Water pressure problem to my whole house :(

[cjh2184]

Hi,

I've just moved into a new house. It was a repossesion and all water was switched off. I turned the water on from the toby valve outside so that it's fully open and in line with the pipe. But the pressure is still really bad to both hot and cold water to every tap in the house. There's a gauge in the kitchen showing the water pressure. When there's no taps on it sits at 3 bar pressure. But when any taps turned on it goes down to about quarter of a bar pressure. It can be adjusted by turning a screw on the side of it so that when the taps aren't on it can be put up higher, to 5 - 6 bar which I know is too high. But even with that the water pressure remains the same to all taps when any are turned on. The gauge also goes straight back does to quarter of bar.. Anyone got an idea of what the cause is?

Thanks,

Chris

 

[Puddle]

You have a restriction in the pipework some where,could be the pressure reducing valve or stopcock not opened fully

However first thing to do is for you to reset the p/r valve to what it as before,,,ie 3 to 3.5 bar if not you could cause damage to appliances and fittings and cause a danger to yourself


Call a plumber in as system should e checked if repossession,to get you working correctly and check no other faults that could cause damage

imho

 

[cjh2184]

hi, thanks for the quick reply. The stopcock under my kitchen sink is full open, I can even adjust the pressure reducing valve up to 6, although I have already put it right back to 3 bar. Could the preassure reducing valve be faulty? As although the gauge changes when I turn the screw on top of the PRV, the water pressure remains the same...
My best mates got a friend who's a really good heating engineer, he does a lot of installations. He got my heating system working well, but couldn't seem to work out the cause of the low pressure problem.

 

[justlead1]

Hi As Puddle said a restriction of some kind. I would get a bit of local information regarding water supply. Ask the neighboring houses what there situation is. You may have a galvanised main supply that's choked, or a bit of debris restriction. Good Luck

 

[stevetheplumber]

never heard of a toby valve are you sure its fully open main stopcocks are usually screwdowns rather than quarter turnat least they are in london

 

[Bernie2]

Its simple really. You can have 6 bar pressure on a 2mm pipe but you will not fill a bowl very quick as the flow rate is not high.

You can think of pressure as speed, a mini travelling at 30mph is not the same as a bus travelling at 30mph, yet the speed is the same.

However water mains are usually 15mm-25mm and so it seems obvious that the bigger pipe should give you more flow at 3-6 bar pressure than a 2mm one.

The conclusion is that something is stopping the flow. i.e its got a blockage of some sort. The pressure you seem to be reading is the standing pressure not the dynamic which is the pressure when you have flow. And as you have found out,there can be a big difference.

 

[tackleburger]

Correct! Given the drop from 6 - 0.5 it suggests the restriction is clearly before the PRV. Is there a double check valve after the stopcock if so I'd put money grit being in there after the water being off and on, happened to me a few times.

You are looking for what may appear to you as a straight coupling with a small nut on the side. Turn water off remove and check. If anything is in there turn off at the toby and remove the stopcock chances are you have carp in there too. If you don't have a check valve remove your stopcock and PRV and check internals for grit.

 

[Chrisgy]

chances are you have carp in there too.

Yeah these fish getting into the water mains can be a real problem

 

[Avatar]

1) have the water company done any work recently? (work that might have caused an obstruction/grit to get in the system)

2) Have any components on the system been newly replaced - these could be cause of the problem.

It could be an obstruction, or else a failed componet which seem to be open, but in reality has seized up.

Could be a bit of a pig to sort out. The only thing i can think of to mind is to open the pipework up and fire some off into a bucket (not at 5 bar though!!) You may find this could blast the obstruction clear. The quater turn lever would be my first port of call.

If you was in my area I would come and have a look - I love plumbing 'whodunnits'!!!

 

[Bernie2]

An old trick, was to turn the main off at the outside stop valve. Cut or disconnect it before any internal valves, then clear it as though it was a waste pipe blocked.

Just get some semi stiff wire and make a hoop on the end so that the end does not dig into the walls of the main. And just clear it like a blocked waste, blowing it out every now and then by turning the outside stop valve on occasionally and catching the water in a bucket.

The thing is, I suppose for a main to be blocked like that is a bit unusual now days as they are mostly plastic or if you prefer MDPE. It was sometimes met with in the lead main days.

Perhaps though it might be a crushed supply pipe if its not the water supplier. Any signs of recent building or ground movement round about?

Could of course be gravel in main or one of many things.

Its a case of just looking and guessing. Perhaps just think of how you would block a pipe yourself or reduce pressure and flow, then look if somebody has done that.