Looking for a pressure pump not in excess of 12l/min

[EuroSong]

Hi - I'm wondering if anyone can help me. I'm looking for a water pressure booster pump, which is unable to deliver more than 12 litres per minute flow rate. Let me explain.

I live on the top floor of a block of flats. I have a combination boiler. The pressure during the day is just fine, but at night it reduces significantly. To have a shower when the pressure is low in the evening is not a nice experience: and sometimes the pressure is even so low that the boiler stops working.

The water company (Thames Water) deliberately turn down the pressure at night because they want to reduce leakage, in order to meet targets to avoid a fine from OFWAT (the water regulatory body). It's a disgusting practice, but at the moment, it continues.

As I live in a flat, space is extremely limited: we do not have any loft space, so installing a water tank and pump is out of the question. There is simply no space anywhere for a tank.

What I want to do, therefore, is to just install a pump - connected directly to the mains. I have done my research, and found out that it is not permitted to connect a pressure booster pump directly to the mains supply without written permission from the water authority. I asked them about this - but they want to charge £885 merely in order to carry out a survey - with no guarantee of saying yes at the end! There is no way on Earth I am paying that - especially considering that it is not my fault that they are turning down the pressure to avoid fines due to their own lack of investment in fixing their leaks. Anyway...

There is a loophole, however: It is permitted to install your own pressure pump directly to the mains - as long as the pump can not deliver a flow rate in excess of 12 litres per minute.

I have measured what 12 litres per minute feels like for a shower - and found that it is absolutely fine. In fact, our shower delivers 10.8 litres per minute during the daytime, when the pressure is still okay. So a "limit" of 12L/min is not a problem at all - as long as the pump boosts the pressure more than 0.3 bar, which is what it drops to at night!

One problem, however: as much as I search Google, I can not find any domestic water pressure boosting pumps which deliver a flow rate not exceeding 12L/min. The only things I can find are low-voltage pumps suitable for caravans and boats etc. It is a mystery to me why this should be the case. Surely the pump manufacturers should know what the water regulations permit, and if they produced pumps which delivered good pressure - but limited flow rate accordingly - then they would be able to sell to this market.

So - can anyone help me? Does anyone know of any suitable domestic water pressure boosting pumps which do not deliver more than 12L/minute? A 240-volt pump would be preferable: I really don't want to have to mess about with a transformer!

 

[mehran]

i have no idea if it is limited to 12l/m but you can get a smallish pump called "Grundfos Small Appliance Booster Pump UPA 15-90"

you could fit a flow restricter i guess to make sure it is limited to 12l/m... or just dont tell anyone you had it fitted

 

[mickyg]

have you had the static pressure and flow rate measured? although the legal requirements are pretty lame, its still worth checking they've been met.

 

[EuroSong]

The pressure was logged by a pressure logger installed at ground level, after I initially complained to Thames Water. They went through a whole rigmarole of denying that they were doing anything - and it's only after I had the data from the logger that it was plainly obvious: every night between midnight and 05:00, the pressure at ground level drops from 3 bar to 1.5 bar. Thames Water state that they're only legally obliged to provide 1.0 bar at ground level - so they're technically fulfilling their obligations.

With 1.5 bar at ground level - and with our bathroom being on the fourth floor - we only get 0.3 bar in our shower at night. It's rubbish. What's more worrying is that if Thames Water were to drop right down to their legal minimum of 1.0 bar at ground level, then because our flat is more than 10 metres from the ground, we would get no water at all!

I measured the daytime flow rate myself by using the shower to fill a bucket while timing it. As previously stated - 10.8 L/min is fine, so we would have no problem with 12. I believe the night-time flow rate is around 4 L/min.

I took at look at the Grundfoss pump suggested: it appears that the flow rate is 1.4 cubic metres per hour - or 23 L/min. Now, I'm wondering if the water regulations are interpreted as that the pump itself must not be capable of exceeding 12 L/min - or if it's okay to have a higher-flow pump used in conjunction with a flow restrictor. I read the regulations, and they don't specify precisely. Can anyone advise?

With regards to "just don't tell anyone" - well, I am no plumber: I would have to get a professional in to do the job. And I'm quite sure that no professional plumber would want to put his certification at stake by knowingly breaking the regulations. So I want to nail it down in black and white...

 

[mickyg]

must confess, there's not many flats round my way so I haven't had dealings with this situation, and having just browsed over the regualtion it looks like your screwed. Unfortunately I'm not aware of an actual pump designed for purpose. The only pump I know designed to pump the main is the mainsboost charger set, but thats designed to work alongside an accumulator AFAIK. Still they might be the people to ask.

 

[mehran]

i am not a London plumber but i would be more then happy to install a pump like this. the water company sounds like evil money grabbing bastards. the fines are there to stop them wasting water not to reduce service.

the only thing i would worry about is if it negatively affect your neighbors supply when running the pump.

 

[EuroSong]

You're absolutely right Mehran. Thames Water just can't be bothered to invest in fixing their leaking pipework: instead of doing so, they just turn down the pressure to avoid fines. Then they have the nerve to ask for £885 to carry out a survey! So - do you ever come to London?

Mickyg: I looked at the "charger", but it is not suitable because the accumulator tank is large. As previously mentioned, space is an issue. We have no space for any large tanks. It's all very well suggesting these things when you live in a house with a garage and attic space - but we have neither. We need a pump by itself. By the way, how do you figure I'm "screwed"? As stated, I am unsure of precisely how the regulations may be interpreted - but I'd like an explanation and example before any conclusion.... Still, it seems incredible that there isn't a pump designed for this. All the manufacturers have to do is procude a pump limited to 12L/min and they have a whole new market: everyone who wants to boost their mains supply!

 

[simond]

We used to use the Grundfos pump in front of accumulators to increase the pressure by about a bar.

You can fit them with an adjustable bypass to lower the litres per minute across the pump head.

In a multi occupancy dwelling there is the danger that your water 'extraction' will cause neighbouring properties to get a far worse service than before.

If you haven't the room or budget for the mainsboost charger then I suppose the Grundfos Homebooster is the best solution for you.

 

[EuroSong]

Simond: The Grundfos Home Booster measures 600mm x 1000mm: it's a big tank, and we don't have any room for it. The only viable solution in my home is to just use a small pump alone - which we do have room for - as long as it's okay to fit one which is incapable of delivering more than 12L/min.

Now, the question remains: would it still be water-regulation compliant, if I can't find a pump which is restricted to 12L/min - but I find one which delivers more than that, but fitted in conjunction with a flow restricter - so the entire set-up does effectively limit the flow?

 

[RigidRaider]

I know people who live in cities like Damascus and Amman where water is actually rationed. During the few hours a day when it is supplied everybody's pumps kick in as they refill their tanks. Nightmare.

 

[mickyg]

By the way, how do you figure I'm "screwed"? As stated, I am unsure of precisely how the regulations may be interpreted

well, basically, the way I interpret the regulation is that the water companys obligation is to provide a minimum of 1 bar to the boundary of your property. But being in a flat, the boundary becomes the boundary of the land that your building sits on, which is of very little use to you as your water still has a long way to travel and lots of people using it on the way. Additionally if your property is higher than their water tower, they basically say tough sh$t can't help ya. There's also some hidden regulation somewhere that obligates them to provide about 9l/min but again only to the boundary. I'm glad I don't have much dealing with apartments as this sounds like a pain in the ar5e. I personally would be a little worried, as others have mentioned, that by using a pump you could rob your neighbours of their supply. You wouldn't be very popular!

 

[simond]

And if they don't achieve the statutory minimum I think the compensation is under a tenner a year.

If I was in your shoes I think I'd want to make room for a solution. Having enough water is rather fundamental.

 

[EuroSong]

Mickyg: You're right - the water company is currently only obliged to provide decent pressure to the ground floor boundary. And yes - since I have no control over the pipework over the three storeys between the ground and my own flat, I suffer low pressure because of it.

However, with regards to sucking neighbours' properties dry, I doubt that would be a problem: it is pressure which is being reduced, not flow rate. I am currently able to draw 11.5 litres per minute through my boiler during the daytime - as, I suspect, are my neighbours. And if it's fine to do that currently, then it should also be fine to do that at night when the pressure goes down. My neighbours would still get their existing pressure - and the water which is to be pumped to my property would simply be replaced by more from the main, at the same flow rate. Since it's not the flow which is being restricted, it should be okay.

I just need to find a viable - and legal - pump setup.

 

[simond]

My neighbours would still get their existing pressure - and the water which is to be pumped to my property would simply be replaced by more from the main, at the same flow rate. Since it's not the flow which is being restricted, it should be okay.

That won't be the case, fluids don't work like that.

 

[EuroSong]

That won't be the case, fluids don't work like that.

Oh? Well... if it does affect anyone else, it will only be for very brief periods after midnight - 5 minutes at a time for a shower. We won't be using a pump to fill baths or anything like that. And besides - any neighbours with tank systems would not be affected at all.