Insufficient pressure for shower - any remedy?

[Sam Gangee]

We had a Triton T80i shower unit fitted in the en-suite bathroom a few years ago. It has always given problems and is a real pain as the water temperature and pressure fluctuates continually. If someone flushes a toilet or turns on a tap, the darn thing just turns its heater off and spurts cold water. The Pressure switch appears to have no usefuyl effect whatsoever. In fact I've never managed to get hot water out with the Pressure set to "low" - the opposite to what I'd expect.

I assume this is a "normal" result of the mains water pressure upstairs being too low. The plumber (having been paid as part of a house extension contract) says there's nothing he can do. I find this hard to believe. My guess is that it could be improved by fitting a larger diameter pipe from the incoming mains supply and/or fitting a different shower - maybe with a header tank (although the roof isn't very high).

Suggestions welcomed.

Martin (South Cheshire)

 

[ollski]

just remind me what sort of shower it is..electric, pumped or power shower, most triton showers seem to be called a t80!

 

[MANDATE]

If it is affected by the toilet flushing I guess it must be electric.
Mine goes to 'very hot' when toilet is flushed because it slows down the flow rate and I assume the pressure switch prevents this by switching the electric to the elements off.(better then being scalded)
I understand all electric showers cater for 15mm pipe work and increasing the size of the supply pipe up to the shower will not cure your problem.
The smallest size shower is about 7kw and is only just about up to the job, don't forget the temperture rise is limited and you are starting with very cold water in winter time.
Obviously the bigger the kw the better but you may need to fit a bigger cable.
There is usually two heating elements and it could be one of these has failed. Other than that you slow the flow rate down with the knob provided which allows the water to reach a higher temperture,but the downside is the water just trickles out of the showerhead.
You cannot use a header tank with an electric shower, the pressure would be a lot less and if it was more you could not fill the header tank at a fast enough rate.
If there too many holes in the showerhead it allows water out at too fast a rate for the water to achieve the desired temperture.
hope all this makes sense

 

[Sam Gangee]

It has water and electricity feeds. I guess this makes it electric?

http://www.muswell-hill.com/foxandco/pages/electricshower.htm

Switching it to low power reduces the water flow but doesn't stop it from switching the heat off. In fact I can't get it to switch the heat on if I start on low pressure. It has to be on high before the neon will light and the water becomes warm.

If a heater has failed, it must have failed in the box because it's been like this from new.

I take the point about winter - the water doesn't get as hot - but it still switches the heat off if a toilet is flushed in summer.

The main problem is not toilets but the washing machine.

But even with nothing else taking water in the house, the shower pressure still fluctuates.

 

[Registered Gas Man]

This is low water pressure pal. A problem with some electric showers regardless of make! What you need is a cold storage tank in the loft which will then supply the shower, then you can pump the water and get a constant pressure . Check if this will work with your current shower!!

Unfortunately you cant pump directly off the mains:

A] The seals on any pump will not take pressures of around 7bar that the mains can get up too

B]Its against water bylaws as pumping water directly off the mains can rob your neighbours water source (so they say)

you could not fill the header tank at a fast enough rate.

Not sure about this comment as if the header tank held enough to supply an average shower why would it run out of water??!!

 

[Sam Gangee]

The shower unit is about a foot below the bedroom ceiling. The loft space is small - not high enough to stand in. Maybe 5 feet at the apex, giving at best about 3 feet of "head". Would that be enough? If so, what capacity tank would I need? I assume the pressure increases with the volume of water? Or is it just the depth of water that determines the pressure? I'm useless at maths!

 

[MANDATE]

It could even be a neighbour using water that causes your shower to drop its pressure and I don't think there is any simple cure. At least the pressure switch seems to do what is intended bypreventing you from being scalded.
I believe you can only use a electric shower in conjunction with the mains supply so using a header tank is not an option. Not only that a electric shower would not function on a 3 foot head of water.
To stop fluctuation you have to avoid the mains supply which means avoiding electric showers.
You can have both hot and cold water at the same constant pressure if they come from the same source of pressure (ie via water tank) but you may find a 3 ft head inadequate, in which case you would need to install a pair of pumps.
I don't think there is a 'electrical heated/ power shower' available.
Pressure is determined by the head of water not the volume and I have an electric shower because my tank is in the airing cupboard giving a head of about 12 inches

 

[MANDATE]

Mains pressure at 3 bar equates to 43 pds per sq in or 100 ft head.
3ft head equates to 1.3 pds per sq in or 0.089 bar.

 

[MANDATE]

Sam,
Have a look at the posting by mukit Fri May 09 2003 'low water pressure for shower'

 

[MANDATE]

Just to let you know MIRA appear to have a electric shower that uses low pressure water from a tank that incorporates a pump. MIRA ELITE 2 £227.

 

[Sam Gangee]

Ah, cool, (or hopefully "hot")!

Thanks for all the replies.

I suspect planning permission will not be granted for a 100 foot water tower so I'll investigate the other options.

This looks like it:

http://www.discountedheating.co.uk/shop/acatalog/Mira_Elite_2.html

 

[ChrisR]

Yep they work OK. Not exciting at all, but they work.
Check the size of your cold water tank in the loft though, some of them are tiny in new build.