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Hi there, the water flow in our shower has reduced considerably since we bought our house, meaning the hot water tends to cut off after a minute or two; the shower is fed by a combi boiler: Worcester Bosch RD532i, about 17(!) years old I think. I can't really say if the water pressure in the shower reduced gradually or suddenly - I just noticed once the hot water wasn't reliable. I've not noticed any change in pressure for the hot water taps.

I've twice had the shower looked at, and then it has worked perfectly for a couple of days, but then the water flow reduces again over a couple of days and then is as bad as ever. The fact the pressure is fine for a while after being looked at makes me think it must be a problem with the shower, but is there any way this pattern could reflect a problem with the boiler?

Thanks for your help!
 
What was done to the shower when it was "looked at"?

It would also help us to know...

What make/model of shower is it (or a photo if you don't know)? Are you in a hard water area? Have you measured the flow rates, e.g. how long to fill a 1 litre jug?
 
What was done to the shower when it was "looked at"?

It would also help us to know...

What make/model of shower is it (or a photo if you don't know)? Are you in a hard water area? Have you measured the flow rates, e.g. how long to fill a 1 litre jug?
Thanks for your reply. I don't know in detail about the what was done to the shower: Once they replaced some part in the thermostatic cartridge (I think), the other time I think they said some part of the cartridge was in the wrong way around. I may not have the terms right, sorry.

The shower valve is listed on the bathroom inventory as "DeLorean Dual Control Concealed Shower Valve". I presume that's the relevant bit? There's also "Typhoon Multi Function Flexi Shower Kit"

I live in Edinburgh, so fairly soft water. Hot and cold taps both take about 6 seconds to fill a 1l jug
 
Can you turn the shower temperature control to its hottest and hold a container/bucket under the shower head for say exactly 30secs, you can then measure the flow rate in LPM.
 
Can you turn the shower temperature control to its hottest and hold a container/bucket under the shower head for say exactly 30secs, you can then measure the flow rate in LPM.
I get 1.5 LPM. Two other points I forgot to mention - the first time the shower was fixed it was because it was getting progressively more difficult to stop it dripping until suddenly, it was on full the whole time. It was fixed, but then the pressure dropped after a few days. The other point - when I push at the lever which turns the shower on (it's on a circular motion), trying to get it go beyond its limit, I get a little more pressure, but it goes down again after a few seconds. My suspicion is it's almost certainly a problem with the shower, but I didn't want to change the shower and then find out it's actually a boiler problem. So I'm wondering if it's worth paying to have someone look at the boiler before changing the shower, or is that just throwing money away, given the problem I've described?
 
1.5 LPM isn't enough to allow the boiler to fire or stay firing, it probably requires a minimum of 2.5/3.0 LPM and is sensed by a flow switch in the boiler. If you get hot water from your hot water tap(s) then shower is the problem.
 
When I come across this scenario 19 out of 20 times it is caused by a blocked filter on the hot inlet to the shower.
 
When I come across this scenario 19 out of 20 times it is caused by a blocked filter on the hot inlet to the shower.
Sorry, a question about this - if this were the problem, would it make sense of why the shower pressure was fine for a day or two after being repaired before dipping down?
 
IMO, more possibly than probably, but filter should obviously be re checked, if you turn the temperature control from fully hot to fully cold, does the flow rate increase while turning it?.
 
If there’s potentially rubbish in the pipes the valve itself (or cartridge, depending on model) should be removed. Then the filters removed and the pipework flushed through thoroughly. Then replace everything- it’s a bit of a pain to do sometimes depending on isolation, so often it doesn’t get done by the less conscientious plumber!!
 
So it appears to be a flow rate problem on the hot to the shower and nowhere else.

So pretty much either blocked filter, incorrect/duff cartridge or a partially closed isolator in the hot pipework to shower.

Process of elimination for these three is what I’d do.
 
So it appears to be a flow rate problem on the hot to the shower and nowhere else.

So pretty much either blocked filter, incorrect/duff cartridge or a partially closed isolator in the hot pipework to shower.

Process of elimination for these three is what I’d do.
Great, thank you
 
So it appears to be a flow rate problem on the hot to the shower and nowhere else.

So pretty much either blocked filter, incorrect/duff cartridge or a partially closed isolator in the hot pipework to shower.

Process of elimination for these three is what I’d do.
Given that it worked OK for a day or two after repair before going back to bad flow rate, do you have an opinion which of these is most likely?
 
Not really!

Unlikely to be a closed valve.

If there was a lot of rubbish and they cleared a filter but didn’t flush the pipes, that fits with your scenario.

Or they chucked the filter away, and now the cartridge is blocked up with rubbish.

Or…or…

Just need to get in there and start trouble shooting.
 

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