Upgrading water mains to 25mm MDPE, Internal piping 15mm

[k8581]

Hello,

I live in a house which has 3 bathrooms with an unvented water heating system (megaflo). Currently the size of water mains coming into property is 15mm lead and hence the problem is when the bath tap is turned on in the first floor bathroom, there is no water in the second floor shower.

I am trying to upgrade my water mains from 15mm to 25mm MDPE (apparently the water utility company wouldnt let me upgrade to 32mm)

All my internal piping is 15mm, even the one that runs from the megaflo located on the first floor to second floor bathroom.

I have few questions:

1) By upgrading the mains to 25mm, will it resolve the problem? i.e. will I have enough water flow and pressure in all bathrooms if the taps are used at the same time even if the internal piping is 15mm all across?

2) The feed coming into property straight goes into water softener - is this an issue?

3) The distance from the street boundary to internal stopcock is roughly 10 metres. I have got a quote of £1,360 plus VAT which includes upgrading mains, reinstating the paved blocks in driveway where there will be holes and reinstating the disturbed concrete floor in the house - again a size of small hole that will be done to replace pipe. I feel the cost is too high. Your thoughts?

Thanks

 

[Agile]

Oh dear!

The water co cannot prevent you from having your choice of water pipe size.

They can insist on a 25 mm max meter and communication pipe.

But from your boundary on you can have 32 mm and I would strongly recommend that with 10 m of tube that you do fir 32 mm.

Many water softeners do have a significant internal resistance. You need to see exactly what it is passing. Some are whole house whereas traditionally they were only fitted on the boiler to protect it.

Its impossible to predict what improvement you may get and more so because you have given us absolutely no technical details.

Of course some Japanese have ultra sensitive skins and need a softener on any water that they touch. The rest of us can manage with no softener or just on the hot water.

Tony

 

[k8581]

Oh dear!

The water co cannot prevent you from having your choice of waer pipe size.

They can insist on a 25 mm max meter and communication pipe.

But from your boundary on you can have 32 mm and I would strongly recommend that with 10 m of tube that you do fir 32 mm.

Many water softeners do have a significant internal resistance. You need to see exactly what it is passing. Some are whole house whereas traditionally they were only fitted on the boiler to protect it.

Its impossible to predict what improvement you may get and more so because you have given us absolutely no technical details.

Of course some Japanese have ultra sensitive skins and need a softener on any water that they touch. The rest of us can manage with no softener or just on the hot water.

Tony

The water flow is 12 litres per minute in an internal tap feeding directly from mains and pressure is 3 bar - confirmed by water company

 

[Agile]

That is an open pipe flow rate.

The 3 bar pressure is a static pressure when you are taking no flow.

That means you have a significant flow resistance in your supply.

Not very good!

Tony

 

[Madrab]

12L/min is the minimum that the distributor should deliver as part of their service delivery to you. Interesting to see what the dynamic pressure would be but @ 3bar static you really should be getting more than 12L/Min. Where did they test it?

You need to test from a point inside your house as close to the stop cock as poss. Litre bottle and time how long it takes to fill, divide 60 by the time = L/min. You'll need a gauge to test the static and dynamic pressures

 

[k8581]

Yeah, +1.

12L/min is the minimum that the distributor should deliver as part of their service delivery to you. Interesting to see what the dynamic pressure would be but @ 3bar static you really should be getting more than 12L/Min. Where did they test it?

You need to test from a point inside your house as close to the stop cock as poss. Litre bottle and time how long it takes to fill, divide 60 by the time = L/min. You'll need a gauge to test the static and dynamic pressures

 

[k8581]

Today, I got the pipe upgraded from the external stop cock to the internal one. The old 15mm lead pipe was left in as redundant and a new 32mm MDPE pipe was installed from external stop cock. The pressure on the internal stopcock is 5bar but flow rate is still low and the pressure from megaflo is 2 bar. I am still not able to use 2 taps in the bathroom (bath and sink) at the same time. If you turn on the bath, the flow in the sink tap dies.

With such a good pressure and 32mm MDPE pipe can you think of what is restricting the flow rate? Is it water softener?

 

[flameport]

With such a good pressure and 32mm MDPE pipe can you think of what is restricting the flow rate? Is it water softener?

Possibly - bypass the softener to find out.
If it's been fitted correctly there will already be valves installed to bypass the thing.

 

[k8581]

Bypass from water softener didnt work.any other ideas what could be restricting internal flow rate despite 25mm mdpe coming in with a 5bar static pressure?

 

[k8581]

More update - the flow rate on one of the cold water tap (feeding directly from cold main via softener) is 15 litres per minute - still not enough with 25mm MDPE. However when the pressure is checked from a kitchen cold water tap which feeds from megaflo, the flow rate drops to 6litres per minute. I know kitchen cold water tap should not feed from megaflo but it does. There is a pressure reducing valve before cold water mains feed softener and that has a static pressure of 5 bar and dynamic of 3.5 bar. The gauge in megaflo which sits below combination valve shows 2 bar pressure.

Happy to provide more information if anyone needs it.

 

[Agile]

But what pressure does the Megaflow gauge show when you take 10 litres per minute from hot taps?

When was it last serviced?

Tony

 

[Agile]

The old lead pipe would have been worth a few pounds as scrap!

 

[k8581]

No idea when was megaflo last serviced and even if it was, it was def before 15 months. Left the lead pipe in there. There was no reason to pull it out as the contractors could bypass the new line without touching the lead

 

[Madrab]

Need to get your Megaflow serviced by a qualified engineer. There could be a valve that feeds the megaflow that needs adjusted/repaired/cleaned. The kitchen tap (mixer?) is probably being fed from the balanced supply. Does the gauge on the megaflow drop when the hot taps are opened?

 

[k8581]

No the megaflo pressure doesnt drop when a hot tap is on. On the megaflo it is written that operating pressure should be 3 bar but its only 2 bar. How frequently should megaflo be serviced and how much does it cost? Thanks