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New flat - new boiler, advice needed

(32 Posts)
tostaky Wed 30-Jan-13 21:49:10

We are in London, 1st and 2nd floor flat (conversion).
Low pressure as in when kids are running the bath, there's no hot water in the kitchen.
We are re-doing everything in the flat (very old and dated).
The plumber who works with the builder recommends a pump (to get better pressure) and a boiler with a tank integrated.
One bathroom, one shower room, two toilets, 2 adults and 3 small kids.

Ive read in a magasine that a boiler with an integrated tank was for big houses. A boiler with a tank on the side for a medium + size of household and a standard combi boiler for "normal household" ie 2 adults, 2 kids one bath one toilet.

What size is your family?
How many bathroom/showers/toilets do you have
Whittle of boiler do you have
What make is it?
Are you happy.
If you have a pump on the main, how noisy it is, what make is it and are you happy with it?

Thank you!!!!

nocake Wed 30-Jan-13 22:53:57

Two adults, one toddler.
One shower, one bath (both in the bathroom), two toilets.
No. I'd never fit a combi in anything other than a small flat. I used to have a conventional boiler with a hot water tank and it was much better.
You're not allowed to put a pump on the mains. You can only pump from a storage tank (hot or cold).

Ponders Wed 30-Jan-13 23:08:09

we are all adults now, number in residence varies from 2-7

3-storey 3-4 bed terraced house, 1 bathroom & 1 shower room, both with loo

have "standard" combi boiler which is absolutely fine even with max occupancy (what I love & have always loved about combi boilers is as much hot water as you need when you need it!)

granted if all taps are trying to run at once, & both loos happen to have been flushed too, water slows briefly to a tiny trickle, upstairs and down - otherwise water supply is perfectly adequate. (Mains pressure here is excellent)

Ponders Wed 30-Jan-13 23:10:54

oh, boiler is Worcester, missed out that bit

28i junior

it says for 'apartments and small to medium sized properties with 1 bathroom' but we're v happy with it with a somewhat larger property

PigletJohn Thu 31-Jan-13 00:20:36


you are not allowed to put a pump on the mains supply, only on your own water storage tank

have you currently got a hot water cylinder? What colour is it?

have you currently got a cold water storage tank, in the loft or on top of the cylinder?

have you currently got a combi boiler?

Please fill a bucket at the kitchen cold tap, time it, calculate how many litres per minute you get. this is very important.

what colour is the incoming water main? blue plastic, black plastic, copper, lead or iron?

have you got your own stop cock or water meter in the pavement, or is it shared with other flats?

tostaky Thu 31-Jan-13 15:31:32


Plumber and builder assure me that we can put a pump where the main starts...

Piglet - at the mo we have a biaci combi boiler, no water tank or cylinder. We are doing up the flat so everything will be replaced.
it takes 9.5 sec to get one litre of water so that makes 6.3 liter per minute
we have a stopcock in our flat
so what do you think??

tostaky Thu 31-Jan-13 15:54:31

regarding the pressure... other people in my street have got good pressure... ill need to ask the downstairs flat too.
and pressure is ok except in the kitchen when someone is also using the bath (sink in bathroom ok and toilet ok)...
so maybe it is just a plumbing problm and we dont need a pump after all?

should i just call in another plumber for some "consulting"? and pay him for an hour of work?

ISeeSmallPeople Thu 31-Jan-13 15:57:33

Message withdrawn at poster's request.

PigletJohn Thu 31-Jan-13 16:03:21

6.3 litres per minute is nowhere near enough for a combi. It will give a poor shower and will take (100/6.3) fifteen minutes to run a bath. 12 lpm is generally considered the minimum acceptable. Measure it at the cold bath tap just in case it is your kitchen tap that is causing the trouble.

I'm shocked that your plumber told you he can use a pump to suck water out of the incoming main. Ask your water company if it is allowed (it isn't).

Having a stopcock in your flat doesn't show if you have an individual or a shared supply into the building. If it is shared, your incoming flow will drop when other flats are drawing water.

Good idea to look for a competent plumber for advice. Ask around friends and neighbours to see who they recommend.

PigletJohn Thu 31-Jan-13 16:04:07

is this of interest?

PigletJohn Thu 31-Jan-13 16:10:26


A megaflo is great, but it can't create extra flow or pressure; it is limited by what comes into your home through the incoming watermain. Tostaky appears to have poor flow, very likely due to an old, undersized waterpipe. If she had a house or a ground floor flat, it would be easier to dig up the front garden and lay a new, larger, pipe. We don't know about the old pipe yet.

tostaky Fri 01-Feb-13 08:33:42

in the bathroom i get 12.5 l/m
so there is a problem with my kitchen tap?
but there must be another problem with the plumbing which means that when i run a bath, the pressure drops in the kitchen.
that has nothing to do with the pressure on the main? am i right? and in that case we dont need to have a pump? (lets assume it is legal)because presumably, with all the plumbing being updated, the pressure problem and the kitchen tap problem are likely to be resolved?
tell me if im wrong.

ill call a decent plumber i know for some consulting. should i pay him an hour of work (ie £60, the standard rate)? or more?

tostaky Fri 01-Feb-13 08:35:40

just to add we cant dig the front garden, the pipe comes from the basement of the downsatirs flat and lets just say that we are not on very good terms with the other landlord (who lives in greece, the tenants are ok). so not an option to change the size of that pipe.

PigletJohn Fri 01-Feb-13 10:49:55

I expect your kitchen tap is a flashy stylish Italian design with ceramic discs, perhaps a joystick, and tiny little tails the size of pencils. If you get a UK-made tap designed for our lower pressures, it will have larger internal waterways and larger connections, and will give better flow. Single-hole taps are more cramped so have less room for the water to get through. The greatest flow comes from a UK Pillar or Bib bath-tap which has large connections, large waterways, and large flow.

Flexible tap connector hoses, and ball-o-fix service valves, also contrict water flow, unless you make a point of buying large-bore ones.

I expected it to be difficult for you to lay a new pipe, but look out for any plumbing work done for the downstairs flat and see if you can get yours done at the same time. It would be interesting to know what your incoming water main is made of, and if you have your own meter or stop-cock in the pavement outside.

Even if you decide you want to put a pump on the incoming main, it is not allowed.

If you can find a more competent plumber, why not ask him to propose, and actually do the work? better than having a known incompetent plumber do it. Any plumber who tells you to put a pump on the mains supply is incompetent.

The bathroom/kitchen contention is because you have a limited amount of water coming into your home. If you open one tap, all of that water can come through that one tap. If you open two or more taps, or flush a WC, or your washing machine is taking in water, then that limited amount of water is shared out between all the taps. If you have no cold water storage tank, then the mains supply has to be shared between all the hot taps and all the cold taps. If you have 12lpm coming into your house from the main, you can have 12lpm coming out of the hot bath tap, or 6lpm each coming out of the hot and the cold bath taps, or 3lpm each coming out of the hot and cold bath taps and the hot and cold sink taps, or 2lpm each coming out of the hot and cold bath taps, the hot and cold sink taps, and the hot and cold basin taps (actual amounts at each tap will vary depending on pipes and taps, but the total amount will not vary).

This is a very common problem for people who convert to a combi with no storage, and do not have a large incoming water pipe. A combi with poor incoming water flow is OK for a single person with one bathroom. It is increasingly unsuitable for homes with more than one bathroonm and more than one occupant.

ISeeSmallPeople Fri 01-Feb-13 11:05:50

Message withdrawn at poster's request.

tostaky Fri 01-Feb-13 14:36:54

lol our current kitchen is at least 10-15 years old and its ikea. i suspect the sink is from ikea too...
so if i cant have a pump and if i cant dig the garden then what can i do about the pressure?
would a combi with a tank be the solution?

tostaky Fri 01-Feb-13 14:38:58

the pipe where the stop cock is in copper? (dark gold colour)

Deux Fri 01-Feb-13 17:43:08

When you are talking about pressure, are you meaning flow?

Do you have space to fit a storage tank somewhere? You could pump your stored water and so increase the flow. Might be your best option for now.

Are you sure that your plumber is suggesting a pump on the mains and isn't meaning a pump for the storage tank?

tostaky Fri 01-Feb-13 21:38:53

Yes he definitely means. Pump on the mains... Apparently it is a new pump that is legal and everybody is buying it....

Yes we could hide a storage tank in the loft.

And yes I mean flow....

Didn't get round to call a plumber today....

PigletJohn Fri 01-Feb-13 22:01:00

"legal and everybody is buying it.... "

Nope hmm

Email your water company and see what they say

We could sketch a system for you with a hot water cylinder, and a cold-water tank in the loft, and a shower pump (you would not need a pump to fill the bath or sink). Very simple, traditional and reliable.

the cylinder can be heated by a conventional boiler; or by a system boiler; or by solar plus a boiler; or by a combi (all heating engineers except complete beginners know how to heat a cylinder with a combi)

IMO you will not be happy with the flow when several taps are run at the same time, unless you have a cold water storage in the loft, and you do not appear to have scope to improve the flow by running a new, larger, water supply pipe.

A side benefit is that you can put one or two immersion heaters in the cylinder, so you will have hot water even when the boiler is out of action.

Once you have seen your water company's reply, I think you will re-assess your plumber.

PigletJohn Fri 01-Feb-13 22:24:34

OOI I just checked The Water Supply (Water Fittings) Regulations 1999

Looking at Regulation 5, if he wants to install a pump drawing more than 12 litres per minute from the supply (and you say you already get 12.5 at the bathroom) he has to inform the water company in advance and obtain their permission, and by regulation 6 has to issue a certificate on completion to you and to them stating if it complies with the regulations. Otherwise, see regulation 7.1 (but 7.2 and 8 might apply to you)

It is my understanding that permission is not normally given, but I must concede that it might be possible, but I should be very interested to see the terms of the approval.

tostaky Fri 01-Feb-13 22:31:33

So why a pump for the shower? We have enough pressure as it is now to have a shower.
What would suit us best between conventional boiler/combi or system boiler? Where do i find info to make an informed choice?

Thnk you

Ps: I've never been too keen on the pump because of the likely noise also because I don't want to create trouble to my neighbour...

tostaky Fri 01-Feb-13 22:33:23

Piglet - I doubt he would have ask for permission!!

tostaky Fri 01-Feb-13 22:37:54

And what about those positive and negative pump you can fit on your boiler/water tank?
If we use them, would we still need a pump in the shower (which I really want to avoid!!!!)

PigletJohn Fri 01-Feb-13 23:21:16

you can put a pump on water from a tank if you wish, and it can give a more forceful shower.

However if you have a combi and a tank, you can use the combi, with no pump, for your showers, and the tank (also with no pump) for your baths, and they need not be in severe contention for the water supply; you will be able to run a (tank) bath at the same time as having a (combi) shower. A bath needs good flow, but not much pressure.

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