Water pressure problem
- Thread starter david3331
- Start date
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20mm Mdpe pipe from the street is usually sufficient, however going bigger costs little more as the cost is in the dig.Would there be a whole lot of sense in installing a 32 mm pipe outside and leaving the 15mm inside the way it is?
15 mm internal is not usually a problem.
Most of the problems i encounter are due to 5Lb lead supply pipes which have the diameter of a pencil IF they are not furred up.
I had one customer 20m from the road with 3 m under the floorspace.
Replacing that 3m with 15mm doubled the flowrate, one very happy customer.
The bore of the pipe was furred down to about 4mm.
Best to have a plumber test the flowrate at the stoptap first though to eliminate the possibility of an internal problem.
A colleage of mine found the stop tap blocked, 1/2 hour fix as opposed to a digup.
Maybe, maybe not. Bit pointless though to do only half the job.
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The boiler does not support waterflow, period. It's like a car driving on a road; the road can be too small for the car to reach topspeed, it can never be too wide.
The boiler needs a certain amount of water to reach its maximum performance, depending on required temperature diffential between 12 and 20 l/min max.
As this will always be a branch off form the principal supply, if the incoming mains in the house is 15mm, any water use in the entire house will effect the performance of the boiler.
Your problem can be solved without recourse to a new main.
Sometimes a new main is the cheapest and best option, sometimes it is not.
I can't make a recommendation until you have the static water pressure reading and the flow rate, not just the flow rate.
The maximum hot flow rate of your boiler is about 13 litres per min at 42 Delta T. Allowing for a cold water blend, two showers are achievable with a better cold water inlet supply.
Please bear in mind that what the water supplier will deliver, whether through a 63mm, 25mm or 32mm main, is up to them and local conditions. You could install a 32mm main from the pavement and still have 10l/m.
As such, the advice being bandied about by some on here is optimistic at best, thoroughly misleading at worst.
Sometimes a new main is the cheapest and best option, sometimes it is not.
I can't make a recommendation until you have the static water pressure reading and the flow rate, not just the flow rate.
The maximum hot flow rate of your boiler is about 13 litres per min at 42 Delta T. Allowing for a cold water blend, two showers are achievable with a better cold water inlet supply.
Please bear in mind that what the water supplier will deliver, whether through a 63mm, 25mm or 32mm main, is up to them and local conditions. You could install a 32mm main from the pavement and still have 10l/m.
As such, the advice being bandied about by some on here is optimistic at best, thoroughly misleading at worst.
If you want to know what flow rate you will receive when you upgrade the main the only person that can provide that assurance is your water supplier (Thames Water, I assume).
No one here can tell you.
We don't even know where you live, and you don't know whether you are conversing with a B&Q weekend bodger or a heating engineer.
No one here can tell you.
We don't even know where you live, and you don't know whether you are conversing with a B&Q weekend bodger or a heating engineer.
It is impossible to say what you need to do exactly in order to get 2 properly working showers without seeing the situation and doing taking measurements
What I can say without seeing things is that it is fairly unlikely it will all work according to plan if part of the mains between the streetvalve and the main usage points remains 15.
It might make it easier for you to see the watersupply as a tree; it is fine to have small branches at the extremities, but the tree will keel over if part of the trunk is cut down to a quarter of what it should be, regardless if that bit is under ground or above.
Simon has said pretty much what you need to do.
Get measurments of pressure and flowrate first.
9L min as you have measured is an indication but some mixer taps restrict flow and can give an erroneous reading.
Before you get someone in however it would be a good idea to check the outside stoptap is fully open if there is one.
Get measurments of pressure and flowrate first.
9L min as you have measured is an indication but some mixer taps restrict flow and can give an erroneous reading.
Before you get someone in however it would be a good idea to check the outside stoptap is fully open if there is one.
well i have been speaking with different plumbers during the last 2 weeks and I have been advise
1st new main water supply + new boiler just for the new bathroom
(If I extend the pipe to 32 mm, do I need to fit a new boiler just for this bathroom or will be enough with the new pipe)
2nd water tank + pump.
Also I have checked the flow on my garden tap and in 1 minutes was 28 liters on my mixer kitchen tap was only 9 liters???
how can be possible!!!
just trying to find the best proffesional advise
hope to hear from you soon
Many thanks
1st new main water supply + new boiler just for the new bathroom
(If I extend the pipe to 32 mm, do I need to fit a new boiler just for this bathroom or will be enough with the new pipe)
2nd water tank + pump.
Also I have checked the flow on my garden tap and in 1 minutes was 28 liters on my mixer kitchen tap was only 9 liters???
how can be possible!!!
just trying to find the best proffesional advise
hope to hear from you soon
Many thanks
Worcester Bosch 42 CDI is a good boiler.
If you get 28 litres per minute from another tap, your water is fine.
Conclusion: you don't need new water supply and certainly not a new boiler; your new shower will be fine provided your pressure is sufficient.
If you get 28 litres per minute from another tap, your water is fine.
Conclusion: you don't need new water supply and certainly not a new boiler; your new shower will be fine provided your pressure is sufficient.
sorry to get you in to your nerves bengasman but...
If I open the shower tap and then open the hot water basin tap the pressure on the shower goes down quite a lot it's that mean not enough pressure (I think so..)
so my problem it's that i called some plumbers but nothing clear as they give me different solutions.
If I open the shower tap and then open the hot water basin tap the pressure on the shower goes down quite a lot it's that mean not enough pressure (I think so..)
so my problem it's that i called some plumbers but nothing clear as they give me different solutions.
Nope, it means that you have a flow restriction somewhere.
The pressure is measured with a pressure gauge with all taps closed.
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