water in shower keeps going hot and cold

lucylucky

whowants2brich wrote: »

Is it a fair assumption that the following are true?

a) any shower which has a brand name on it, no matter what it is, is electric? If it is plumbed into the hot water then it would just be a shower head hanging off the hot and cold water pipes.

b) any electric shower heats the water through the element, as the water passes over them then it gets hot. if there isn't enough water pressure, or too much, the water won't go through at the right speed and consequently the temperature will fluctuate. I wonder if you have something water-thirsty, like a dishwasher or washing machine running, and that this reduces the water pressure sufficiently to affect the temperature and flow speed of the shower. (when the white goods draw water, pressure falls, temp falls... when the white goods are finished, pressure rises, temp rises)

Or am I way off?

Some companies make both electric and non-electric showers. (Mira for example)

If a non electric shower is fed from a combi boiler then it is possible to have fluctuating temperatures if other items, e.g. a washing machine are used at the same time.

petebates26

....or, I could be way off, if it's fed from the hot and cold supply as pinkteapot points out!

whowants2brich

Ah yes, power showers pump the hot and cold through the system. If the water pressure remains constant for both hot and cold, then the pump will know how fast to push both, and the temperature will remain stable. If, however, you use the hot or cold water, the pressure will change and the power shower's pump will have to change to acoommodate. As a result, the constant fluctuation will ensure that the temperature will never be stable, the only question is just how much the temperature will fluctuate.

Our shower isn't even a power shower, but then, our cold water is mains pressure so very fast, so we never use it, we have turned the hot water cylinder thermostat to perfect temp for showering/washing up, and that seems to be fine, without adding any cold to it. This means that the power might fluctuate but the temperature is always constant.

And for what it's worth, I never did understand why people pay to heat the hot water, then add cold water to it because it's too hot. If you can lower the hot water temp by a few degrees so that it's what you can cope with in the shower, you'll probably find that you will get round the issue - and save on the gas bill for heating the water...

poppy_f1

im having the same issue just never got round to sorting it, same its a vokera linera boiler with a miras shower

but i think mine is to do with the boiler cos the water runs hot then cold when im using the bath or the kitchen taps

happy35

Well BG have been out and are going to replace the splitter on the boiler as the heating should stop requesting water when taps are on but ours isn't

allofushere

I know this is an old thread but I ve just fixed my shower thanks to it! My shower was going boiling hot, freezing cold, boiling hot, freezing cold and I thought I would need a new one. But...... Thanks to MSE, a good clean of the shower head, using a needle to clear the spray holes, and VOILA! Good as new! Thank you! :-)

Clairelouise187

Hi there I'm a single girl living on my own and sick of getting ripped off , I had a Gainsborough shower electric feed it broke down and too be honest wasn't happy with the pressure , the cold water belted out but the hot water was very slow and not as good a pressure , after it broke last week I got my brothers friend too fit a new one everyone said the mira sport are fab so I got one ) nôw it's installed the pressure is exactly the same , my brothers friend said its because I live in a row of four houses and the oressurw isn't good but honestly in the house the hot and cold pressure on the taps are fine , I don't have a water tank either ) iv only had it installed a week Snr honestly if I new it was going too be the same I wôuld of ripped the whole thing out . Does anyone know what could be wrong :&(
Regards claire

Clairelouise187

Hi there I'm a single girl living on my own and sick of getting ripped off , I had a Gainsborough shower electric feed it broke down and too be honest wasn't happy with the pressure , the cold water belted out but the hot water was very slow and not as good a pressure , after it broke last week I got my brothers friend too fit a new one everyone said the mira sport are fab so I got one ) nôw it's installed the pressure is exactly the same , my brothers friend said its because I live in a row of four houses and the pressure isn't good but honestly in the house the hot and cold pressure on the taps are fine , I don't have a water tank either ) iv only had it installed a week Snr honestly if I new it was going too be the same I would of ripped the whole thing out . Does anyone know what could be wrong :&(
Regards claire

blogger57

Clairelouise187 wrote: »

the cold water belted out but the hot water was very slow and not as good a pressure , after it broke last week I got my brothers friend too fit a new one everyone said the mira sport are fab so I got one ) nôw it's installed the pressure is exactly the same

Electric showers heat the water instantaneously using electric heating elements. For a given kW (kiloWatt) all electric showers have exactly the same heating effect. I'm assuming you had an 8.5kW shower before. So replacing a Gainsborough 8.5kW with a Mira Sport 8.5kW will not put any extra energy into the water and the flow rate will be very similar. The only way to get a better flow rate with warm water is to replace with a higher kilowatt electric shower eg move up to 10.5kW if you have not already. To do this you may need to upgrade the supply cable from the consumer unit (if it is not 10mm cable) and upgrade the fuse protection (check with an electrician).

Why is cold water from electric shower a better pressure than warm water?
When an electric shower is on a heat setting then the flow rate is reduced to make sure the water temperature is warm enough to shower. In the winter to get a reasonable temperature (say 38 degrees Centigrade) then the shower may only give 3 or 4 litres/minute. If you set it to its cold setting then the flow rate is not limited and you will probably get 7 or 8 litres/minute of very cold water (say 5 degrees Centigrade)!

If the shower did not reduce the flow when heating then you may get 8 litres /minute and a good pressure but it would be quite cold water (say 20 degrees Centigrade) which would certainly not be warm enough for most people.

Hope this explains a little. Does not help you get a more powerful shower from your new one though

lisa701

We have had three different brands of shower over the past 12 years that use hot water from the combi boiler, each one has been rubbish. Lost count of times I've had the boiler / plumbing / shower checked all to no avail. Funny how the stores tell you they are great, but the plumbers I've spoken to have told me they are hit and miss.

Needless to say we ditched it last year and got an electric shower fitted. Best money I've spent!