Man I really should write a blog about all my adventures.. but I just have so little time. Anyway. A few questions about water pressure:
 

My water pressure is apparently on the low side. Plumber says it's okay-ish for 2 taps running at same time but not 3, and recommend booster.

 

1/ What I don't understand- why is it even allowed to pull water from mains, rather than let mains push the water to us? It feels "greedy" somehow, but I believe it's OK to install a pump?

2/ My builder's go-to is 

- https://www.stuart-turner.co.uk/product/mainsboost-mb-100sv-1-22-44452 and https://www.stuart-turner.co.uk/product/mainsboost-charger-wall-mount-mbc-12-28-wm-44726

 

-> this is a large amount of kit. Do we really need a tank? Of that size? Can't we just use e.g. 

https://www.plumbworld.co.uk/stuart-turner-aquaboost-abp-f120-50-1h-1-centrifugal-pressure-set-pump-44622-19703-1253840

 

Which might just fit under a sink. Do we even need a vessel? 

 

3/ I understand it's best to put it close to the incoming water mains, and also our hot water cylinder is near incoming mains, but frankly we have very little space left in that area. Is it sane/possible to put just the booster system in the loft and then drop the water back down from there?

 

Edited July 12, 20233 yr by puntloos

I fitted One at my daughters. It didn't have a vessel. It increased her water pressure to 1.5 bar. There was a single main that supplies her and her next door neighbour. Without it her water pressure was dreadful. She is single so just has the kitchen, and One bathroom, so serves her well.

7 minutes ago, Big Jimbo said:

I fitted One at my daughters. It didn't have a vessel. It increased her water pressure to 1.5 bar. There was a single main that supplies her and her next door neighbour. Without it her water pressure was dreadful. She is single so just has the kitchen, and One bathroom, so serves her well.

So what's the point of all the big vessels etc? I could understand it if we are in fact not allowed to 'pull' more water than given, since then you could use the vessel for temporarily pumping out more than is coming in, but in all other cases is the purpose only to resist certain start/stop conditions?

Perhaps he is looking to boost to more than 1.5 bar ?

The vessel is basically an accumulator, which is a cylinder with a bladder inside. One side of the bladder is water filled the other is pressurised air. The pump fills the cylinder to a pre defined pressure - expanding the bladder. When you open the tap, the pump does not run, instead the bladder pushes the water out of the cylinder - the bladder deflated as the water is used. When the pressure drops to a pre defined point the pump starts and re pressurises the cylinder.

 

You are just filling a big bucket for use later. You are not using any more water than normal.

 

It exactly the same as my borehole water.

1 hour ago, JohnMo said:

The vessel is basically an accumulator, which is a cylinder with a bladder inside. One side of the bladder is water filled the other is pressurised air. The pump fills the cylinder to a pre defined pressure - expanding the bladder. When you open the tap, the pump does not run, instead the bladder pushes the water out of the cylinder - the bladder deflated as the water is used. When the pressure drops to a pre defined point the pump starts and re pressurises the cylinder.

 

You are just filling a big bucket for use later. You are not using any more water than normal.

 

It exactly the same as my borehole water.

 

The way I'm reading your explanation (thanks for it, btw!) is that this will help ease the load on the water mains, because just connecting a raw pump to the mains will potentially drop the water pressure for my neighbours? 

 

Am I allowed to run without such a vessel and if so, would it make me a bad neighbour? Obviously I like to keep things simple, but not at the cost of others.. 

Just a quick note...you can't actually put a pump on your incoming mains which exceeds 12 litres per min...I think what you have there definitely would. You need a break tank to store the water then pump the stored water. Whole home boosters that just provide the 12litres per min are rubbish...I expect you have more than that currently.

Those accumulators are ok, although they need to be sized correctly. If you are going down the route of all this cost you are much better off spending a bit more and having a break tank you can then pump from as much as you want!

6 minutes ago, Huckleberrys said:

Just a quick note...you can't actually put a pump on your incoming mains which exceeds 12 litres per min...I think what you have there definitely would. You need a break tank to store the water then pump the stored water. Whole home boosters that just provide the 12litres per min are rubbish...I expect you have more than that currently.

Thanks, I imagined there was some 'good neighbour' limitations. 

 

5 minutes ago, Huckleberrys said:

Those accumulators are ok, although they need to be sized correctly. If you are going down the route of all this cost you are much better off spending a bit more and having a break tank you can then pump from as much as you want!

Ah, and a break tank effectively will be slowly drained while the pump pulls more water from the tank than the mains can top up, I take it. 

 

Can we hide these vessels at ceiling level or is this a matter of sucking it up and using 'real' space?

They can be quite a large affair. I wouldn't want it above my head really. You can get complete grp e closures with tank and pump the lot which I guess can be sited outside or in a garage etc.

Why not put in a shed outside. That's where my borehole equipment is. Just a simple insulated shed, doesn't need to be big. I have a simple dimplex tube heater in there. We have not had any freezing issues and we get down to -9 in winter.

My understanding is that the accumulator can be before or after the pump...

 

If its before the pump it's purpose is to reduce the peak flow rate required from the mains. It fills slowly and the pump empties it quickly. It needs to be large enough to cope with showers. Used when the flow rate from the mains is inadequate. A flow sensor is used to trigger the pump so it runs as soon as you turn on a tap. Can be used if more than one house is at the end of a long/narrow supply pipe. A large cold water vented tank in the loft feeding a pump is an example.  

 

If its after the pump it's normally to reduce cycling of the pump. Pump only runs when the pressure in the tank falls. So you can run a tap for a short period and the pump won't need to start. Can be used when the mains pressure is low but the flow rate is OK. Shouldn't be used if more than one house on a long/narrow supply pipe as it can rob the other house.  

So we measured the input flow from our mains and it came out at 24L/minute. That seems perhaps slightly slim for 3 showers at the same time but that's going to be super rare? Or do we lose a lot of pressure in the house internal pipes and the effective flow will be much less than 24 when it reaches the tap(s)?

You lose pressure dependant on the length and size of pipes due to friction, plus going uphill to an upstairs bathroom will reduce it further. My problem is the opposite as I am fed from the main connection by a 600m downhill run of pipe so I gain pressure.

 

https://en.wikipedia.org/wiki/Friction_loss

One update, does anyone have recommendations for brands of booster pumps that are QUIET (uh, but still are powerful enough to serve say 2 showers and "some third thing" at the same time from a 200L vessel)

 

Are any brands recommended or not recommended here? 

We have a Salamander whole house pump it works on negative and positive systems and you can choose 1,2 or 3 bar on the settings very easily.

 

we live in a converted barn, it was converted 20 years ago and not by us.

were listed and have 3 floors so just went for a whole house system that was easy to install. The rainfall shower that used to just drip is now very good.  We found 3 bar too much so it’s set on 2 but when we rent out we could change it to 1. It’s not really quiet but boxing it in and sound insulation and sitting it on something solid all helps. 
 

hopefully someone else will also comment.