Bypass lead pipe taking mains feed straight upstairs?

[EAB77]

Would anyone see any issues with doing this? Looking to replace lead pipe which runs from water main either all the way to stoptap under kitchen sink (back of the house) or possibly changes to new pipe at the kitchen threshold. There are fixed floor coverings in hall/kitchen which ideally we don't want to rip up as will cost a lot to repair.

Couple of guys recommended by local water company (who are happy to change their bit of lead as far as the boundary) have come to quote. Both suggesting that the easiest solution is to totally bypass the internal lead pipe by installing a new stoptap inside the front door and then taking the feed straight upstairs to second floor bathroom. Feed would then flow to first floor bathroom (where the combi boiler is) and then back down to ground floor. Basically reversing what happens now. I'm excited about the flow being better on the top floor as it's rubbish at the moment, electric shower just stops working when you are standing in it if demand is high locally or people use downstairs taps or flush toilets. But nervous about flow at the kitchen sink and drinking water quality.

Has anyone tried/experienced this method and were the results OK?

 

[footprints]

In principle should be fine, but I would fit double check valves ( a non return valve to stop water in the mixer spouts draining back down to the drinking water taps) to the upper taps in case you have, or have fitted later mixer taps, on bath, basin or shower.

 

[EAB77]

Thanks footprints. The top floor shower is electric so I guess that should be ok but yes main shower is a mixer with a very long pipe leading to a head fixed by a plumber who must have been about 8ft tall. So plenty of opportunity for water to run back.

My main concern is the boiler though. As in, if someone is taking a shower on the top floor, what happens if the flow to the boiler is then restricted (boiler on floor below). Will it actually break or damage the boiler or will there just not be any hot water/heating until the shower is over?