Water mains pressure increase

[Ahmiccc]

Hi All,

 

looking for some advice on how to get higher pressure from water mains.

 

I’ll start off with from the beginning and they came round first to test my water pressure and flow and said my pressure is fine but he had to do my flow rate on the garden tap which was the very old fashioned hose of an ID of about 8mm and wasn’t really getting the right flow but he said that’s normal for this pipe, he couldn’t come in then due to covid, I asked him how to increase the pressure he mentioned a few things and one of them was lay a new bigger water mains from main pipe to my house so this is all done old pipe is 15mm copper and new one now is 32mm mdpe, this has since been inspected and filled in and connected and the people connecting it were shocking didn’t have tools borrowing our tools, not prepared for the job late, unwilling to do a proper job not having right connection equipment either just shocking anyway it got connected and I had 2.1bar which I was expecting more as I had also placed a pressure regulator in my line to reduce from an expected 6bar or whatever. After some testing my self with and without the PRV, on different taps with pressure gauges all I could get is 2.1 bar and when one tap was opened I’d get 0.75bar maximum but mainly sitting on 0.5bar and sometimes going up to 0.75bar.

 

After speaking to Severn Trent they said maximum pressure in the line is 2.1bar which isn’t great but I guess I can’t do much about apart from continuously complain so they raise the pressure hopefully, another thing they said it shouldn’t drop below 1.5bar and when I mentioned to them that mine was when running he said he would have to raise to his manager.

 

So what I’m essentially preparing for is worst case they can’t give me more pressure than 2.1 bar and and can’t help, so what I’m asking what are my options? to have in my house ive been looking at booster pumps possibly a grundfos scala 2 maybe a breaker tank in between mains and pump just more of an idea of what to do and how to implement.

 

It’s a 90m2 , 3 bed house with 2 bathrooms, and scope with more extensions and maybe an en-suite. 300m2 garden where a long hose is needed for water probably sprinkler attached to it

[JohnMo]

Why do you need more than 2.1 bar?  Is there something driving this need, or do want more flow?

 

What is current plumbing set up for hot and cold water, is it a mains pressurised system or fed from tanks in the loft?

[Conor]

First, there is static head (pressure). You've measured this as 2.1bar. Then there is dynamic head, which is how water pressure drops as flow rate (and therefore friction) increases. The biggest factor in this is pipe diameter, roughness and any other physical restrictions in your pipe,

 

The mains pressure will never increase. It's in the water companies interest to keep pressure as low as possible to reduce leakage. They'll have a zone where pressure is managed, and they'll manage the pressure so the highest elevation properties get at least 1.5bar at the customer connection point. They usually set PRVs to deliver 2bar at these points. In your case, the water company is meeting their statutory obligations and are unlikely to do anything more. Only suggestion I have is that you request they fit a pressure logger at or close to your property to see what the minimum pressure is. Their models might be slightly off and if the min pressure on the main drops below 1.5bar, they are obliged to take action. Keep on them.

 

As for things you can do, get rid of you PRV to start off with. You'll either need to install a booster pump or replace all of your key pipes with larger diameter ones.

[Ahmiccc]

1 hour ago, JohnMo said:

Why do you need more than 2.1 bar?  Is there something driving this need, or do want more flow?

 

What is current plumbing set up for hot and cold water, is it a mains pressurised system or fed from tanks in the loft?

After one tap is open I have no pressure of hot water so I can only imagine going forward when I have two showers and maybe sink or utility sink tap open no pressure in the showers and stuff

 

Cold water comes in on ground level is a mains pressurised system at 2.1bar and the boiler is in attic currently fed by 15mm pipe

[Ahmiccc]

2 hours ago, Conor said:

First, there is static head (pressure). You've measured this as 2.1bar. Then there is dynamic head, which is how water pressure drops as flow rate (and therefore friction) increases. The biggest factor in this is pipe diameter, roughness and any other physical restrictions in your pipe,

 

The mains pressure will never increase. It's in the water companies interest to keep pressure as low as possible to reduce leakage. They'll have a zone where pressure is managed, and they'll manage the pressure so the highest elevation properties get at least 1.5bar at the customer connection point. They usually set PRVs to deliver 2bar at these points. In your case, the water company is meeting their statutory obligations and are unlikely to do anything more. Only suggestion I have is that you request they fit a pressure logger at or close to your property to see what the minimum pressure is. Their models might be slightly off and if the min pressure on the main drops below 1.5bar, they are obliged to take action. Keep on them.

 

As for things you can do, get rid of you PRV to start off with. You'll either need to install a booster pump or replace all of your key pipes with larger diameter ones.

I’ve lost all hope in Severn Trent honestly, so maybe look myself to fit this pressure logger, or would that not be valid to Severn Trent ?

 

should my mains pressure drop below 1.5bar when one cold water tap is open ?

 

yeah I’ll get rid of the PRV, don’t need it with 2.1bar, can I install a grundfos scala 2 straight into the water mains and will it work essentially cause from my understanding a pump can only deliver what it’s given only way to increase is maybe having to install a cold water storage tank in attic (no space anywhere else) then the pump from there to rest of the house.

[Marvin]

42 minutes ago, Ahmiccc said:

 

 

yeah I’ll get rid of the PRV, don’t need it with 2.1bar, can I install a grundfos scala 2 straight into the water mains and will it work essentially cause from my understanding a pump can only deliver what it’s given only way to increase is maybe having to install a cold water storage tank in attic (no space anywhere else) then the pump from there to rest of the house.

 

Hang on!!

 

Perhaps you should think about putting the PRV AFTER the pump as suggested in the manual: unless your happy for your pipework to handle 6bar?

[Marvin]

@Ahmiccc My understanding of your problem is a bit like a foot pump used to blow up a car tyre: It will achieve the pressure but not all in one go!  So like the foot pump the mains water will supply over time and the pump would slowly build up pressure.  However when you let go of the pressure by opening a tap it will slowly drop.

 

I think the pressure is fine at 2 Bar its the rate the water is flowing along the pipe (just like a small foot pump for a car tyre) 

 

In order to over come this in my humble opinion I would recommend a storage tank.  The real test is the flow rate. Go to the fastest running tap with a bucket run the tap whilst timing, until full. measure the contents and  divide the result by the minutes it took to fill this will tell you HOW FAST the water is in litres per minute. A typical shower needs between 12 and 16 litres per minute. Compare the result. 

 

If you put the big pump on the mains, sure it will suck the water but only to a maximum of one bar negative pressure otherwise a vacuum will form in the pipe.

 

I hope this helps. Sorry if you know all this...

 

Marvin

Edited December 7, 2021 by Marvin

[Ahmiccc]

4 hours ago, Marvin said:

@Ahmiccc My understanding of your problem is a bit like a foot pump used to blow up a car tyre: It will achieve the pressure but not all in one go!  So like the foot pump the mains water will supply over time and the pump would slowly build up pressure.  However when you let go of the pressure by opening a tap it will slowly drop.

 

I think the pressure is fine at 2 Bar its the rate the water is flowing along the pipe (just like a small foot pump for a car tyre) 

 

In order to over come this in my humble opinion I would recommend a storage tank.  The real test is the flow rate. Go to the fastest running tap with a bucket run the tap whilst timing, until full. measure the contents and  divide the result by the minutes it took to fill this will tell you HOW FAST the water is in litres per minute. A typical shower needs between 12 and 16 litres per minute. Compare the result. 

 

If you put the big pump on the mains, sure it will suck the water but only to a maximum of one bar negative pressure otherwise a vacuum will form in the pipe.

 

I hope this helps. Sorry if you know all this...

 

Marvin

Ahhh yeah your right about PRV I shall keep it even though the pump can be adjusted but I’m thinking to set them both at 4.5bar

 

what storage tank size would you recommend for my circumstance ? I’m thinking around 100-200l

 

regards flow I’m getting around 15L/m please confirm if I’m wrong but the more open taps or shower or even using the water going to boiler coming back down to shower this will reduce flow rate ?

 

so if I want to screw over my neighbours and maybe get Severn Trent to increase the pressure I connect it straight too the mains as it will suck all the water from where it can ?

 

no no it’s fine I have an okay understanding of how this works just very unsure so want to make sure I’m going down the right direction before I invest even more and get screwed over by Severn Trent

[Temp]

15 hours ago, Ahmiccc said:

all I could get is 2.1 bar and when one tap was opened I’d get 0.75bar maximum but mainly sitting on 0.5bar and sometimes going up to 0.75bar.

 

Where are you measuring the pressure? I think that suggests there is still a restriction somewhere in the system. The pressure should not drop that much down a 32mm pipe when when the flow rate is "1 tap".

 

Check any valves are fully open including the main stopcock. If no problem found with those try and measure the pressure at the following two points both with nothing running and again with a tap open...

 

1) Near to the main in the road as possible. If this varies a lot with tap on/off then the problem is in the main not on your site.

2) Where the new 32mm pipe comes into the house.

 

If 1) is constant and 2) varies a lot there might be a problem with new 32mm pipe or the meter or anything else in it. Small stone?

If 1) and 2) are both close to 2 bar and don't change when the tap is turned on/off the problem is in the house somewhere.