Increasing Mains Cold Water Pressure and Flow Rate

[Ryan111]

Evening All,

We have just (3 weeks ago) got the keys to our first house. Central heating and condensing boiler currently being installed. Plumber has advised that our water pressure is low (just about enough for boiler but not ideal).

I’ve bought a pressure guage and have the following readings;
Static pressure - 3.1 bar
Dynamic pressure - 0.7 bar
Flow rate - 12L/min

I’ve purchased one of the ‘home boost’ pumps but it made little or no difference to the flow rate at any tap.

I have had the water main replaced from the meter to 25mm MDPE direct to the location of the boiler to be installed and taken the readings off the end of this so no internal pipework causing poor flow rates. With the house connected I get approx 9L/min through the kitchen and bath taps.

How can I increase the flow rate? The boiler spec’d will do 16.5L/min of hot water so want to bring the cold up above that to get the most out of our new thermostatic shower that’s being fitted.

 

[kindai]

Big tank in the loft?

 

[Ryan111]

I had considered that, but the boiler is being fitted on the ground floor and running the pipe work to and from the tank would be a pain!
We have a detached garage approx 2m from the house and an open trench between that I have considered diverting the main water inlet into the garage and fitting a tank and pump system to boost water pressure and flow. I have also considered an accumulator since the static pressure is reasonable....

 

[robj20]

What about the communication pipe, what size is that?

 

[Ryan111]

I don’t know about that, I only had the customer side of the meter changed. I’ve got SW Water coming in a couple weeks to check but I’m pretty sure I’ve got above the minimum they are required to provide so they won’t do anything about it. I’m also pretty sure I’m on the end of the water main for our street so get whatever’s left over which doesn’t help matters!

 

[robj20]

I don’t know about that, I only had the customer side of the meter changed. I’ve got SW Water coming in a couple weeks to check but I’m pretty sure I’ve got above the minimum they are required to provide so they won’t do anything about it. I’m also pretty sure I’m on the end of the water main for our street so get whatever’s left over which doesn’t help matters!

You can still pay for a larger communication pipe, ours is 1/2" (4bar static, 3.5bar at 14lpm) but are paying for 25mm connection 32mm pipe to be fitted for improved flow.

 

[Ryan111]

How much are you paying to have that upgraded of you don’t mind me asking?

 

[robj20]

Had a rough quote for around £900.
Includes 32mm pipe from main to stop tap, then a further length of 32mm to under the boiler. 32mm to 25mm connection to main (32mm connection costs more but the pipe cost next to nothing over 25mm).

You have to find someone approved to connect to the mains, otherwise you will still require the water company to come out and make the connection, they wanted about the same as to do just the connection so it's a no brainer.

 

[danlightbulb]

Upsizing the water company feed might not help you if the general area cannot support increased pressure. Your area might be elevated compared to the general network, or your area might be subject to a pressure management scheme.

 

[Ryan111]

I’m going to check a neighbours pressure/flow and see how theirs compares. If theirs is the same then I’m pretty confident it’s just an area thing and I’m not going to benefit much from paying for a larger communication pipe

 

[fezster]

Home boost pumps on mains are only allowed to pump up to 12l/min, due to water regulations, which is why you haven't seen any improvement.

With your static pressure, an accumulator may work. It's also possible your static pressure increases overnight, when there is less usage.

Otherwise, a break tank and then a pumped setup is your only option, unless the water company can do something about your communication pipe.

 

[Ryan111]

I figured that’s why the Home boost pump didn’t have much effect on my flow rate.

I’ve been looking at a system such as this - https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/172668430075

Would a break tank work in the garage being the lowest part of the house? If so, can anyone recommend a suitable tank/pump combo to feed the combo boiler and cold water to the house?

 

[wilber]

Home boost pumps on mains are only allowed to pump up to 12l/min, due to water regulations, which is why you haven't seen any improvement.

i was complaining to my installing about the poor flow rate and why such a small pump had been installed for my needs, I was told 20l/min was the maximum for for a mains connection. I'm on a private supply so they're replacing with 60l/min.

 

[fezster]

i was complaining to my installing about the poor flow rate and why such a small pump had been installed for my needs, I was told 20l/min was the maximum for for a mains connection. I'm on a private supply so they're replacing with 60l/min.

https://www.wras.co.uk/plumbing_professionals/advice_for_plumbing_professionals/installation_faqs/

Q. CAN A PUMP BE INSTALLED ON A SUPPLY PIPE TO BOOST LOW PRESSURE?
A. Yes - Pumps are allowed to be installed on supply pipes. However if the pump is capable of delivering more than 12 litres per minute, you must notify your water supplier and seek their consent before starting any work. Notification Page >>

 

[wilber]

https://www.wras.co.uk/plumbing_professionals/advice_for_plumbing_professionals/installation_faqs/

So it's possible he can have a 20l/min pump, just needs to inform his supplier.

 

[a1ex2001]

So it's possible he can have a 20l/min pump, just needs to inform his supplier.

and wait for there approval which they are unlikely to give in an area where they are already struggling to deliver good flow rate!

 

[Countcussy]

Storage tank and boost pump is the way to go.
As others have said, you cannot improve what's not there. An expansion vessel on its own is an option, but its not always as good as expected.
The link you showed on ebay is what I would call a traditional pump set, with pump and expansion vessel.
Depending on budget, there are many more efficient and quieter options available, including variable speed systems which don`t require a large expansion vessel and are much, much quieter. Running costs are lower too.
The storage tank is the tricky bit as you need the space, but Well worth it if you have.
Put the tank and the pump in the garage and you are sorted.

Not sure I am allowed to link to my business website, but we have many options.
I`ve been involved in water pumps for over 20 years. If you want any help or advice, just ask.

 

[amkan13]

your static pressure seems to be decent, an expansion vessel/accumulator (in the loft for example) would help for peak water flow you require. you will not be able to use the full capacity of the expansion vessel/accumulator however, it needs to be oversized.

 

[Ryan111]

Budget is one of those things I am not set on. I don’t want to spend £300 and it still be poor, but then also don’t want to spend £800 if I don’t need too.

We have the space for a storage tank, so that is definitely an option. It is only the two of us at the moment, so Water needs aren’t massive but I would like to somewhat future proof the design at this stage rather than trying to do it retrospectively.

I’ve been looking at a 2-300L storage tank, I’m guessing this is in the right ball park? Can you recommend a suitable pump/tank combo? Af far as I’m aware you can link to other sites as long as it’s not a competitor and OCUK don’t sell water pumps/tanks (atleast not for domestic water anyway!) so there shouldn’t be a problem there...

 

[Countcussy]

Something like this.
https://www.whisperpumps.com/Dab-ESybox-Mini-Water-Pressure-System
Attached to a tank would give you fabulous flow and pressure. Variable speed means it only works as hard as hard as it needs to.
Open more taps, and pump speed increases, maintaining constant pressure.
If you go to the pressure boosting section of the site, you will see the major brands, as well as systems designed and built by ourselves in house.
On the site you will find tanks as well, although it's possible your plumber may have more suitable options. If you have time to chat, call the main number tomorrow and ask for Mark. Should be able to sweeten the price also.