Pumping the whole house

[Steth]

We have two electric showers. One has died, the other has never been good for more than a warm dribble. (Ditto the hose off the bath taps). Technology appears to have moved on in 20 years!
Can I 'pump the whole house'? I'd like to put a pump on the feed from the (twin) hot water cylinders. I'd then run a hot feed to both showers (which already have mains cold) and replace the showers with thermostatic valves, gaining a decent shower in both places as well as the bath.

If I also pumped the feed from the cold tank, I assume I would then get a bath that fills faster and keeps up with the hot. (Again thermostatic taps planned)

Are there any problems with this plan?

 

[meldrew's_mate]

\seth, it seems a lot of work to get more flow when you may not have considered all of the more "conventional options. The main problems I see with pumping as you describe are unbalanced supplies (pumped hot, mains cold) at the showers, and noise from the pump(s) at night.

Have you considered / have you space for a CWS tank in the loft at a higher level. For most showers 1m from the highest shower outlet (spray head) to the water level in the CWS tank is the minimum, anything higher is a bonus. Next run 28mm (1") pipework independantly down to each DHW cylinder, and the same off the top of them at least until the shower supplies have tee'd off. Likewise the cold supplies from the tank should be 1" until the shower outlets have been tee'd off.

If you're still insistent on pumping look at the Grundfos web-site, and remember not to fall foul of the water regs (anti-backflow devices).

 

[Steth]

Thanks for the useful info. Sadly, running 28mm pipe isn't an option due to the locations, whereas running a short length of hot from the nearest basin is. The cold tank cannot be raised by any significant amount. Noise wouldn't be a problem with the proposed pump location. On thinking further about this, as the hot water cylinders are supplied by the cold tank, I would probably only need to pump the outlet from the cold would I not?

Modern shower valves appear to cope with fluctuations in water pressure so I'm assuming that they would work OK with mains cold and pumped hot. Thanks for the warning about regs and anti-backflow devices.

I guess what I'm really after is whether there are any problems with a previously low pressure system becoming a high pressure system. Do cisterns still stop filling when full? Do the washing machine and dishwasher still cope? Do your teeth blow out when cleaning them???

Any info gratefully received.