vroomtshh

I'm in the middle of planning my bathroom installation. Currently I have 2 22mm pipes going to the bath taps, which then have a T with a 15mm pipe coming out to go to the shower. Shower works directly off the combi boiler. The taps have flexi hoses.

At the moment, the shower has decent pressure, but the bath takes an age to fill up. I assume this is more to do with flow than pressure, but I do know that this is a low pressure area. My question is - what size pipes should I use in my new installation. I already plan to remove the flexi pipes as they are an obstruction to the flow, but should I use 22mm to the tap and 15mm to the shower as is, or some other combo?

Pipework will be copper pipe with solder fittings

dojj

iTrader: (3)

it should be as it is already

the 22mm will allow more water into the bath to fill it up faster

are you sure the taps in the bath are actuallt 22mm taps for teh bath rather than 15mm taps for the sink like osme peole will flog oyu?

vroomtshh

No Idea. They do look the same as the sink ones. But the new ones are definitely bath taps. So hopefully with them, and with no flexi join, it'll fill up a bit faster.

TIFF

Running 22mm pipes to the bath will make LOOK like it is filling slower, as it hasnt got as much pressure behind it, unlike with 15mm....

Most tank feed hot baths are 15mm Cold main and 22mm Hot.....where as if i do a combi, i usually run both 15mm to the hot and the cold, as then the hot water bollocks out and the client is pleased as punch

vroomtshh

Mines fils from a combi. But from what you;re saying, and basic physics principles, that by putting on a smaller tap it'll creat more pressure and look like more is coming out, but my bath wont fill any quicker? That makes sense.

But, and correct me if I'm worng, I cant alter pressure, but can alter flow? What I want is the water to flow as much as poss. At the moment it takes 15mins to fill a bath. Maybe thats not over average. It just seems like ages

Christian and Beccy

iTrader: (14)

Our bathroom has 22mm pipes to the bath, then 15mm off to the basin and the shower is separate 15mm pipes.

We have a VERY powerful Valliant Combi and it takes absolutely AGES for hot water to come through, I'm guessing that this is because of the volume of water in the 22mm pipes? The bath does fill fast though once you have hot water through. It's a 1900x800 bath and it fills in about 10 mins.

vroomtshh

I have the exact opposit of that. I have almost instantaneous hot water. The boiler is abot 5m away max, and is way more than the house needs as I'm planning on extending. But the actual water flow is slow. My bath 1700 x 800 and takes well over 15mins. In fact I think I'll time it tonight.

While we're talking of bathrooms, and I remember your glass topped bath - I am looking to install a granite windowsill/worksurface and wondered if you had any idea where to source such a thing? I had considered a headstone maker, but cant really think where else would do that kinda thing

dojj

iTrader: (3)

kitchen people will soruce you the granite you want

it's not just specific for the kitchen enviroment as i know a guy who's just sold up his granite company and he was getting stuff made up for all sorts of applications

rssteve

your combi is probably flowing as much as it can heat, does the cold tap fill quikcer than the hot or are they equal? if the cold flows more then i would say you either need a bigger boiler to allow more flow. if there equal then it must just be down to bad flow.

TIFF

The hotter you have the water set on a combi....the SLOWER it will flow through the system. As to get the water hotter, it needs to stay in the waterways of the heat exchanger for longer.......thus making a slower flow.....

You can have it flow Slowly so the water is VERY hot.....or.....flow at a fair rate, but not as hot.

Turboboy67

Combis should have 15mm hot and cold pipes run to all taps, due to pressure and heat loss.

Also if you insulate the hot pipes as much as possible, this will also help

THE RADMAN

iTrader: (2)

bin the flexys for a start, theyre prob reducing the bore down to 10mm, theyre a pain, diy bodge

rocky_robin

Have youu checked the pressure coming into the house?
Ideal would be 20l/min.

As Radman stated the flexys have got a tiny bore compared to the solid metal.

Also, is there a filter within the tap? If so, take it out and clean it. You'd be amazed the difference it will make.

vroomtshh

Hot tap flows same as cold tap. The flexi pipes are gone as soon as the new suite goes in. And a new tap wont have a blocked filter. Will try this and see how it goes

vroomtshh

Oh and how would I check the pressure coming into the house?

rst-s2

Sounds like the pipework from the old tank fed system before combi was installed is still in 22mm around the house and has not been changed for 15mm which would work alot better with combi system... as for getting hot water quicker at bath the 22mm feeds on a combi system not helping and possibly changing these to 15mm would be better if not the only other solution is to install a pumped secondary hot water which is only really installed in big houses with basins and baths etc far away from boiler to resolve the dead leg of cold water draw off..... worth thinking about tho

can check the pressure of mains by getting a pressure gauge to screw on to a outside tap can get them from screwfix for about Ł10

foreigneRS

whoever did the plumbing in my house was a genius - there is a 15mm cold supply to the house that goes to the combi boiler but the outlet from the boiler is 22mm. what the hell is the point of that?

dojj

iTrader: (3)

i think i can still out genius your plumbing genius:

when they plumbed in our boiler, direct from the mains, they didn't connect anything to the cold water, so every tap let out hot water, even the toilet was flushing hot

and one of the guys who's just bought a new build flat round the corner has had the same problem, so they are having to dig out all the pipework and try and find out what's gone wrong

on the other hand, all our pipework for the heating is 22mm, not too sure about the taps though as the boiler is right below the bathroom and in the kitchen so water comes out from the 22mm pipes int he bath at a good rate of knots