Urgent help on system set-up please!

Dre

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Ok here goes...

Tap Pressure - 3.5bar. Flow rate 20l/m. No space for separate storage or header tank as loft has been converted.

1st floor - wetroom (with large showerhead and 6 body jets suggest flow rate is 18l/m for showerhead and 9 l/m for the body jet - I'm assuming this is each)

Loft - Thermostatic shower in en suite

So how do I manage to maintain the shower in the wet room? with water being used elsewhere including the other en suite shower.

- Can I used a condensing combi with a storage tank?
- Can I use a pump with this system?
- If the flowrate for the combi is greater than the incoming flow rate (20l/m) is that just a waste of money?
- Would I have a direct cold water pipe to the combi without t-offs? what benefit would this have as any other uses of the water would have the same net effect on the flow?


I've got a 15mm lead pipe coming into the property form the stopcock in the front of the house (not sure what size it is to there) 22mm pipe from the 15 once in the property.

- Will it make any difference if I change this from the stopcock ?(am I allowed to?)

Apologies for the long post and all the questions - PS I'm not a plumber just a householder with an interest in understanding what is the best can do for my house from the people with the knowledge.

I really would appreciate any help you can provide as the builder is clueless (as I would expect hes not a plumber), the plumbers I have seen have stated various differing opinions but no consistent message.
 
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A WB Highflow 550, a glow worm ultrapower sxi170, an xtramax he or a Vaillant ecotecplus 937 would be good options. Get a few quotes from local recommended heating engineers and one from Bg (just for comparison as they are VERY overpriced and not very good).
 
A WB Highflow 550, a glow worm ultrapower sxi170, an xtramax he or a Vaillant ecotecplus 937 would be good options. Get a few quotes from local recommended heating engineers and one from Bg (just for comparison as they are VERY overpriced and not very good).

Cheers Dangermouse, Had considered a couple of those as well as the potterton powermax and the Atmos.

However the same questions as those that I highlighted above kept me from making an informed decision between any of these.

Can you give any advise on these questions? Anyone else?
 
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Have to admit, you got me there.
Not 100% sure, but my guess is that even if you could, it would do little good.
If the capacity of the store is enough, you would not need a pump, and once it has run out, it is not a matter of insufficient flow, but of heating capacity.
The flow-rate of a boiler does not indicate so much the amount of water that can go through it, as the amount of water that can be heated sufficiently.
 
If I read your post correctly you need 27 litres per min and you have 20 litres per min currently.

Option 1 is get a boiler such as the WB Highflow 550 and upgrade the water main, assuming Thames Water promise you in excess of 27l/m

Option 2 is the same as option 1, but fit an accumulator instead of upgrading the water main.

You'll need a bit of spare space for option 2, typically 668mm by 1575mm high.
 
Ok here goes...

Tap Pressure - 3.5bar. Flow rate 20l/m. No space for separate storage or header tank as loft has been converted.

I expect that is a measured open pipe!

Thats NOT what you need!

You need a dynamic flow rate of at least 27 li/min with a residual pressure of say 0.5 Bar.

As you have not given any information on the lead pipe size or length then there is little help we can give you. Generally replacing the supply to the boundary with 32 mm plastic will give a significant benefit in the flow rate. Particularly if you have a supply pressure of 3.5 bar in the street as long as the pipe sizes in the distribution are good.

Tony
 
Ok here goes...

Tap Pressure - 3.5bar. Flow rate 20l/m. No space for separate storage or header tank as loft has been converted.

I expect that is a measured open pipe!

Thats NOT what you need!

You need a dynamic flow rate of at least 27 li/min with a residual pressure of say 0.5 Bar.


15mm coming in - distance just over 2m
As you have not given any information on the lead pipe size or length then there is little help we can give you. Generally replacing the supply to the boundary with 32 mm plastic will give a significant benefit in the flow rate. Particularly if you have a supply pressure of 3.5 bar in the street as long as the pipe sizes in the distribution are good.

Tony
 
Option 2 is the same as option 1, but fit an accumulator instead of upgrading the water main.

My understanding of a accunumalator is that it increases the pressure but not the flow rate?
 
My understanding of a accunumalator is that it increases the pressure but not the flow rate?
It's a funny understanding that allows you to think that you can increase one without affecting the other.
 
The relationship between pressure and flow is quite complicated.

An accumulator does not increase static pressure, but boosts flow rate within the property.

Because a higher flowrate is available from the stored water volume, the working pressure (eg: when the water is moving) is significantly improved at the taps/showers.

But if you were to measure the static pressure before and after the accumulator installation, it would be unchanged.
 
With a demand of 27 li/min excluding other water uses like WCs WMCs etc. you would need a massive accumulator to make much difference!

Accumulators work best when the flow rate is very poor to the property, like under 10 li/min AND the useage is not that high like 12 li/min.

An accumulator will give about 70% of its capacity in useful output when the static pressure is as high as 3.5 Bar.

Even a 200 li accumulator will only last a very few minutes with that kind of flow rate.

Tony
 

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