Mains water pressure boost pump

[clankypipes]

I was hoping to get a professional opinion regarding whether or not a booster pump (such as a Stuart Turner 'Flomate') would do what I want it to do.

At present the flow rate in our house isn't terrible - about 10 litres per minute at its best - but that doesn't seem to go far if more than one tap is turned on. The biggest problem is that if you are having a shower upstairs and someone else turns on a cold tap, the flow through the combi boiler drops below the level at which it will work, and you lose hot water completely. And if, alternatively, you are using the electric shower downstairs, then the same thing happens when a tap is turned on, the flow rate dropping below the level at which the the shower will function.

I only recently found out that in-line boosters exist. They claim to add up to 1.5 bar of pressure, and guarantee a flow rate of 12 litres per minute. I am guessing that adding one to the mains pipe coming into the house wouldn't actually make a huge difference. But what if I add one just for the hot water and downstairs bathroom? Like this...



Would this set-up prevent the hot water from cutting out in the situations described? I realise that this may end up meaning that the other taps in the house are starved of water whilst someone has a shower, but this seems like a better situation than the current one.

Any advice would be greatly appreciated.

On a separate note, I can only find two options for the pump: the Flomate mentioned above, and the Salamander 'Home Boost'. Does anyone have any experience of either / recommendations / warnings etc? The Stuart Turner one seems to have a better guarantee and is slightly cheaper.

Thanks in advance!

 

[Tjdservices]

Hi, before you start check with your local water authority if you will even be allowed to fit it.

 

[Rckape]

I'm familiar with salamander as a brand as I've been fitting their shower pumps for years. I know that's probably the way I would lean.

However as TJD mentioned, it's essential you contact your water supplier and obtain written permission to install a pump directly on the main.

 

[clankypipes]

As far as I know, that's the point of those two pumps: because they only assist up to 12 l/m you can legally attach them direct to the mains without needing a break-tank.

Copied this from the Salamander website:

Is it legal to pump incoming mains water?
Yes, HomeBoost® conforms to The Water Supply (Water Fittings) Regulations (1999), which state that you cannot pump more than 12l/min off the mains supply pipe. HomeBoost® will increase the low incoming water flow up to 12l/min. As the incoming flow varies, HomeBoost® will adapt to maintain 12 l/min, and will move into idle if sufficient flow is received from the water main. The water contacting components are all WRAS compliant materials.

 

[Tjdservices]

Yes it's legal but you can not fit a mains boosting pump without permission from the local water authority.

 

[Rckape]

Again, TJD is right.

You need permission because the water supplier will have an overview of everything in your area. If too many people have booster pumps then it's possible to overdraw the supply.

This can cause a negative pressure in the supply pipe which can cause backflow in to the main with possible contamination or could even cause a fragile old main pipe to fracture.

 

[Tjdservices]

Much better explanation Rckape than mine.

 

[Unregistered]

Thanks for the replies.

I Googled it, and the WRAS website says that you don't need permission for pumps below the 12 l/m limit:-

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.

However, I'm not averse to giving the water company a call to check and make sure it's OK.

So... assuming that I either don't need permission, or I can get permission, would the set up in the diagram work?

 

[chris watkins]

Yes it's legal but you can not fit a mains boosting pump without permission from the local water authority.

Again, TJD is right.

You need permission because the water supplier will have an overview of everything in your area. If too many people have booster pumps then it's possible to overdraw the supply.

This can cause a negative pressure in the supply pipe which can cause backflow in to the main with possible contamination or could even cause a fragile old main pipe to fracture.

Sorry guys but you are not correct on this one please refer to your WRAS guide 3.16
Written consent is deemed to be given if pump connected either directly or indirectly to the mains supply does not draw more than 0.2 l/s (12l/m)

If you hold the Water Regs you should be self certificating this.

 

[Tjdservices]

Sorry guys but you are not correct on this one please refer to your WRAS guide 3.16
Written consent is deemed to be given if pump connected either directly or indirectly to the mains supply does not draw more than 0.2 l/s (12l/m)

If you hold the Water Regs you should be self certificating this.

but if you don't hold the regs you need consent as you can't self certify?

 

[Rckape]

Sorry chaps, my bad. Chris is absolutely right.

I'm fortunate enough to live and work in an area where boosters aren't required. I should have looked it up before spouting off.

 

[chris watkins]

but if you don't hold the regs you need consent as you can't self certify?

If you don't hold the Regs you should not be installing anyway, but thats not the point.
Page 5 Notifications see table - 4. (d) "a pump or booster drawing more than 12 litres per minute , connected directly or indirectly to a supply pipe;"

So if not more than 12 there is no requirement to, please trust me on this.

 

[Tjdservices]

If you don't hold the Regs you should not be installing anyway, but thats not the point.
Page 5 Notifications see table - 4. (d) "a pump or booster drawing more than 12 litres per minute , connected directly or indirectly to a supply pipe;"

So if not more than 12 there is no requirement to, please trust me on this.

Not not trusting you Chris just asking.

 

[Rckape]

Now the regs are all cleared up, back to the original question...

Yes it would work as set out in the diagram. I would give consideration to fitting it on the cold main feeding the whole house though.

Some mixer taps and shower valves don't work well with differing pressures between hot and cold. Fitting the pump on the cold main before any tee's will ensure a balanced pressure across the house.

This may be splitting hairs though, without knowing how much of a pressure increase the pump will produce.

 

[clankypipes]

Thanks very much for that - appreciate getting an expert opinion.

I'm about to fit a new kitchen and bathroom, so if I do decide to fit one as per my diagram, then I'll know that oddities with any new mixer shower could be a result of the pump rather than a fault with the shower.