24 jet power shower- can a hotwater tank be filled by combi?

[GTO NEMESIS]

Hi!
I am finally getting round to sorting my bathroom out.
We have purchased a shower/bath unit but I need to up the pressure to a minimum of 3 BAR but up to 5 BAR.

I currently have a combi boiler that feeds my existing shower and a cold tank on the 3rd floor (bathroom is on the ground floor). The water pressure is pretty good in the shower but nowhere enough for what we need.

This is my plan:

Fit a large hot water emersion style tank on the 3rd floor and pump it to the shower/bath unit.
Now, as I understand it my shower unit will empty a 160L tank in 8 mins at maximum flow.

On this basis the tank will get very empty and it would take ages for the electric heater in the said tank to heat up that amount of water ready for the next shower.

My plan or thought is to plumb the hot water from the combi boiler into the emersion-heated tank instead of cold, therefore giving me a tank full of hot water in a couple of minutes instad of 30-40 minutes.

I have spoken to my plumber friend who said he had not seen it done but could sort of see my logic…

By my maths I don’t think the combi could supply a constant flow for us to use the shower unit at maximum flow for more than 10 mins but I doubt we would want to anyway. That said we do always shower pretty much one after the other and when we have guests we don’t want to be waiting 30 mins at a time for hot water.

What do the voices of reason say?

Here is a picture of it as you may of fitted one before, hence understand the need for lots of water.

Mark

PS: I live in Iver - South Bucks (10 mins from Heathrow)
Are there any plumbers near me that want to give a quote for a full bathroom job?

 

[fitz1]

i think you need to call NASA.

 

[Paul Barker]

You are of course having a laugh, or you are a millionaire or you are extremely thick.

 

[GTO NEMESIS]

You are of course having a laugh, or you are a millionaire or you are extremely thick.

None of the above.
Why would you call me extremely thick?

What a nice welcome to a forum...

 

[fitz1]

500 ltr unvented cyl. maybe two. watch out for water board digging your drive up looking for major leak.hope you aint got a water meter.

 

[simond]

What a lovely shower

Flash as a rat with a gold tooth.

You may want to consider an unvented 300litre cylinder (or greater) with your combi using zone valves on the primaries. Would need a tasty water supply, although it would have to be over 20 litres per min. If this is not available possibly (dare I mention it?) an accumulator might be needed, sized appropriately for your most concerted bout of showering.

You could pump it but you would still need massive storage of hot and cold, and then there would be the noise.......

PS: Is there no TV inside it? So last year.

 

[fitz1]

Didnt Dr Who have something like that.

 

[fitz1]

one or two of the engineers on here i think have something similar in their summer houses , for when they get out of their pools.

 

[Agile]

He called you thick because you dont seem to have researched or obtained professional advice first.

Your shower needs over 20 litres per minute! That would need a combi boiler rated at over 60 kW.

You will need a commercial sized boiler and a new larger gas meter. Possibly an uprated gas supply pipe into your property.

Alternatively you could have a 500 litre cylinder and heat it up overnight from your existing combi and that will give you TWO 10 min showers. Once thats used up it will take an hour to reheat if your boiler is not doing the heating or 3-4 hours if its heating the house as well.

Simple physics!

What kind or work/business are you involved with?

Tony

 

[GTO NEMESIS]

He called you thick because you dont seem to have researched or obtained professional advice first.

I am doing the research now. It is delivered next Friday.
As I have the three important items, IE Gas, Water and space there should not be anything else I need to worry about.

The rest can be solved by advice and suggestions from people like yourself.

What kind or work/business are you involved with?

Hedgefunds - but only because tuning car's wont pay enough.

I knew when I bought it I would need to do some major water supply upgrades hence me asking people on this site and hopefully I will get an answer to my question and know what to purchase.

I am more than capable of fitting it myself but I just don't have time so I want to buy all the bits and get someone to do the job.

Mark

 

[GTO NEMESIS]

Your shower needs over 20 litres per minute! That would need a combi boiler rated at over 60 kW.

You will need a commercial sized boiler and a new larger gas meter. Possibly an uprated gas supply pipe into your property.

I never said I planned on using the combi boiler to supply the shower.
I wanted to know if it was possible to use a combi boiler to fill a hotwater tank/heater tank then pump it to the shower unit instead of using cold water to fill it back up.

Mark

 

[simond]

Well, Mark, in principle you could use the hw cylinder as an accumulator to store water heated by the combi.

But in practice it would be a bad idea for reasons too lengthy to describe here.

Like most domestic solutions, it is best to do something standard, this way you can use normal components and anyone can fix it. You don't want to get involved in a lengthy demarcation dispute with your tardis manufacturer and the plumber. If you attempt something like your suggestion they will laugh at you even if the actual problem is on their unit.

To coin someone else's catchphrase, keep it simple.

 

[Agile]

You have not told us your existing boiler or the size of house or its heating load.

In principle you could have 800 litres of stored cold water in the loft feeding a 500 litre vented hot water cylinder and then pump this to your shower.

Your combi will heat the cylinder.

However its heat output will be devided between the heating and hot water so its best to expect to time the water heating at a different time to the hot water. best time to heat the hot water is during the early hours before the heating is needed.

An "average plumber" will not have a clue about how to do all this though. Many dont even know how to use a combi to heat a cylinder!

Tony

 

[ChrisR]

Not quite sure what you have in mind here.
If you have what you call a standard immersion unit (cylinder) it won't be empty when you start, unless you plan on dumping a lot of cold water every time you want a shower.

An alternative to storing all the water you need might be to use the mains if the local pressure is high enough, with something like a Rinnai
http://www.rinnaiuk.com/product_water_specshd70e.htm which can if necessary go outside.
You'll need a bigger gas meter - no big deal.

It would be more conventional to have a standard system, with maybe 200l of HW, and a 4 bar pump, and get used to short showers.
You could use your combi to heat the hw, or use a separate boiler of about 24kW which would reheat it to 60º in around half an hour . We all shower at about 38-40, so that would give about 15mins showering at 20l/min.
You could run off a standard gas supply/meter , just.

 

[breezer]

I am not a plumber or heating engineer.
It does seem a little bit on the large side, and no one has pointed out that it has two shower heads (I am not counting all the little side jets)

what if seeing as you have now brought it, you only use half of it?
In that perhaps the figures you have quoted are "all at full blast" so by using half you may be ok?