25s) and the static pressure is 4 bars. Dynamic pressure dropped to just above two bars with the kitchen cold tap almost fully open and ~3 bars with the kitchen tap partially open at a point where you could happily fill a kettle or wash up without worrying.

My plan is this:

• Remove the old boiler and have a new Bosch combi installed, currently thinking of a Greenstar CDi Highflow either 440 or 550(the big boy!) to make the most of my pressure/flow rate.
• Have a Wave Smart controller fitted and paired with the boiler
• Have any relevant internal pipes up-rated if people think it necessary
• Possibly have a new shower installed if the thermostatic mixer won't place nicely with the new boiler
• Ensure all cold water is drawn directly from mains supply (i think that's a given with a combi but wanted to check)

By doing this I'm hoping to achieve the following:

• More economical and customisable energy usage
• Never having to worry about how much hot water I have
• Have a nice powerful shower which suits both myself and my partner
• Having scope to provide heat/water pressure to future extensions to the house such as another bathroom
• Freeing up space in the airing cupboard for storage

Do people think my idea is sound and would get me everything I'm after? I'd also appreciate it if people want to give me a rough idea of costs involved, thought I know that's hardly easy. On that front, I should say the house has had cavity wall insulation added and only recently had all the radiators replaced.

Thanks everyone, return-questions welcome!

Ollie

 

[muggles]

It sounds like you have a shower problem rather than a hot water problem if that's the only outlet that's not working correctly. I'd be getting that looked at before jumping into getting a new boiler.

As for going for a Wooshitter 440/550, that's all well and good but bear in mind that the quoted flow rates are only available until the small internal store runs out, after which you end up with a much lower flow rate. It's a compromise between a standard combi and a more traditional setup, and is arguably the best of neither. With your quoted mains performance, you'd be much better off keeping your existing boiler and switching to an unvented hot water cylinder, which you could have in the loft if you wanted. This would give you mains pressure hot and cold water, and you'll never suffer from a tiny internal boiler store running out as the boiler struggles to keep up with demand. It'll also almost certainly be cheaper to do than replacing your existing setup with a 550 - typical price of an unvented cylinder is around £650, typical price of a 550 is around £2300