Copied from another thread at the request of Tovarishch Sobaka......spasibo bolshoye, Tovarishch, I suppose the enquiry was in the wrong place!
I've just had a new bathroom installed, with the wife's choice of foreign "designer" chrome taps on both the basin and the bath. They look lovely.
But. They only accept 15mm piping, and our old taps were 22mm. So all the piping up to the taps is 22mm, and then the plumber has adapted it to 15mm at the tap connector. Our house is a gravity fed system. The result? A feeble dribble from both hot and cold taps, a particular problem in the bath. These are the sort of things they don't tell you at the showroom..........
My solution sounds radical, but I was intending to do it anyway - fit a combi boiler and get mains pressure everywhere.
Any thoughts?
The only other possible solution I think is to fit a pump for the taps, which I dont' fancy. Or replace the taps with proper ones. Which the wife doesn't fancy. And besides, the bath has already been drilled/cut to accept her fancy schmancy ones. :-(
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I would guess that it is not the 15mm pipe that is the major problem, (unless it is a long length). More likely that the 'foreign' designer taps are specd for mains pressure water ) ie have a very small ceramic disc in them.
A pump will be cheaper than a combi - but make sure that you can comply with the take off requirements from the hot water cylinder otherwise you may be setting yourself up for further problems!
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Ah, that could be it pmh.
>> but make sure that you can
>> comply with the take off requirements from the hot water cylinder otherwise you may be
>> setting yourself up for further problems!
What are take off requirements? I thought that if I install a combi boiler, they'd just rip out and bin my hot water cylinder and cold water tank from the loft?
I'm sure a pump would be cheaper, but getting a combi would put good pressure all through the house - currently hot wat pressure is poor in the kitchen also.
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We had this problem with a new shower. It was a pathetic dribble until we fitted a pump. A couple of years later we upgraded the boiler and went totally mains fed, so the pump was removed and the shower was fine.
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Almost certainly taps designed for high pressure use. Get different taps - and get your plumber to fit them, and don't pay his labour cos he was an idiot.
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>> Almost certainly taps designed for high pressure use. Get different taps - and get your
>> plumber to fit them, and don't pay his labour cos he was an idiot.
>>
The plumber wasn't an idiot. We bought the taps from a showroom, and asked an independent plumber to fit them. We were naive (or uneducated in plumbing matters at best), the showroom people should perhaps have warned us or asked what sort of piping we have, and also perhaps warned us off these taps when we told them we had a gravity system (which we did).
If we get new taps now, it'll be a new bath also, as the one just fitted had to be cut (4 holes) for these taps - getting something else to fit those holes will be near impossible.
I'm not too bothered about paying for a new boiler, our exisiting one is ancient (unknown age exactly) and may well keel over anyway.
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>> I'm not too bothered about paying for a new boiler, our exisiting one is ancient
>> (unknown age exactly) and may well keel over anyway.
>>
If your system is that old then make sure that if you go the combi route that you get all your heating pipework checked out, the sudden increase of pressure in the heating loop from gravity to mains fed can have a nasty habit of finding any weaknesses and the resulting escaping water will be at mains pressure...........
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>> If your system is that old then make sure that if you go the combi
>> route that you get all your heating pipework checked out,
Well, the house was built in 1971 and I imagine it hasn't ever been "replumbed" throughout. The construction is very high quality for the era, and I've no reason (yet!) to suspect that the plumbing is shonky.
I seem to have found a decent and knowledgeable plumber, so I'll check this out with him.
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Aye, we already have a pump to both showers which is brill, but that will be discarded if a combi goes in.
At the moment, we're filling the bath (for the children) from the pumped shower, which isn't ideal but is at least a work around.
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The 'take off requirements' refer to using a pump - IIRC it is to make sure that there is sufficient flow rate available , prevent cavitation, and to prevent sucking air down thro the expansion pipe? It may need a special flange fitting to the hot tank. You will need to look at specific manufacturers installation guide lines.
www.salamanderpumps.co.uk/Download/instructions.pdf
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If you already have a pump you can probably replumb to use it. You do not have the problem of pump capacity if all the taps and shower are in one room. But be careful that if you then decided to feed eg a kitchen sink or utility room that turning other taps on may reduce flow rate or result in un expected high temperature in the shower or bath/sink mixer tap if not thermostatically controlled. Dangerous particularly for children or old people.
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Thanks again, pmh. This is why I keep coming back to replacing the boiler. Solves not just this problem, but improves pressure around the house and is in no a way a compromise, as it would be to use the shower pump.
Using the existing pump would present a signifcant plumbing problem for the bath though, as the bath taps are at one end, fed from behind, and the shower is at the other end of the bath, fed from above, with.
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>> www.salamanderpumps.co.uk/Download/instructions.pdf
They have to do this because they are rubbish pumps.
You dont need fancy take-offs, but you do need to provide a head of water at the pump. In the loft with the feed tank wont cut it
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>>>>They have to do this because they are rubbish pumps.<<<<
I used Salamander site just for a quick example. Do you accept Stuart T as good quality?
www.stuart-turner.co.uk/media/4576-Installation-Monsoon-Universal-4.0-bar-Twin.pdf
Standard practice to take off from body of tank! You can get away with alternative solutions ( I have , on mine), but if you were doing it for a living you would follow the manufacturers guidelines.
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Another vote from me for the taps not being to the correct standard for pressure requirements. Many outlets sell these lovely designs with no mention they will not work properly in a gravity system... particularly upstairs. How do I know... because I was caught out just the same with one of the last bathrooms to be delivered before MFI went bust.
With ours the basin taps are the worse with a minute flow. In truth the easy answer is to change the taps for some proper ones... you may have some claim on the supplier of the original ones??
If you look at some suppliers websites/catalogues they do give min pressure requirements for each tap model. Most of the taps on the B&Q website have a stated min pressure... it can vary by a factor of 5-10x between different taps.
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The last two Iffy Towers had combi boilers as does the present residence and the caravan.
I've always rated them as a good solution.
Why have tanks and heat water you might not use?
Some combis can take a little time to run hot.
I think the hot water flow is adequate, but I imagine it's not as fast as a good gravity system because the combi is having to heat the water as it goes along.
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I wouldnt want to condemn combi boilers on the basis of out of date information. We put a combi into our previous house (so that's about 16 years ago that it went in). If you wanted a bath you had to be patient. Are they any better now, or maybe we just needed a more powerful boiler?
John
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I've had a little look in to it, and apparently a modern 40kw version delivers around 20 litres of hot water a minute and should be able to feed my heating, two showers and a.n.other tap all at the same time, without any ill effect on any of it.
Which seems sufficient to me.
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I have a Myson Midas B, fitted in 1990, its 85000 BTU and will fill the bath with the hot tap alone in about 11mins - even in this weather! - but they`re bound to be better these days i should imagine!
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Glad you mentioned BTUs. What's a BTU as opposed to a kilowatt? Are they both measurements of output?
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1000 BTU/hr is 293W
So 40kW is about 136,000 BTU/hr
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It has little to do with pressure. It is down to flow rates. The combi idea is a no no.
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I have been researching replacing the boiler, (the one that heats the water), and a couple of plumbers have told me to get a combi one size more powerful than recommended for the size of house. This is to maintain an adequate continuous flow of hot water to a shower when the cold water supply is very cold, as it is at the moment.
Last edited by: Old Navy on Fri 17 Dec 10 at 18:59
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...when the cold water supply is very cold, as it is at the moment...
My combi has a winter and summer setting to take account of incoming water temperature.
I still need a fair bit of cold water in a bath, even in this weather.
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But what's flow rate dependent on?
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>>But what's flow rate dependent on?<<
- - - - > :-D
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>> But what's flow rate dependent on?
Flow?? Pressure is useless without water to pressurize.
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True Without water there is nothing to presurise,
Ok what is velocity dependent on.
Last edited by: Zero on Fri 17 Dec 10 at 20:55
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>> True Without water there is nothing to presurise,
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>> Ok what is velocity dependent on.
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The type and amount of powder behind the lead pointy bit.
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Plumbing problem - sherlock47
