Buying a house: water pressure / shower questions

savageHK

Hello all.
First post in this section. We are looking at a particular house we have spotted and are seriously considering putting in an offer. However, we would need to redo the main bathroom; and the shower room in the loft conversion is a bit strange.

Our understanding of the property is that it had the loft conversion done c. 15 years ago. This gave a bedroom, shower room and loo. The boiler (a fairly new Potterton Promax Combi HE plus 28kW, if I wrote it all down correctly) is in the loft conversion [Is this a good brand??]. The shower room right next door to said boiler has an electric shower rather than being plumbed direct to the boiler (and there is only cold water to the tap; there is a heating element for the hot water in the sink).

Can anyone think of why the shower wouldn't be plumbed direct to the combi boiler (I'm hazarding that 15 years back combi boilers couldn't handle a shower??).

The shower water pressure seemed a bit low. I like a good pressure shower! If I understand things right; there are two things to worry about here for a 'good shower': how much water is getting to the shower head (flow rate) and then how many holes you shove it through (the 'pressure' you feel when you shower). Is it possible to have a good flow rate electric shower (i.e the one that's there is just not fully up to scratch?)? Or given the boiler, would it be better to plumb it to that?

The bathroom (directly under the shower room and almost directly under the boiler) has no shower proper just a bath with one of those taps which is either a bath or a shower - that appears to be plumbed to the boiler but "shower" pressure there was equally dire if not worse. If this was plumbed as a proper shower should this improve? We would likely remodel this entire bathroom in any case.

We have asked for (and been provided with) details of the builder who has worked on this property for many years but have not yet called. Any advice on further questions to ask him would be most welcome... It is unlikely that there is space in the loft to put any sort of tank for water storage.

I see that United Utilities quotes that pressure to any house will be "a minimum of seven metres static head" - what on earth does this mean?

Thanks!

katz03

Hi - I'm not technical - and sure someone will be along to answer your questions soon, but when we re did our bathroom a few years ago I wanted a power shower - we didn't have the water pressure required (old property - inlet pipe size - all over my head lol) But our plumber recommended a pump to increase the pressure and its been great.

savageHK

Thanks Katz; do you know how big the pump is and where it lives?

Myser

Have a look at this link to give you an idea of the cost and sizes of shower pumps:

http://www.plumbworld.co.uk/shower-pumps-58-0000

Whether you need a shower pump or not and what size you need will depend on the type of plumbing/central heating installation that you have.

If you do need one, expect to pay between £100-£300 for a decent pump. The higher priced ones can work with more showers and have a better flow rate.

hotcookie101

You can't use a pump with a combi boiler, they can only be used with a hot water tank (as far as I know)
Our shower is directly off the combi and we have great water pressure (high flow rate) but we specifically got a combi with a really high flow rate as we like our showers (ours is vailiant 937 I think, boiler people said we only needed the lower one, but the flow rate was too low)
You probably wouldn't be able to run 2 showers off the combi at thee same time

keystone

savagehoutkop wrote: »

] The shower room right next door to said boiler has an electric shower rather than being plumbed direct to the boiler (and there is only cold water to the tap; there is a heating element for the hot water in the sink).

Can anyone think of why the shower wouldn't be plumbed direct to the combi boiler

Yes its quite simple - when the loft conversion was done the house boiler was in a different location. Its only when the boiler was replaced later that they happened to put it in the roof.

The shower water pressure seemed a bit low. I like a good pressure shower! If I understand things right; there are two things to worry about here for a 'good shower': how much water is getting to the shower head (flow rate) and then how many holes you shove it through (the 'pressure' you feel when you shower). Is it possible to have a good flow rate electric shower (i.e the one that's there is just not fully up to scratch?)? Or given the boiler, would it be better to plumb it to that?

The pressure at the electric shower will be virtually the same as at the boiler. There is no benefit, in terms of pressure to ditching the electric shower, replacing it with a thermostatic one and replumbing up there apart from getting hot water at the basin. Actually it would be better to keep it separate.

If this was plumbed as a proper shower should this improve?

I do not understand what you mean.

I see that United Utilities quotes that pressure to any house will be "a minimum of seven metres static head" - what on earth does this mean?

It means a minimum of 0.7 bar at the first floor of the building.

Cheers

keystone

savagehoutkop wrote: »

Thanks Katz; do you know how big the pump is and where it lives?

Yours is a mains system. As it stands you cannot have a shower pump as you may not pump mains.

Cheers

Jaynne

Electric shower performance also depends on the power of the shower not just the water pressure. For a powerful shower I think you'll be wanting something with 10kW or greater power at least going by my experience. Of course if the water only dribbles out the tap that's not going to be the problem.

savageHK

keystone wrote: »

I do not understand what you mean.

Sorry, not too clear! The main bathroom doesn't have a shower, it has a bath with one of those taps which either fill the bath, or if you pull up a knob on the tap, it comes out the shower head instead.

keystone

Ah I see you'll have a standard bath shower mixer (BSM) then by all accounts. For use with a combi boiler you would really need a thermostatic shower either as a direct replacement for your BSM (like the MIRA Excel) or a separately plumbed one.

Whatever you have your performance will be limited by the specifications of the boiler (a certain number of litres per minute on DHW at 35 degrees C rise) so don't go hoping for a rain shower or one of those fancy multijet things as you'll be wasting your dosh. For a separately plumbed one obviously you want to plan for doing the minimum of damage to walls, tiling etc for pipework.

HTH

Cheers

unclebulgaria

The first thing you have to do is get the pressure tested at the roof level and floor level, any pressure you have quoted by your utilities co. will only be to your mains stop !!!! (the one in your house).
Its a mistake to think that higher KW increases your shower pressure, this just allows a house with a good incoming pressure to have a shower that will run harder/faster.
Its always wise before you increase a showers KW to get a qualified electrician in to check the supply cable to your current shower as 10kw showers shouldn't be run off smaller than 10mm cabling. You will also have to have your consumer box (the box with your fuses in) checked to see if there is enough room for a greater kilowattage.
What you also have to remember is the higher you go the less pressure you will have regardless of your incoming pressure, you have bends, kinks, elbows to contend with that all create friction in the water pipe.
A combi will run a thermostatic shower easily if you supply it with enough pressure but, it cant perform miracles.
Get a decent local GSR plumber/heating guy in and make sure you've checked him out with references before he starts work, ask him to check everything over and offer to pay him as a quick look might not be enough. Be wary of plumbers/heating guys put forward by builders unless he can provide good refs. They are usually buddies who will pass on work regardless.
If I were you I wouldn't rely on my combi for everything as its failure means you'll be stuck for a shower, keep one electric shower then you cover yourself in the event of a breakdown.
There is a way of increasing the flow to an electric shower but it involves fitting a break tank that fills up from the mains rather like a cold water storage tank would have done before your combi was fitted, it needs to be large so not to run dry during operation and involves fitting a water pump but, these pumps are not really to be fitted into a loft (which you haven't got). Remember pumps are designed to push water and not pull it. Too detailed to describe here but have a look around for more info.
Last but not least, get your water standing pressure and working pressure checked to make sure that combi was fitted correctly in the first place!