Help with showers and combi-boiler
Discussion
i have a combi boiler 24kW (one thats 15+ years old), in a semi det. with 1 bathroom + mixer shower. I like my showers powerful and have no quarms with our shower. The only thing that you notice is when someone turns the tap on downstairs, the tempurature fluctuates which i believe you wouldn't get with a tank etc.
+ to add, i would have a combi over a tank system anyday, as personally i like long showers + with the missus aswell, theres no shortage of hot water.
+ to add, i would have a combi over a tank system anyday, as personally i like long showers + with the missus aswell, theres no shortage of hot water.
The bigger KW output of the combination boiler, the better flow of hot water that can be achieved. But this is obviously capped by the flow of your incoming mains water.
Pressure will also be dictated by your incoming main.
With a low pressure setup, you put a wracking great shower pump into play. 3 bar makes for a lovely shower.
Or, incoming main dependant again, an unvented setup, cylinder or combination setup. Unvented cylinder would be my port of call.
All depends on room, money, etc.
Pressure will also be dictated by your incoming main.
With a low pressure setup, you put a wracking great shower pump into play. 3 bar makes for a lovely shower.
Or, incoming main dependant again, an unvented setup, cylinder or combination setup. Unvented cylinder would be my port of call.
All depends on room, money, etc.
Rickyy said:
Make one of the showers an electric item! You'll thank me when the boiler breaks down!
Been advised of this too but were choosing to take the risk......Thanks for all the comments and help, the water pressure is not too bad so i would be better with a higher KW output on the boiler......
That boiler (24i??) will give you a very poor flow rate of around 9 litres a minute, you need something of at least 13 litres per minute... Like this
http://www.worcester-bosch.co.uk/boilers/gas-boile... (hopefully link will work as using mobile)
http://www.worcester-bosch.co.uk/boilers/gas-boile... (hopefully link will work as using mobile)
Edited by Martyn D on Monday 5th March 08:00
ROB_GTR said:
Just found out the combi-boiler the builder has in mind is a Worcester green star 18KW......
As the KW seems rather low would you suggest upgrading and if so what would you recommend?
Cheers
Worcester don't make an 18kw combi,their smallest is a 24i junior(24kw) which I certainly wouldn't recommend for 2 showers.As the KW seems rather low would you suggest upgrading and if so what would you recommend?
Cheers
Edited by vanman on Monday 5th March 08:04
vanman said:
ROB_GTR said:
Just found out the combi-boiler the builder has in mind is a Worcester green star 18KW......
As the KW seems rather low would you suggest upgrading and if so what would you recommend?
Cheers
Worcester don't make an 18kw combi,their smallest t is a 24i junior(24kw) which I certainly wouldn't recommend for 2 showers.As the KW seems rather low would you suggest upgrading and if so what would you recommend?
Cheers
So what would everyone recommend as i need to alert the biulder sharpish if this will not be good enough.....
Cheers
ROB_GTR said:
Oh don't they? http://www.discountedheating.co.uk/shop/acatalog/W...
So what would everyone recommend as i need to alert the biulder sharpish if this will not be good enough.....
Cheers
The Ri is a heat only boiler,it isn't a combi.So what would everyone recommend as i need to alert the biulder sharpish if this will not be good enough.....
Cheers
What are your requirements and expectations?
What heat input does the building require?
What Incoming flow rate on the mains?
what site limitations are there?
What options are available when the above have been taken into account?
Or you could just stick in a boiler that the builder has in the back of his garage.
What heat input does the building require?
What Incoming flow rate on the mains?
what site limitations are there?
What options are available when the above have been taken into account?
Or you could just stick in a boiler that the builder has in the back of his garage.
dirkgently said:
What are your requirements and expectations?
What heat input does the building require?
What Incoming flow rate on the mains?
what site limitations are there?
What options are available when the above have been taken into account?
Or you could just stick in a boiler that the builder has in the back of his garage.
Its a self build and the plumber will be doing 1st fix next week.What heat input does the building require?
What Incoming flow rate on the mains?
what site limitations are there?
What options are available when the above have been taken into account?
Or you could just stick in a boiler that the builder has in the back of his garage.
The house is 5 bedroom with 1 main bathroom (1 bath & 1 shower), en-suite (1 shower) downstairs toilet.....
My expectations is to be able to run 2 showers at the same time without loss of hot water or scalding etc.
I also want a good powerful shower and not a feeble dribble.
We have underfloor heating downstairs and radiators up.
My builder has just said the plan was for a Worcester green star 18KW so sorry for the above mistake but i just searched for a "Worcester green star 18KW"
What would be the best option and what would you suggest?
WB are good boilers and come (I think) with a five year guarantee so good choice. I fitted a Potterton Heatmax 28 last autumn and it's OK for a shower but not earth shattering. No problem with a 28 but I wouldn't want anything less powerful. The 18 or 24 isn't going to make you a happy, or very wet, bunny.
IMHO stick with the brand, just up the KW. Difference in price is a couple fo hundred quid at most, not much in the scheme of things.
http://www.plumbcenter.co.uk/en/heating/domestic-b...
And for flow rates etc;
http://www.worcester-bosch.co.uk/homeowner/boilers...
IMHO stick with the brand, just up the KW. Difference in price is a couple fo hundred quid at most, not much in the scheme of things.
http://www.plumbcenter.co.uk/en/heating/domestic-b...
And for flow rates etc;
http://www.worcester-bosch.co.uk/homeowner/boilers...
ColinM50 said:
WB are good boilers and come (I think) with a five year guarantee so good choice. I fitted a Potterton Heatmax 28 last autumn and it's OK for a shower but not earth shattering. No problem with a 28 but I wouldn't want anything less powerful. The 18 or 24 isn't going to make you a happy, or very wet, bunny.
IMHO stick with the brand, just up the KW. Difference in price is a couple fo hundred quid at most, not much in the scheme of things.
http://www.plumbcenter.co.uk/en/heating/domestic-b...
And for flow rates etc;
http://www.worcester-bosch.co.uk/homeowner/boilers...
If you only have 10lpm coming in to the property it is of no consequence how many lpm the boiler can give.IMHO stick with the brand, just up the KW. Difference in price is a couple fo hundred quid at most, not much in the scheme of things.
http://www.plumbcenter.co.uk/en/heating/domestic-b...
And for flow rates etc;
http://www.worcester-bosch.co.uk/homeowner/boilers...
ColinM50 said:
WB are good boilers and come (I think) with a five year guarantee so good choice. I fitted a Potterton Heatmax 28 last autumn and it's OK for a shower but not earth shattering. No problem with a 28 but I wouldn't want anything less powerful. The 18 or 24 isn't going to make you a happy, or very wet, bunny.
IMHO stick with the brand, just up the KW. Difference in price is a couple fo hundred quid at most, not much in the scheme of things.
http://www.plumbcenter.co.uk/en/heating/domestic-b...
And for flow rates etc;
http://www.worcester-bosch.co.uk/homeowner/boilers...
Bear in mind those flow rates are only @ 35 degree temperature rise too,so when the incoming water temp is 5 degrees in winter then at the specified flow rate you'll have hot water at 40 degrees which is not hot enough in my opinion.IMHO stick with the brand, just up the KW. Difference in price is a couple fo hundred quid at most, not much in the scheme of things.
http://www.plumbcenter.co.uk/en/heating/domestic-b...
And for flow rates etc;
http://www.worcester-bosch.co.uk/homeowner/boilers...
On the Worcester site the specified flow rate for a 24i junior is 9.8 lpm,however to reach a decent temperature you'll be looking at 8lpm.
I wouldn't recommend a combi in your situation but if thats what you've decided on then providing you've got enough mains pressure/flow then your best option is a 42 cdi,bear in mind with this though you'll need an adequately sized gas pipe to cope with the boiler running at maximum rate to give the correct working pressure at the boiler(I don't see many 42cdi's that have sufficiently sized gas supplies)
Right..... bit of an update and better news than i originally thought.
Just spoken to the plumber and its not a combi were having it is in fact a system boiler and unvented cylinder system that will (apparently) be more than enough for what we need although it is still the Worcester Bosch greenstar 18 that will be used......
He says it will give easily enough hot water for 2 / 3 showers at mains pressure and run the CH with ease
Is this sounding better?
Just spoken to the plumber and its not a combi were having it is in fact a system boiler and unvented cylinder system that will (apparently) be more than enough for what we need although it is still the Worcester Bosch greenstar 18 that will be used......
He says it will give easily enough hot water for 2 / 3 showers at mains pressure and run the CH with ease
Is this sounding better?
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