Hi,

I'm moving into a bungalow that has a 7 year old back boiler and tank
working flawlessley. We will be adding 2 showers, 1 bath, 5 radiators
and a towel rail once extension is completed.

To enable staging of the work (we will be living in the house while
doing the work) I was thinking of keeping the back boiler and adding a
separate combi-boiler.

The question is - what do i run off the combi and what off the existing
back boiler?

Philip

wrote in message
ups.com...
Hi,

I'm moving into a bungalow that has a 7 year old back boiler and tank
working flawlessley. We will be adding 2 showers, 1 bath, 5 radiators
and a towel rail once extension is completed.

To enable staging of the work (we will be living in the house while
doing the work) I was thinking of keeping the back boiler and adding a
separate combi-boiler.

The question is - what do i run off the combi and what off the existing
back boiler?

Philip

electric showers, heating off combi, water tank off back boiler.

In article . com,
wrote:
I'm moving into a bungalow that has a 7 year old back boiler and tank
working flawlessley. We will be adding 2 showers, 1 bath, 5 radiators
and a towel rail once extension is completed.

To enable staging of the work (we will be living in the house while
doing the work) I was thinking of keeping the back boiler and adding a
separate combi-boiler.

The question is - what do i run off the combi and what off the existing
back boiler?

The storage system is best where you want high flow - filling a bath or a
powerful shower. The combi for low flow applications like kitchen sink and
bathroom basin, and possibly a shower.

--
*I am a nobody, and nobody is perfect; therefore I am perfect*

Dave Plowman London SW
To e-mail, change noise into sound.

Jason wrote:

The question is - what do i run off the combi and what off the existing
back boiler?

electric showers, heating off combi, water tank off back boiler.

What is the point of installing a combi if it is to be connected to
heating only ?

"Dave Plowman (News)" wrote in message
...
In article . com,
wrote:
I'm moving into a bungalow that has a 7 year old back boiler and tank
working flawlessley. We will be adding 2 showers, 1 bath, 5 radiators
and a towel rail once extension is completed.

To enable staging of the work (we will be living in the house while
doing the work) I was thinking of keeping the back boiler and adding a
separate combi-boiler.

The question is - what do i run off the combi and what off the existing
back boiler?

The storage system is best where you want high flow - filling a bath or a
powerful shower. The combi for low flow applications like kitchen sink and
bathroom basin, and possibly a shower.

IMHO the bathroom basin is the very worst application - unless it is very
close the delay in the presentation of hot water is really frustrating.
Conversely I would put the bath towards the top because the filling takes so
long the initial delay is not that relevant and at the end of the process
the combi can still deliver piping hot water. Of course I partly damn with
faint praise except for the first point.

Jim A

In article ,
Jim Alexander wrote:
The storage system is best where you want high flow - filling a bath
or a powerful shower. The combi for low flow applications like kitchen
sink and bathroom basin, and possibly a shower.

IMHO the bathroom basin is the very worst application - unless it is
very close the delay in the presentation of hot water is really
frustrating. Conversely I would put the bath towards the top because
the filling takes so long the initial delay is not that relevant and at
the end of the process the combi can still deliver piping hot water.
Of course I partly damn with faint praise except for the first point.

Of course it depends on where the combi is situated. Same with a storage
tank. If you want truly instant hot water everywhere I suppose you'd need
a storage tank at every outlet, or a circulating circuit from a storage
tank. Can't be done from a combi.

--
*Depression is merely anger without enthusiasm *

Dave Plowman London SW
To e-mail, change noise into sound.

Of course I partly damn with faint praise except for the first point.

I'm ignoring the electic shower idea - I have just moved from a combi
shower to a 9kW electic and it is a pale imitation in my opinion...

so can i get this clear it is suggested to:

a) run the hot water to showers from the back boiler heated tank - i
would need to put in pressure balancing tanks for the cold and probably
a pump for each shower. It's a mid sized tank apparently.

b) run the hot water to the baths from the back boiler heated tank

c) run the CH from the back boiler heated tank

It seems you all favour the storage tank!

This would be swell (and cheaper probably) - but i hate running out of
water, and I'm not sure the old boiler BTU's will be up to the job of 2
bathrooms and 5 extra radiators. Also - we won't be very efficient.

Its still a bit of a dilema - what's the cheapest option?

wrote in message
oups.com...


Of course I partly damn with faint praise except for the first point.

I'm ignoring the electic shower idea - I have just moved from a combi
shower to a 9kW electic and it is a pale imitation in my opinion...

so can i get this clear it is suggested to:

a) run the hot water to showers from the back boiler heated tank - i
would need to put in pressure balancing tanks for the cold and probably
a pump for each shower. It's a mid sized tank apparently.

b) run the hot water to the baths from the back boiler heated tank

c) run the CH from the back boiler heated tank

It seems you all favour the storage tank!

This would be swell (and cheaper probably) - but i hate running out of
water, and I'm not sure the old boiler BTU's will be up to the job of 2
bathrooms and 5 extra radiators. Also - we won't be very efficient.

Its still a bit of a dilema - what's the cheapest option?

Definately not to have two boilers.

Jim A

wrote in message
ups.com...
Hi,

I'm moving into a bungalow that has a 7 year old back boiler and tank
working flawlessley. We will be adding 2 showers, 1 bath, 5 radiators
and a towel rail once extension is completed.

To enable staging of the work (we will be living in the house while
doing the work) I was thinking of keeping the back boiler and adding a
separate combi-boiler.

The question is - what do i run off the combi and what off the existing
back boiler?

Philip

It seems too complicated to have two boilers - been there - and
unnecessarily expensive for maintenance and potentially difficult to control
depending on the systemdesign. Why not aim to switch from the back boiler
to a modern new boiler at some time during the work. However, why do you
need a new boiler at all - is the back boiler not up uprateable to the new
heat output? If you do decide to keep both then you need to think of peak
heating load. Would you sacrifice heat output to your radiators to divert it
into the hot water? How will you control the system? Could you end up
running one boiler just to heat one room some of the time?

If you go for a combi size it for the hot water supply rate that you want
which could be more than you need for heating. You could consider a
pressurised hot water storage system so that you get mains pressure hot
water in your showers without the need for pumps etc. Much beter than a 9kW
electric model.