Low water pressure in shower

DC81

Hi

6 years ago we renovated our 70s family bathroom and added a dual pump for the shower which created a lovely power shower experience. We had a 20 year old boiler in the kitchen, hot water tank in the airing cupboard, and a cold water tank in the attic. Yesterday we started some more house renovations and have had the boiler replaced with a combi-boiler and installed in the attic. The heating engineer assured us that this combi-boiler would be fine for a family of 4 in 1 bathroom / 1 downstairs W/C house. They removed the hot and cold water tanks and the shower pump which we had no idea wouldn't work with a combi boiler. Spoke to the plumbers who assured us that as it now runs of the mains water pipe, the pressure should be fine with very little difference to the shower. Last night when having the first shower with the new system, we both noticed that the water pressure was significantly weaker which left us very disappointed. Spoke to the plumbers this morning who are finishing off the job and they said that they thought we wanted a combi-boiler and that if they had known the shower pressure was a priority, they would have recommended a different system completely. They suggested that we could fit an unvented hot water cylinder to improve the shower power but they would need to change the pipes to 22ml and reinforce the floor in the loft for the cylinder. Looking online, it seems that retro fitting this wouldn't necessarily increase the power of the shower as it is limited by whatever flow rate is coming in from the mains supply and won't improve it beyond what is already there. We don't want to throw good money after bad - has anyone got any advice / suggestions as to what we can / should do - if anything - or are we destined to have disappointing showers for the foreseeable?! TIA for any helpful suggestions.

dnpark38

We have had a condensing boiler fitted and before installation they checked the cold water pressure. Afterwards we asked another installer to remove our electric cold water fed shower unit, he again checked water pressure was correct. A shower unit fed by both cold and hot fitted and is very good.

Nothing was complicated but your system seems very complicated and very different in design and installation.

Hope others can advise you on your way forward.

FreeBear

An accumulator (and possibly a pump) might solve the problem - Basically, a storage tank that can boost the flow in to the boiler. Downside is you need somewhere to install the tank (loft would not be suitable).

doodling

Hi,

The question you need to answer is why is the performance of your shower disappointing?

Is it because the combi can't heat the water quickly enough, it is because the mains cannot deliver the flow you want or is it because of restrictions in the flow between your stoptap and the shower?

Your previous system wasn't limited by the boiler performance or the mains flow / pressure, the new system is limited by both.

If the boiler can't heat water quickly enough then the solution is a bigger boiler or a stored hot water solution. If the issue is mains flow/pressure then the solution is water storage and a pump. If the issue is both then the solution is something very similar to what you had before. If the issue is restriction in the flow then the answer is to remove those restrictions (although it should be noted that a combi boiler will inherently restrict the flow to some extent).

This needs some careful investigation before a decision is made as it is quite possible to fix a problem you didn't have and not fix the one you do.

Martyn1981

Possible 'cheat' solution, might be to try an aerated shower head. We got one of these and they feel much more powerful, without using any more water, or even less. They are cheap, but you can of course spend a lot if you want.

For want of a better description, I've copied this:

An air injection shower head (often called an aerated or air-induction shower head) continuously pulls ambient air into your water stream via a built-in Venturi valve. This mixes air with the water to create larger, lighter, and more voluminous droplets, providing a high-pressure, spa-like experience while actually consuming less water.