Ensuite Shower losing water pressure

[Merciless]

Hi There

I moved into a property last year (only 8 year old propery) and it has a lovely ensuite on the 3rd floor (4 bedroom semi) as well as a normal bathroom on the 2nd floor.

When moving in, the water pressure in the en suite shower was nice and strong 24x7. Beautiful. The bath and the shower on the 2nd floor also had super strong water pressure.

Over the course of the year, we noticed times where the shower had less pressure. Over time, this got worse and now there's consistently awful pressure in the shower. To put it into perspective, hot water from the bathroom tap takes 17 seconds to fill a large mixing bowl. Hot water from the shower connected to the bathroom tap in the bathroom takes 37 seconds. The ensuite shower on hot only takes over 5 minutes at which point I stopped the clock and gave up as my arm hurt. When I turn it to cold all the way it's also incredibly weak but more powerful than when it's only on hot.

Today I changed the shower head and the pipe from the head to the wall, and it made not a shred of difference (needed a new shower head anyway thus going for it not). I actually unattached the shower pipe from the wall part and turned the shower on and could see the weak pressure water running out.

In the suite there's also a sink and the hot water flows out nice and fast just like it always has.

So at this point I have no idea how to debug the problem further or how to resolve - I've attached a picture of the shower setup, and don't know much about these things - Am I going to have to call someone in here or does anyone have any advice?

Thank you!

 

[Brambles]

Is your hot water system unvented, vented or from a Combi Boiler?

 

[Merciless]

Is your hot water system unvented, vented or from a Combi Boiler?

I'm no expert but I believe unvented.

We have our boiler in the kitchen, then a hot water tank in the airing cupboard on the 2nd floor. That has an immersion heater if needed (but that's switched off) so it's heated by the boiler. We then have a NEST which controls the times the heating and hot water is on.

 

[Brambles]

Start with the basics, measure your incoming flow rate and the dynamic pressure (ie with one cold tap running). That will give you the inputs for the unvented, thereafter you can see what the expected outputs should be.

Much better to start there, before looking at individual shower or bathroom set ups.

If the flow and dynamic pressure is ok - then look at the unvented cylinder - check it has been serviced properly over the last 12 months. If not get it serviced.

If that is ok, then look at the shower fittings et al on an individual basis.

 

[Merciless]

Start with the basics, measure your incoming flow rate and the dynamic pressure (ie with one cold tap running). That will give you the inputs for the unvented, thereafter you can see what the expected outputs should be.

Much better to start there, before looking at individual shower or bathroom set ups.

If the flow and dynamic pressure is ok - then look at the unvented cylinder - check it has been serviced properly over the last 12 months. If not get it serviced.

If that is ok, then look at the shower fittings et al on an individual basis.

I wish I understood half of what you just said 🙂 Though I did think by measuring the flow rate of the hot tap in the bathroom compared to the hot tap of the en suite shower it would give me an indiciation that the problem was specifically with the shower... I'm guessing that's not how it works from reading the below? The boiler/cylinder was indeed serviced 6 months ago and all good on that side.

 

[Brambles]

With an unvented cylinder - the performance of your system is determined by your incoming cold water flow rate (kitchen tap). Buy a measuring cup from Screwfix et al and measure the performance of each tap in the house - not the showers. Hot and cold (other than kitchen cold) should be equal flows if the installation has been piped correctly an the unvented is working properly with a balanced cold supply

 

[Merciless]

With an unvented cylinder - the performance of your system is determined by your incoming cold water flow rate (kitchen tap). Buy a measuring cup from Screwfix et al and measure the performance of each tap in the house - not the showers. Hot and cold (other than kitchen cold) should be equal flows if the installation has been piped correctly an the unvented is working properly with a balanced cold supply

Got it - Purchased a flow cup today (will come tomorrow) so will let you know the results of the various taps in the house. I don't feel like there's been any change in flow hot or cold) in any tap in the house other than the shower itself but will take a look anyway and post here once I've got it. Thank you!

 

[Merciless]

With an unvented cylinder - the performance of your system is determined by your incoming cold water flow rate (kitchen tap). Buy a measuring cup from Screwfix et al and measure the performance of each tap in the house - not the showers. Hot and cold (other than kitchen cold) should be equal flows if the installation has been piped correctly an the unvented is working properly with a balanced cold supply

OK - got the cup and measurements. Results are:

Kitchen cold: 22lpm (max on the cup)
Kitchen hot: 18lpm - very strong
Downstairs toilet cold: 16lpm
Downstairs toilet hot: 16lpm
Middle Bathroom sink cold: 6lpm
Middle bathroom sink hot: 6lpm
Middle Bathroom bath cold: 22lpm
Middle bathroom bath hot: 18lpm
En Suite Sink cold: 6lpm
En Suite Sink hot: 6lpm

Didn't try the impacted shower in the en suite just because it's so weak it won't hit 2lpm on hot or cold (the cold is slightly stronger)

I have no idea what this would mean in terms of judging balance but really appreciate your help/advice here.

 

[Brambles]

Assuming that the dynamic pressure is high enough for the unvented cylinder.

To me, that reads as possibly two issues:
the incoming supply filters to the shower are partially blocked or the thermostatic cartridge has failed.

A contributory factor could also be that the pipework to the ensuite is possibly undersized. A decent shower needs a flow rate of at least 15 lpm - but if you have had that in the past more likely to be a flow restriction outlined above.

From your readings I would guess that the bathroom and ensuite basin taps have been fitted with flow restrictors.

A decent plumber should be able to resolve your issues - albeit increasing the pipework sizing ( if required) may not be so easy. Unless you are confident, I would engage a plumber. Shower cartridges are expensive and if in a hard water area not always that easy to extract.

 

[Ben-gee]

Have you tried disconnecting the hose from the shower outlet and trying the shower like that?

(it could be a blocked head or a herniated hose)

If not, then as mentioned above it is probably filters or cartridge.

 

[Merciless]

Have you tried disconnecting the hose from the shower outlet and trying the shower like that?

(it could be a blocked head or a herniated hose)

If not, then as mentioned above it is probably filters or cartridge.

Really appreciate all the detail.

Yes disconnected the hose from the shower outlet and indeed the water was super weak. I did notice if I rotated the bit that turns the shower on and pushed really hard the water seemed to come out slightly stronger by a touch (but still incredibly weak) but yeh, basically the water softly comes out like if you were pouring water gently from a kettle or something ha.

Indeed for the first 6 months or so after moving in it was very powerful and had no problems at all. Then every now and then it was a bit weak but mostly fine...and then it just took a sudden turn for the worse and became weak 24x7.