Chaining mains accumulators

[bgmill]

To set the scene: our water supply travels around 100m under a private single-vehicle tarmac lane to the mains in the nearest public road. This was installed some 50-60 years ago and is now furred up to the point that we get a flow rate of around 8 litres per min, albeit with good pressure.

 

Due to the distance, cost and disruption of moling a new mains pipe we're looking at accumulators instead.

 

I think we'll need around 700ltr but we don't have space for such a large tank so would two 450ltr tanks in the following layout work?

 

mains --> 1st accumulator (in cold garage) --> water softener --> 2nd accumulator (in pump room inside house)

 

So essentially we'll have one tank of hard water and one tank of softened water. Is this likely to cause a reduced lifespan of the hard water tank or should we try to squeeze both in after the softener if possible?

[Conor]

Have you looked at flushing the main out? I.e. installing a temporary standpipe on the main and letting it fully open? If it's an old cast iron it may not make a huge difference, but worth a shot.

[Carrerahill]

56 minutes ago, bgmill said:

To set the scene: our water supply travels around 100m under a private single-vehicle tarmac lane to the mains in the nearest public road. This was installed some 50-60 years ago and is now furred up to the point that we get a flow rate of around 8 litres per min, albeit with good pressure.

 

Due to the distance, cost and disruption of moling a new mains pipe we're looking at accumulators instead.

 

I think we'll need around 700ltr but we don't have space for such a large tank so would two 450ltr tanks in the following layout work?

 

mains --> 1st accumulator (in cold garage) --> water softener --> 2nd accumulator (in pump room inside house)

 

So essentially we'll have one tank of hard water and one tank of softened water. Is this likely to cause a reduced lifespan of the hard water tank or should we try to squeeze both in after the softener if possible?

What is the diameter of the old pipe? Friend had a similar issue, they broke into the pipe at both ends and fed a MDPE pipe down the 100-120m lane. 

[bgmill]

2 hours ago, Conor said:

Have you looked at flushing the main out? I.e. installing a temporary standpipe on the main and letting it fully open? If it's an old cast iron it may not make a huge difference, but worth a shot.

Yeah, when we had the water co come and do a flow test the engineer put a standpipe on the stop tap on the boundary and let it run for about 20 mins into the drain between tests but no difference.

[bgmill]

2 hours ago, Carrerahill said:

What is the diameter of the old pipe? Friend had a similar issue, they broke into the pipe at both ends and fed a MDPE pipe down the 100-120m lane. 

No clue, I'll see if we can find out though as it's worth a shot.

[PeterW]

Where is the meter and the stop valve ..?? And does your iron main serve more than you ..?  If so it could be the responsibility of the water company to repair it - 8l/min is very low and I would also suspect it may be leaking in the near future if it’s a 60 year old steel pipe. 

[Temp]

3 hours ago, bgmill said:

I think we'll need around 700ltr but we don't have space for such a large tank so would two 450ltr tanks in the following layout work?

 

mains --> 1st accumulator (in cold garage) --> water softener --> 2nd accumulator (in pump room inside house)

 

From that thread..

 

Be

 very wary of fitting the accumulator after the softener if you are looking to use a Harvey or similar twin cylinder softener.  They do not like having a slightly higher pressure on the outlet than the inlet and will reward you for doing this by filling your plumbing with salty water every now and again (ask me how I know this...).  I had to re-plumb our system so the in-house 100 litre accumulator was on the inlet side of the water softener to fix this problem, as my initial fix of fitting a non-return valve on the softener outlet didn't work, probably because the high outlet pressure is still "seen" by the internal valve system within the softener that changes over from one cylinder to another during regen. 

 

If using a single cylinder softener then make sure there is a non-return valve on the outlet (single cylinder units usually have one, or specify that one is fitted).

 

You also need a double non-return valve on the incoming supply, before the accumulator, so that the accumulator doesn't back feed the main when/if the incoming pressure drops.  Normally there will be one of these on the incoming water main, next to the water meter or external stop cock, but older systems may not have one.

 

 

 

 

[bgmill]

10 minutes ago, PeterW said:

Where is the meter and the stop valve ..?? And does your iron main serve more than you ..?  If so it could be the responsibility of the water company to repair it - 8l/min is very low and I would also suspect it may be leaking in the near future if it’s a 60 year old steel pipe. 

Meter and stop valve are both on the boundary of our property (100m away from the main road). The water company claim the pipe is private and our responsibility as they have no records of any pipework beyond the main road junction.

[bgmill]

@Temp thanks, I did see that thread but I assumed that if the softener was in between two accumulators then it would have the same pressure on both sides as it's isolated from the mains.

 

[Temp]

Ah ok. So you dont plan on drawing unsoftened water from the first accumulator for kitchen sink?

[Temp]

I wonder how expensive "pipe bursting" is? (where they pull a tool through the existing pipe expanding the ground around it for a bigger pipe).

 

https://www.eps-trenchlessinstallations.co.uk/pipe-bursting.php

 

Suggests they can do 100m in a day and runs upto 150m.

[PeterW]

18 minutes ago, bgmill said:

Meter and stop valve are both on the boundary of our property (100m away from the main road).

There is your answer. 
 

Anything from the meter back to the main is the responsibility of the water company if it is not on your property. If it bursts it would be up to them to find it - which company is it ..? 

[Conor]

3 minutes ago, Temp said:

I wonder how expensive "pipe bursting" is? (where they pull a tool through the existing pipe expanding the ground around it for a bigger pipe).

 

https://www.eps-trenchlessinstallations.co.uk/pipe-bursting.php

 

Suggests they can do 100m in a day and runs upto 150m.

 

At a guess, £30 a metre for a service connection, all in.

 

From the sounds of it, I'd definitely replace the pipe. It'll be giving terrible water quality, is probably leaking like mad (likely part of the reason you've poor flow) and will fail at some point.

[Temp]

11 minutes ago, PeterW said:

There is your answer. 
 

Anything from the meter back to the main is the responsibility of the water company if it is not on your property. If it bursts it would be up to them to find it - which company is it ..? 

 

This..

https://www.ofwat.gov.uk/households/supply-and-standards/supply-pipes/#:~:text=Supply pipes run from the,property owner's responsibility to maintain.

.. suggests the pipe from the water main ttothe property boundary is a "communication pipe" or "supply pipe". As its under a private road it looks like your responsibility.

 

If there is a public footpath along the private road that might make it a highway so the company responsibility?

Edited May 17, 2021 by Temp

[bgmill]

@Temp No plans for unsoftened water to the kitchen sink no. We distil all our drinking water anyway as the chlorine is so high direct from the mains it's like gulping pool water.

 

The engineer was very insistent that the connection pipe not their responsibility but no harm getting them back to confirm that's 100% the case I suppose. This "pipe bursting" seems like a potential solution though as it will be a lot cheaper than moling.

 

@PeterW It's Anglian Water.

[PeterW]

22 minutes ago, Temp said:

As its under a private road it looks like your responsibility.

Only if you own the road. 
 

A communication pipe is a grey area - also depends on who fitted the meter and the isolator. 
 

Communication pipes carry water between the water mains and the boundary of private property. If a company stop-tap has been fitted, this will normally mark the end of pipework that is the responsibility of the company and pipework that is the responsibility of the property owner. Not all properties will have their own stop-tap in the footpath but where one has been fitted, this is normally the responsibility of the company to maintain.

 

 

10 minutes ago, bgmill said:

It's Anglian Water.

Explains it all ... had dealings with them, they are not the easiest. 

[Temp]

Good luck with Anglian Water. They were my water company. They unilaterally decided I had to pay for a watching brief from an acheaologist while we diverted a water main. The planners wernt bothered. Very disorganised. The water co team of 3 or 4 would arrive at 7.30am and sit around with the Archaeologist until 10am waiting for their excavator which never arrived. Happened more than once. Then when they were done they had to put chlorine in the new pipe for 4 weeks and test it before it could be used. They forgot to do it so we ended up waiting another four weeks.

[Nickfromwales]

+1 to attempting to replace the pipe. Accumulators ( the rubber bladder inside ) have a useable service / lifespan to consider.

1 hour ago, bgmill said:

@Temp thanks, I did see that thread but I assumed that if the softener was in between two accumulators then it would have the same pressure on both sides as it's isolated from the mains.

2x 500L acc's on the supply side will give a stable pressure range to work with, and have 500L of useful potential between them, max. Always over-size here.

The big issues from differential pressure fluctuations, I believe, are mostly caused by the stored energy being regularly / routinely depleted. Acc's should be sized / specified to retain a minimum of 30% of the stored energy for anything other than occasional adverse conditions. I'm sure there are other softener manufacturers out there that have a unit which can cope. I've fitted an acc on a Harvey unit without such issues, so maybe just down to the topology of the plumbing and a bit of sensible pre-planning in the design of the system will avoid any abovementioned problems.

[bgmill]

I've been onto Anglian Water and they're adamant that this is a "private communications pipe" and that it's my responsibility. They're saying the "controlling boundary stop" is on the main road, which was tested at 25 litres/min and 2.5bar so this is well above what's required of them.

 

I've asked them for evidence that the pipe is private and that every property down the lane has their own supply (there are 5 properties in total and we are the 2nd along). It would seem very strange that they would run a separate private pipe to each, especially considering the furthest is some 350m and council-owned.

[bgmill]

My request went to their legal dept and they've produced some detailed maps and correspondence with previous owners that does indeed suggest it's a private supply pipe that feeds 3 other properties as well as mine.

 

I'm waiting on a final quote but they've given a budget estimate of £3000 to mole a new 25mm pipe, which seems reasonable.

 

Is 25mm adequate given the distance or should we be looking to increase to 32mm?

[PeterW]

On 18/05/2021 at 09:52, bgmill said:

which was tested at 25 litres/min and 2.5bar

Ask for the proof - where did they actually test this as they can’t use the hydrant to do it. The upside is that it is a decent flow and pressure, and if they can mole a replacement then that’s good. See if they will do 32mm for a price. 
 

The only downside is if it serves 3 more properties then who is paying for their connections ..??

[bgmill]

@PeterW they shared the engineers notes from last year and, to be fair, that matches what he told me on the day just before he tested flow rate at my boundary. Having said that, there's no other 'proof' as such.

 

The new supply pipe will be just to my property, everyone else will stay on the existing shared one.

[bgmill]

As an update, I managed to get a new 32mm supply pipe installed for £1800 in the end and we're now getting ~25 ltr/min.

[Nickfromwales]

Pretty healthy rate ?