Wisdom of pumping off the main...

[digdilem]

I know the bylaws say no, but how likely is a prosecution for putting a pump directly on a rising main? I know it's a risk, but how often does anyone get done for it?

I'd like to pump hot water to my kitchen tap, which is a long run from the hot water tank on 15mm with very little head (bungalow), so takes a long time to come through. While I'm there, I'd like to also boost the mains-fed supply so I've got a satisfying amount of water coming through.

We have little more than 1.2 bar and sod all flow on the main, despite the roadway main having 12bar (replaced a few years ago). Unfortunately, the 25mm black pipe supplying only us from the stopcock was threaded up through the unused cast iron main to save digging a trench and it's long, twisty and rubbish.

As this supply only affects me I know I won't be affecting anyone else by doing this, and this is a kitchen tap, drinkable, so obviously can't be fed from the loft tank.

Legality aside, is there any other issues with pumping a mains supply - such as the pressure reducing valve getting in a pickle, or any technical reasons why it's a dumb idea?

 

[Elkato531]

If your supply pipe from the main is so bad that 12 bar can't push enough water down it I doubt a pump would have much effect.

Do the job properly and replace the supply pipe.

 

[big-all]

what you are suggesting can pull pollution infection and very dodgy bacteria from other houses
the idea is the water is safe because no cross contamination can take place because the positive pressure keeps the contamination out the public supply

your idea will draw all sorts off crud from surrounding houses into your system good luck as you dont dont seem to care about your health

 

[digdilem]

Do the job properly and replace the supply pipe.

I would like to, but alas neither the water company nor myself have any easements for the existing pipe, and to bring in a fresh one over my land will mean moving the stop cock 20m up the road.

 

[digdilem]

what you are suggesting can pull pollution infection and very dodgy bacteria from other houses

I did say there's nobody else on this leg. Not sure there are any health risks provided the pipe isn't already leaking, although I guess there is a possibility of collapsing it if taken to extremes.

 

[sherbert]

Im a bit confused

I always thought that pressure remains constant so if there was 12 bar?? in the street providing no water is being used then you should have 12 bar at your house not 1.2 bar

Either there is a pressure reducing valve somewhere or you misunderstood and they said 1.2 bar and you thought 12

Have never known any mains to be 12 bar as the leakage rate would be huge

If you decide to put a pump on it then it can be done - Grundfos make a home booster pumping set thats about £1400-
If you think that you can put some heath robinson single impellar shower pump on it then I suggest that you are a fool

Sherbert

 

[digdilem]

Pressure is only constant when it's built up and equalised. If the flow rate is not there, as soon as you draw off it drops down rapidly as the flow cannot build it back up again fast enough.

12 bar is what the testers said when the new street main was commissioned. I've adjusted the PRV hugely to no effect (both left and right) To be honest, the pressure is not the main issue, it's the flow which sucks and I attribute that to a long stretch of 3/4"

What's different about the £1400 pump that allows it to work where another wouldn't? Just built better?

I may be a fool in theory, but not in practice as I'm asking first. Cheaper to find out the folly first where the only thing hurt is my reputation. Pumping off the main seems to be something where people instinctively say "No, thou shall not!" without actually explaining why.

 

[ALEC1]

yes break tank and pump or accumulator are the solution... not pumping off the mains...which will sorely dissappoint...

 

[dumbrill]

How long is the pipe from the road to the house?

 

[Ray84]

yes break tank and pump or accumulator are the solution... not pumping off the mains...which will sorely dissappoint...

if youve got the space a break tank then boosted by a pump would be ideal. Last pump i bought was on the net from ireland workedout a good bit cheaper

Ray

 

[mickyg]

if you really have got good static pressure then an accumullator would work as well.

 

[Agile]

12 bar is what the testers said when the new street main was commissioned. I've adjusted the PRV hugely to no effect (both left and right) To be honest, the pressure is not the main issue, it's the flow which sucks and I attribute that to a long stretch of 3/4"

What PRV have you adjusted?

Is the supply to your property at 12 Bar static?

If there is a PRV as there should be then how do you know thats not faulty?

Your adjustments to it have done nothing and probably would not appear to eiher.

The home booster punp set seems the answer.

What is the open pipe flow rate?

Tony

 

[Nige F]

A break tank ( actually a cistern ) is simply a cistern like in many roof spaces with a byelaw 30 kit and part 2 ballvalve , feeding any kind of pump you like because you have isolated your plumbing from the water suppliers "wholesome" ( potable) water in the mains - check out the exact regs. wherever they may be ( I was never one for paperwork ) and if you comply then you`re . I take the view that if you isolate your water from the suppliers water, you can do what you like with it - pass it over the ashes of a saint and call it holy water for example

 

[Nige F]

, and this is a kitchen tap, drinkable, so obviously can't be fed from the loft tank.

?

Not so, you can have the break tank storing potable/wholesome water

 

[doitall]

Untitled

• doitall
• 23 Jan 2011
• 2

Indeed you can, and have all the water you can dream off.