now low water pressure in shower

[chicaguapa]

We have just moved into a new house (built 1998). We replaced the leaking shower in the en-suite with a Mira one and noticed immediately that it wasn't as powerful as the Aqualisa one. We've now just had our kitchen replaced and the water pressure in the shower dropped drastically. We spoke to the kitchen fitter who said we needed to run the shower to let the water pressure build up again, which we did and it has improved slightly. But it's still not as good as it was before the kitchen was fitted. Any ideas?

Our cold water tank is in the loft. All our taps still seem to be okay except the hot water tap in the bath which has always been feeble.

 

[chrishutt]

It sounds as if you have a low pressure tank fed hot water system. Many showers are not suitable for such low pressures, so we need to know which Mira shower you have. We also need to know where the cold water for the shower comes from - directly off the mains or fed from the cold water tank.

 

[chicaguapa]

Hi, the shower is a Mira Excel EV. I'm pretty sure the water for the shower comes from the cold water tank. Thanks for your help.

 

[chrishutt]

Mira Excel is suitable for pressures down to 1 metre head. What is the height of the bottom of your cold water feed tank above the shower head?

I suspect you may have partially blocked inlet filters, since performance seems to have declined progressively, especially after kitchen work. The filters on this shower are extra large and shouldn't impair function even if 50% blocked, but worth checking anyway. The shower has a 5 year guarantee, so I think you should get the installer back first and if it looks like shower fault, call Mira.

Another possibility is a partial air lock on the hot water side (since this may have been drained during kitchen work) - does the performance of shower improve much if set to cold?

 

[meldrew's_mate]

Assumption is the system is low pressure tank fed hot and cold to the bath:

As for the bath hot water tap, investigate as for a partial blockage in either the tap body or the approach pipework to the tap. Often bits of cylinder insulation get knocked into the cylinder on installation and find their way to the bath tap, so any reduction in pipe diameter may habour one of these little beasties.

 

[chicaguapa]

Hi, I've just checked and yes the shower does improve when it's set to cold. How might we check if there is an air lock/ sort it out?

Is checking the bath taps something I could do or should I call a plumber in? I've just had one to put RTVs on our radiators so I'm sure he'd come back and have a look at the taps.

I probably haven't made clear that the bath and the shower aren't in the same room (But on the same floor). I don't know if this makes a difference to the diagnosis. Thanks again.

 

[chrishutt]

What is the height of the bottom of your cold water feed tank above the shower head?

If you don't answer our questions we can't progress this.

 

[chicaguapa]

Hi, we have been in the loft to measure how high the cold water tank is. There's a distance of approx 80cm between the bottom of the tank and the shower head. Does this mean it needs moving?

 

[ChrisR]

Well chicaguapa, I guess that means you're a bit blonde?

What you gotta do is what you're told! No point raising the tank if the pipes are blocked now, is there?

Remove shower check filters, and flow from HW side.
Try again.
If doubtful about flow(s), send mains back up the pipe(s) to clear air/blockage.

THEN, raising the tank might be a good option.

 

[chrishutt]

There's a distance of approx 80cm between the bottom of the tank and the shower head

That's a little less than the 1 metre minimum required (although you may just have a metre up to the water level), so it would probably be worth raising the tank by as much as possible.

It may be that the lack of head (pressure) if causing the problem, for example by there not being enough pressure to clear an air lock. But if you lower the shower head to the floor the pressure will be much better and just might clear an airlock.

 

[chicaguapa]

Well I never! Being female (but not blonde) I chose the easiest thing to do first. So I took the shower head off so the hose dropped to the floor, then I let it run on HOT for a minute. And that seems to have done the trick. We reckon the shower's better than it's ever been so it may be that the problem was there after it was installed. It has also sorted out the problem with the hot tap in the bath.

So thanks guys. I'm very appreciative of all your advice and tips. And my husband's pretty impressed I managed to sort it out!