DIY Doctor UK DIY Forums

Hi all, I know I need to go back to the tradesman who fitted this but I would like to have a reasonable idea what the issues are and how they should be overcome before I speak with him. We have a gravity fed hot water system with a loft cold tank, an immersion in the airing cupboard, and a gas boiler. There was an existing shower pump in the airing cupboard serving a mixer shower in the family bathroom, and we had an ensuite with a bath but no shower. We have now had an Aqualisa Quartz mixer shower installed in the ensuite, which has a digital controller with mixer pump and diverter in the loft. We were told this would work fine along with the existing shower in the family bathroom. All good, until someone tried to use the original shower at the same time, then no water comes to the original shower. Looking in the airing cupboard it appears hot and cold for the new shower have been taken from the pipes just before the pump for the original shower, which to me seems wrong as I would expect that might cause this problem. Is it as simple as that, and what should be done? Here's a photo of the connections.
Thanks in advance.

Remove the white plumbing and fittings.

Disconnect the original plumbing from the original pump.

Fit T pieces to the pump feeds and reconnect the two pumps to the straight part of the T piece. This will ensure a common pressure and flow capability to each of the pumps.

Thanks for that solution. With 2 pumps still trying to pull water from 1 pipe (on both hot and cold sides) would there not still be a risk one pump may end up running dry? Would it be better for the new pump to have its own direct supply from the cold and hot storage tanks?

I have looked again at your photos. You say that your new shower is fed from a pump in the loft, but the 'new plumbing' which I take to be the white items is beside the tank, presumably at first floor level. I guess what is happening is that the existing pump has an easier task of pumping water than does the new one THAT HAS TO LIFT THE WATER to the loft again at the time the original pump is working to remove the supply all of this with a restricted supply due to the manner of connecting the new piping. I dont have a problem with the pump in the loft - although not ideal - but equal flow rates and flow resistance are important.

My prime advice would be to recall your so-called plumber and get him to solve your problem.

For you, the advice I would give is that his solution should be to remove ALL the plumbing feeding both systems, fit a large T piece directly onto the top of the copper tank, and re-plumb the two pumps using no shared piping in the largest gauge pipe available. This should solve most of the problem, although I dont have first hand knowledge of the pump system in the loft.

Suggest you dont tell him how to do it, but dont settle for anything less than total separation of the two systems.

The same applies to the cold supply.

Best of luck with the guy who pretends to be a plumber, remember you make your own luck!