Low Water pressure

Hi, can anyone help please, I have just noticed (not been in the house very long) that whenever the shower is on, if any other hot water tap is turned on in the house, the water from the shower stops completely. I knew that combis did this to an extent and reduced the flow but not to stop the flow completely, especially when the shower is right next to the combi and the tap that's turned on after is in the kitchen downstairs.

Could there be a problem somewhere with the combi, the shower or the mains water pressure is there any way of checking what the water pressure into the house is and/or checking anything on the boiler for pressure/diverters etc

For info I have a Mira excel shower and a Vaillant 24KW combi VCWGB

242EH

Any help, comments, pointers greatly appreciated

Thanks Gaffar

Reply to
Gaffar
Loading thread data ...

I am looking to do this shortly and if you do the bit on your land then the water company will most probably do the rest FOC ( severn trent definately do )

Regards Jeff

Reply to
Jeff

Gaffar wrote :-

mains should be min 9 litres/min @ 1 bar iirc

my results of the test you are undertaking are in my post below "new ch system advise reqd" 03/02/2005 fwiw I used a 5 litre container and timed how long to fill

Regards Jeff

Reply to
Jeff

Dave Plowman (News) wrote :-

I believe it increases dynamic pressure, don't think it will affect static pressure

Regards Jeff

Reply to
Jeff

Think flow would be the correct term?

Reply to
Dave Plowman (News)

It's a known fact you don't understand the difference between flow and pressure. Remind us once again of your claimed qualifications? And how much they cost to buy?

Reply to
Dave Plowman (News)

If you have low pressure, such as a poor mains supply, or a combi of the type that automatically throttles down when exceeding its output (thus reducing output pressure), then the closeness of the tap to the combi isn't as important as the height of the tap. Downstairs taps will hog most the flow. The shower may automatically cut out when the pressure drops below a certain figure to avoid scalding/running cold.

Try hard to stop the water coming out of the kitchen tap with your thumb. If it is possible, then the pressure is low.

Christian.

Reply to
Christian McArdle

The pipe bore would not affect the static pressure, i.e., no flow. So, if there's no flow in a system at say 6 bar, the pressure will be the same 6 bar at the end of a 1/4" and a 24" bore pipe.

But (and it is a big but) when there is water flow, the pressure loss due to friction will be greater in a smaller bore pipe. The pressure drops when the water flows.

If you're in a hard water area, the combi heat exchanger may be scaled up. This will reduce the area of the water ways and restrict the flow of hot water throughout the house. Cold should not be affected much.

You could buy a pressure gauge to measure the mains pressure; =A38.50 ish from BES for 0 - 20 bar gauge. They come up on E-bay regularly. 10 bar should be plenty.

Reply to
Aidan

Restricted flow results in lower pressure by volume + ultimately choked pressure to a single tap, a bit like standing on a hosepipe. Wider bore means that at times of heavy demand more water can be sustained at mains pressure to several outlets at the same time.

Greg

Reply to
Greg C

Isn't it easier just to say 'flow'? In practical terms all that really matters is the flow from a tap, and whether this can be maintained as others are used.

Reply to
Dave Plowman (News)

..........that you haven't a clue.

_________________________________________ Usenet Zone Free Binaries Usenet Server More than 120,000 groups Unlimited download

formatting link
to open account

Reply to
Doctor Evil

Tried that today at the kitchen sink and the water sprayed everywhere. I then did the bucket test. HW filled 10 lpm, CW filled 20 lpm, so flow seems ok, the flow from HW tap is more than likely restricted by the boiler which has a output flow of 9.8 lpm. I took your point about the height of the tap and turned on the basin tap in the bathroom and then the bath tap next to it, and again the basin tap just stopped flowing anything. Is it all down to the flow from the combi or could there be something wrong with the plumbing. I am due a BG service about now, is it worth mentioning it to him and getting the boiler checked inside for limescale as someone suggested earlier.

Thanks for the comments

Gaffar

Reply to
Gaffar

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.