Low Flow Rate - Northumbrian Water don't seem interested

NewkieBrown

I am writing this to try and gather some advice.
My mother has a WB boiler that is 12 years old, but fires up and heats CH just fine, so I think there is no problem with the boiler.
Northumbrian Water has been out as both my mother and next door to her (who share the supply) often have issues with shower going cold.
They tested the pressure and said it was around 10Bar so that seems fine. However, the flow rate is abysmal. Very recently the shower going cold has got much worse, upon firing up the shower it goes cold after about 5 mins and then warms up again 5 mins later or not at all. This seems to be a result of next door having a leak on the property which relates to where the old outside toilets were. It does look to be a big leak but enough to cause further issues.
This property is rented so we hold little hope of this ever being addressed and the water company seemed to suggest that sending a letter was all they would do. The occupier is also not interested in the problem.

When I tested the flow rate it seems to be about 3 litres per minute, which I feel is so low it's causing the boiler to shut down.

She's mentioned she's spoken to her boiler company who have said her boiler is old and will need replacing in the next few months but I think, whilst this may be true, isn't going to solve any of the issues she's facing.

To top it off, the house she lives in was extended about 45 years ago (as were the other 6 houses in the street) but this has meant that the extensions were built over the water supply to the street so the water company have said they can't do anything about upgrading the water supply. The end of the street nearest the supply has no or very little issues with the water supply but reaching my mothers house is a constant issue and the pipe supplying both my mother and neighbours house is 15mm copper which seems completely unacceptable.

The only thing I could think of to workaround this would be to fit a polytank in the bathroom upstairs (access to the loft is almost impossible) to run cold water supply to the boiler ONLY and then have a booster pump on the flow from the polytank to the boiler due to the height between tank and boiler only being 3m which would only provide about 0.3 bar pressure.

It does seem excessive though, but the water company have been out 3 times now and are completely disinterested in solving the problem at all.

The other alternative would be writing to her MP but not sure that would move things along at all.

Any help or advice of next steps or what to try first would be greatly appreciated.

NewkieBrown

That should say it doesn't look to be a big leak

Veteransaver

If the flow rate to the boiler ( I assume this is a combi boiler?) is good (if water company claim 10 bar has that been measured at the mains cold feed to the boiler?) then it must be a problem elsewhere, eg jn the boiler or pipework from the boiler
Are there any isolator valves anywhere that are partially closed? Or flow restrictors on the shower?
Does hot water from the taps flow ok, and at close to mains pressure?
15mm pipework for mains water is normal I think. Indeed most internal piping for the mains would be at 15mm anyway.

NewkieBrown

The pressure was tested on the "hydrant manhole" which is for fire engines (I presume) outside, that was the pressure of 10 bar, but when he removed the gauge expecting it to shoot across the back lane he was surprised to see it come out like an open garden hose.
So whilst the pressure seems adequate the flow rate is not.

The flow at a tap at a similar height to the boiler is 3 litres per minute. I have now tested the flow rate in the upstairs bathroom tap and it's about 2.5 litres (which I would assume is because of the increased height?)

Looking at the pipework it goes literally into the house, then to a stopcock and from there branches off to the boiler and tap. Whilst I cannot check the flow rate at the actual boiler, there is nothing to say it would be any different to the tap, which is 3 litres per minute.

Looking at various places online they state anything below 10 litres per minute is considered poor flow with a maximum potential flow through 15mm pipe of 20 litres per minute.

I wonder if going down the route of safety might make this more more quickly as my mum said she recently had fire alarms installed for free and whilst the firemen were here they tested the water upon request of the next door neighbour and they stated if there was a fire they'd not have sufficient water flow to extinguish the fire.

Veteransaver

Is the flow you are measuring from the hot or the cold tap? 
The kitchen cold tap would usually always be directly off the mains.
Other cold taps in the house may be served by a cold water tank in the loft. Is the boiler definitely a combi boiler?
However this is really a problem the landlord should be dealing with

NewkieBrown

It's the cold tap I was measuring so that I see "uninterrupted" flow.
There is no loft tank and the boiler is a combi boiler.

As for the house which has a leak outside, the water company said they'd write to 'the' house to get to the landlord but, it's rented out to someone who has no interest whatsoever. Their garden is unkept and they had a mattress outside the house for around 6 months before it was removed.

daveyjp

3 litres a minute is abysmal and its no surprise the combi isn't heating water well.  As you state 10l is generally considered at the low end of acceptable from mains water.

Our water company consider 9l to be the minimum they will supply at.  If you have a rate well below this and you have raised a complaint already (and you have followed their advice for reasons behind low flow such as faulty tap, partly closed stop tap etc) with no resolution go through their formal complaints procedure.

NewkieBrown

Thanks for this. I did think next steps would be a complaint just wasn't sure which way to proceed to get it resolved quickly.

I will try and see what they say. It's been reported a few times and as I mentioned above, they tested it before it even gets into the house and said it was inadequate so this should address any concerns they have over whether or not I even tested as I have.

One thing to add which just supports it still is sometimes when I first turn on the tap there is a decent flow almost like normal but this subsides within a second or two.