I've finally got the builders in - need to make final choice re
combi-boiler.

House is medium-large semi, present back-boiler system going in the
bin

I want a high flow system so I can have a decent shower

- the builder's recommended a "Alpha CB50"

http://www.alpha-boilers.com/products/CB50.html

This provides a high flow rate - 18l/min @ 60 degrees C until the
internal 60l cylinder is exhausted, then a flow rate of 9-10 l/min @
45 degrees indefinitely

Is this an ideal system for a good shower? I'm concerned that my
showers are going to be short ones at a decent flow rate.

Would I be better going for a combi-boiler without an internal storage
cylinder, but a high flow rate anyway, perhaps the Baxi Combi 130HE?

any advice would be appreciated

John

I want a high flow system so I can have a decent shower

- the builder's recommended a "Alpha CB50"

I know nothing about alpha as a company or their products. However, the
specification of the hot water side looks good and should be enough for your
needs, unless you are planning a panel shower or other such monstrosity. It
isn't condensing, though, so has 80% efficiency, rather than 90% efficiency.
That will add over 10% to your fuel bills compared with a condensing type
(but will save at least as much compared to your old back boiler).

Christian,

On Tue, 30 Mar 2004 17:48:07 +0100, "Christian McArdle"
wrote:

I want a high flow system so I can have a decent shower

- the builder's recommended a "Alpha CB50"

I know nothing about alpha as a company or their products. However, the
specification of the hot water side looks good and should be enough for your
needs, unless you are planning a panel shower or other such monstrosity. It
isn't condensing, though, so has 80% efficiency, rather than 90% efficiency.
That will add over 10% to your fuel bills compared with a condensing type
(but will save at least as much compared to your old back boiler).

But aren't condensing boilers a lot more expensive to buy?

For example:
Vokera Compact 28 £515
Vokera Syntesi 29 £720

It would take a while for it to pay back the difference.

M

John Powell wrote:

I want a high flow system so I can have a decent shower

For an "ordinary" shower then this boiler would be more than adequate.
In fact anything that can do 10L/min or better will be more than you
need for a single shower usually.

- the builder's recommended a "Alpha CB50"

http://www.alpha-boilers.com/products/CB50.html

This provides a high flow rate - 18l/min @ 60 degrees C until the
internal 60l cylinder is exhausted, then a flow rate of 9-10 l/min @
45 degrees indefinitely

Is this an ideal system for a good shower? I'm concerned that my
showers are going to be short ones at a decent flow rate.

They make it quite tricky to find any technical specs on the web site -
but you can download the installation manual which has most of the info
you need. The boiler itself has a direct hot water heat input rating of
33kW - which is toward the larger end, but not the biggest you can buy.
Efficency at 80% is poor (and reduces the real DHW heating capacity to a
real world 26.4kW once its tank is cold). So most of the impressive DHW
performance comes from the 57L tank that is built in.

The main benefit of a storage system like this will tend to be better
performance when filling baths.

Would I be better going for a combi-boiler without an internal storage
cylinder, but a high flow rate anyway, perhaps the Baxi Combi 130HE?

I have no idea what Alpha are like, so will not give any recomendation.
If you want to shop around then I would have thought that it might be
worth looking at condencing combis with a heat input of 30kW or better.
There are a number to choose from.

Price looks OK at just over the grand:-

http://inspiredheating.co.uk/acatalo...D_COMBI_S.html


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"John Rumm" wrote in message
...
John Powell wrote:

I want a high flow system so I can have a decent shower

For an "ordinary" shower then this boiler would be more than adequate.
In fact anything that can do 10L/min or better will be more than you
need for a single shower usually.

- the builder's recommended a "Alpha CB50"

http://www.alpha-boilers.com/products/CB50.html

This provides a high flow rate - 18l/min @ 60 degrees C until the
internal 60l cylinder is exhausted, then a flow rate of 9-10 l/min @
45 degrees indefinitely

Is this an ideal system for a good shower? I'm concerned that my
showers are going to be short ones at a decent flow rate.

They make it quite tricky to find any technical specs on the web site -
but you can download the installation manual which has most of the info
you need. The boiler itself has a direct hot water heat input rating of
33kW - which is toward the larger end, but not the biggest you can buy.
Efficency at 80% is poor (and reduces the real DHW heating capacity to a
real world 26.4kW once its tank is cold). So most of the impressive DHW
performance comes from the 57L tank that is built in.

The main benefit of a storage system like this will tend to be better
performance when filling baths.

Would I be better going for a combi-boiler without an internal storage
cylinder, but a high flow rate anyway, perhaps the Baxi Combi 130HE?

I have no idea what Alpha are like, so will not give any recomendation.
If you want to shop around then I would have thought that it might be
worth looking at condencing combis with a heat input of 30kW or better.
There are a number to choose from.

Price looks OK at just over the grand:-

http://inspiredheating.co.uk/acatalo...D_COMBI_S.html

Just over 1K? Then here is what I suggested in another thread:
Good simple combi's are Ferroli Modena and Worcester Bosch Junior at around
11 to 12 litres/min. Great for frequent showers and a simple designs with
no 3-ways valves.

For high flowrates it is cost effective to use two Juniors and combine the
outlets. Worcester will supply a drawing on how to do it. Two Juniors are
available for around £1000 to 1100 depending on what sized units you buy.
They have 24 and 28 kW you could use two 24kW or two 28 kW combi's or one of
each. That is cheaper than the Worcester HighFlow 18 litres/min floor
mounted combi and can deliver about 21.5 litres/min and never run out
of hot water.

Have one combi do the downstairs heating on its own programmer/timer and one
do upstairs. Natural zoning, so you don't have to heat upstairs when you
are not up there saving fuel. The running cost will approx the same as a
condensing boiler heating the whole house. No external zone valves either,
and simple wiring up too. Also if one goes down you will have another combi
to give some heat in the house and DHW too. Combine the outlets for DHW and
all the baths you want very quickly and no waiting. It will do two showers
no problem at all. A win, win, situation.

IMM wrote:

to give some heat in the house and DHW too. Combine the outlets for DHW and
all the baths you want very quickly and no waiting. It will do two showers
no problem at all. A win, win, situation.

While there are attractions to a two combi system, to describe it as a
win win situation would be a best misleading.

One factor you always seem to ignore when presenting this argument is
the cost of installation. While the cost of the boilers may not work out
costing much more than the cost of a larger boiler, it is going to cost
getting on for double the amount to install. In many cases the cost of
installing is significantly more than the cost of the boiler.

If you go for two boilers on different floors, then you also need to
find a place to install the second - in many properties this is not a
trivial task. You are going to be paying to have two boilers serviced
annualy as well.

There are advantages and also disadvantages of any setup - a win / loose
situation.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"John Rumm" wrote in message
...
IMM wrote:

to give some heat in the house and DHW too.
Combine the outlets for DHW and
all the baths you want very quickly and no
waiting. It will do two showers
no problem at all. A win, win, situation.

While there are attractions to a two
combi system, to describe it as a
win win situation would be a best misleading.

One factor you always seem to ignore
when presenting this argument is
the cost of installation.

That is the point, it is cheap to install, with no zone valves, etc.

While the cost of the boilers may not work out
costing much more than the cost of a larger boiler,
it is going to cost getting on for double the
amount to install.

Absolute nonsense. If anything it will be CHEAPER to install. In an
existing system, separating the system to upstairs and down may in some case
prove problematic, but in most system the upstairs and downstairs are two
separate loops.

This is a TWO zone setup. If you wanted the same from a single boiler it
would be more complicated and the same applies to the pipework runs pof
both.

In many cases the cost of
installing is significantly more than
the cost of the boiler.

Absolute nonsense !!!!!

If you go for two boilers on
different floors, then you also need to
find a place to install the second - in
many properties this is not a
trivial task.

You can put them both together One,or both, can go at the back of the
airing cupboard, still releasing tons of space by the redundant cylinder.

You are going to be paying to have
two boilers serviced
annualy as well.

You can always get a deal with two boiers when they next to each other.

There are advantages and also disadvantages
of any setup - a win / loose situation.

The two combi setup, has few disadvantages and the only one you picked up on
is the increased cost of servicing, which is not a great amount. The Junior
doesn't even have a 3-way valve making it more reliable. Every other point
you raised was wrong. Two Worcester-Bosch Juniors cost from under £100 to
around £1100. Giving approx 21.3 litres/minute. Go and find a single
boiler that can do that at that price. The ECO-Hometec, although a
condensing boiler, can go to 22 litres/min, but at just under 2K for it.
And when it is down no heat or hot water, unike the two combi setup.

On Wed, 31 Mar 2004 17:09:40 +0100, "IMM" wrote:


"John Rumm" wrote in message
.. .
IMM wrote:


One factor you always seem to ignore
when presenting this argument is
the cost of installation.

That is the point, it is cheap to install, with no zone valves, etc.

Zone valves are hardly expensive, are they?


While the cost of the boilers may not work out
costing much more than the cost of a larger boiler,
it is going to cost getting on for double the
amount to install.

Absolute nonsense. If anything it will be CHEAPER to install. In an
existing system, separating the system to upstairs and down may in some case
prove problematic, but in most system the upstairs and downstairs are two
separate loops.

Really? This rather depends on whether the pipes run under the
ground floor, doesn't it?



This is a TWO zone setup. If you wanted the same from a single boiler it
would be more complicated and the same applies to the pipework runs pof
both.

In many cases the cost of
installing is significantly more than
the cost of the boiler.

Absolute nonsense !!!!!

Labour costs in what has become a premium trade are not cheap......




If you go for two boilers on
different floors, then you also need to
find a place to install the second - in
many properties this is not a
trivial task.

You can put them both together One,or both, can go at the back of the
airing cupboard, still releasing tons of space by the redundant cylinder.

.... needing a gas supply to be run there.....


You are going to be paying to have
two boilers serviced
annualy as well.

You can always get a deal with two boiers when they next to each other.

Hmmm......


There are advantages and also disadvantages
of any setup - a win / loose situation.

The two combi setup, has few disadvantages and the only one you picked up on
is the increased cost of servicing, which is not a great amount.

Only double, but that's not a lot, I suppose.

The Junior
doesn't even have a 3-way valve making it more reliable. Every other point
you raised was wrong. Two Worcester-Bosch Juniors cost from under £100 to
around £1100. Giving approx 21.3 litres/minute. Go and find a single
boiler that can do that at that price. The ECO-Hometec, although a
condensing boiler, can go to 22 litres/min, but at just under 2K for it.
And when it is down no heat or hot water, unike the two combi setup.


If any boiler is so bad that it needs a second unit as a backup in a
domestic situation, then it doesn't deserve house room.

An immersion heater in a cylinder is a more useful solution in the
event of boiler failure since a totally separate energy source is used
as well.


..andy

To email, substitute .nospam with .gl

IMM wrote:

I think I am beginning to understand why my spell checker always wants
to change IMM to DIM....

That is the point, it is cheap to install, with no zone valves, etc.

OK I will take it nice and slowly for you, see if you can keep up (feel
free to move your lips as you read if it helps)

How do you work out the cost of installing a boiler?

Well there are two parts to the equation: parts and labour.

What parts do we need? Some copper pipe + fittings, solder, flux, and an
assortment of valves etc depending on the type of install we are doing.
Factor in a bit of wear on your core bore when drilling the flue, and
some gas for your blowtorch, petrol etc. and you have a couple of
hundred perhaps.

Now lets assume it is a pretty straight forward operation and one man
gets it done in a day. That will be 8 hours at anything from 70 quid
per hour upwards - so including the parts that would be 760 or more.

Of course in the OPs situation he was looking to replace a back boiler -
that is not going to be so quick and easy. Parts won't cost much more -
labour will.

What does your boiler cost? Comparable to the parts + labour charge I
would have thought. So my statement that the cost of installing the
boiler is going to cost about the same as the boiler is I would say fair.

Now lets say you want ot install two of them. Cost of parts will may be
similar maybe less or perhaps more if there is much new pipework to
install. Draining down only needs to be done once so you save a little
there. Pretty much everything else is going to take the same amount of
time again. Hence getting on for double the labour costs.

Absolute nonsense. If anything it will be CHEAPER to install. In an

Perhaps in the IMM time vortex one man can install two boilers in half
time time it takes the same man to install one...

Hmm yup see your logic there. How is K9 these days?

existing system, separating the system to upstairs and down may in some case
prove problematic, but in most system the upstairs and downstairs are two
separate loops.

As a generalisation that probably does not work.... most modern houses
with solid floors downstairs will be plumbed as one loop under the first
floor. Older properties with susspended floors may have two loops. Not
really relevant either way since we are talking about retrofitting a new
boiler to an existing heating system.

This is a TWO zone setup. If you wanted the same from a single boiler it
would be more complicated and the same applies to the pipework runs pof
both.

So you are saying: It would be more complicated for a single boiler and
the same applies to both?

Errrm subtitles anyone?

In many cases the cost of
installing is significantly more than
the cost of the boiler.


Absolute nonsense !!!!!

A bit out of touch I see...

If you go for two boilers on
different floors, then you also need to
find a place to install the second - in
many properties this is not a
trivial task.


You can put them both together One,or both, can go at the back of the
airing cupboard, still releasing tons of space by the redundant cylinder.

Assuming the cylinder was in the airing cupboard and not the loft... If
it is in an airing cupboard are you including the cost of providing
alternative heating for the cupboard since you are not going to get much
out of the casework of a decent condensing boiler?

Perhaps the OP would be better off installing a plain system boiler,
keeping the cylinder, and adding a shower pump...

You are going to be paying to have
two boilers serviced
annualy as well.


You can always get a deal with two boiers when they next to each other.

"OK mate I will only charge you twice the price to service them - five
quid discount since I will use less petrol..." (plus 20% hike to account
for the customer being a soft enough touch to fall for the two boilers gag)

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"IMM" wrote in message
...

"John Rumm" wrote in message
...
John Powell wrote:

I want a high flow system so I can have a decent shower

For an "ordinary" shower then this boiler would be more than adequate.
In fact anything that can do 10L/min or better will be more than you
need for a single shower usually.

- the builder's recommended a "Alpha CB50"

http://www.alpha-boilers.com/products/CB50.html

This provides a high flow rate - 18l/min @ 60 degrees C until the
internal 60l cylinder is exhausted, then a flow rate of 9-10 l/min @
45 degrees indefinitely

Is this an ideal system for a good shower? I'm concerned that my
showers are going to be short ones at a decent flow rate.

They make it quite tricky to find any technical specs on the web site -
but you can download the installation manual which has most of the info
you need. The boiler itself has a direct hot water heat input rating of
33kW - which is toward the larger end, but not the biggest you can buy.
Efficency at 80% is poor (and reduces the real DHW heating capacity to a
real world 26.4kW once its tank is cold). So most of the impressive DHW
performance comes from the 57L tank that is built in.

The main benefit of a storage system like this will tend to be better
performance when filling baths.

Would I be better going for a combi-boiler without an internal storage
cylinder, but a high flow rate anyway, perhaps the Baxi Combi 130HE?

I have no idea what Alpha are like, so will not give any recomendation.
If you want to shop around then I would have thought that it might be
worth looking at condencing combis with a heat input of 30kW or better.
There are a number to choose from.

Price looks OK at just over the grand:-

http://inspiredheating.co.uk/acatalo...D_COMBI_S.html

£783 + VAT = £920 from T&P
http://tinyurl.com/2uc5x

IMM wrote:

?783 + VAT = ?920 from T&P
http://tinyurl.com/2uc5x

Don't forget the flue at 40 quid...


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote in message .. .
John Powell wrote:

I want a high flow system so I can have a decent shower

For an "ordinary" shower then this boiler would be more than adequate.
snip

One potential problem for me is the apparent low flow rate into the
house from the mains

I did a check at the nearest cold tap to the water inlet, ( the cold
water is at mains pressure) - I filled a 2 litre jug and timed it

it came out at about 15l/min

would that change the optimum choice of boiler?

thanks

John

"John Powell" wrote in message
om...
John Rumm wrote in message
.. .
John Powell wrote:

I want a high flow system so I can have a decent shower

For an "ordinary" shower then this
boiler would be more than adequate.
snip

One potential problem for me is the
apparent low flow rate into the
house from the mains

I did a check at the nearest cold tap
to the water inlet, ( the cold
water is at mains pressure) - I filled a
2 litre jug and timed it

it came out at about 15l/min

would that change the optimum choice of boiler?

Yes. No more than 15 litres/min. This will still give you a decent high
pressure shower. Is the stop cock fully open? Is the cock in the street
fully open? Do the neighbours have similar flowrates? If you mainly have
showers and can wait a few more minutes to fill a bath on the odd occasions
you have one, then all is fine. It may be worth looking into replacing the
mains pipe to larger 25mm bore back to the road. This is well worth
considering. Once done it is fine for ever. If you want fast bath fills
frequently and you don't want to upgrade your mains pipe, then you will have
to go tank/cylinder

If you go tank cylinder then use a Fortic type of tank/cylinder combination
unit (this is all one insulated unit and can go in the loft) with an
integral quick recovery coil. Have a combi (Worcester Junior is having good
reports of late; and simple) heat the cylinder as per usual, but with a
priority system of DHW. have the shower only through the water section of
the combi giving high pressure showers and all other hot outlets from the
tank/cylinder. You only did high pressure at the shower, all the rest need
volume not pressure.

On Wed, 31 Mar 2004 09:13:56 +0100, "IMM" wrote:

If you go tank cylinder then use a Fortic type of tank/cylinder combination
unit (this is all one insulated unit and can go in the loft) with an
integral quick recovery coil. Have a combi (Worcester Junior is having good
reports of late; and simple) heat the cylinder as per usual, but with a
priority system of DHW. have the shower only through the water section of
the combi giving high pressure showers and all other hot outlets from the
tank/cylinder. You only did high pressure at the shower, all the rest need
volume not pressure.

How do you get a combi boiler to heat a cylinder?

John Powell wrote:

One potential problem for me is the apparent low flow rate into the
house from the mains

I did a check at the nearest cold tap to the water inlet, ( the cold
water is at mains pressure) - I filled a 2 litre jug and timed it

it came out at about 15l/min

would that change the optimum choice of boiler?

I had this concern myself since we have a poor (ish) mains feed. I found
I actually got the best flow rate at the cold bath tap however (the
kitchen tap is a monobloc mixer with microbore feed, and was giving a
misleading impression that the feed was capable of 5 or more l/min less
than was actually the case). So it might be worth repeating the test at
another tap if possible. Use a larger container and time say 10 litres
to get a more accurate picture.

If the limit really is 15 l/min then you have three choices:-

1) live with it, since it is plenty good enough for a shower, and is not
going to restrict the performance of any combi below 38kW (i.e. quite large)

2) Upgrade the mains feed

3) Fit a mains pressure unvented cylinder, and heat it like you would a
conventional hot water cylinder.

Option 2 is worth doing if you are looking for a very high end combi
system (or multiple combis).

Option 3 will outperform the combi systems for things like bath filling
but cost as much or more than IMM's "a boiler for every room of the
house" scheme.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"John Rumm" wrote in message
...
John Powell wrote:

One potential problem for me is the apparent low flow rate into the
house from the mains

I did a check at the nearest cold tap to the water inlet, ( the cold
water is at mains pressure) - I filled a 2 litre jug and timed it

it came out at about 15l/min

would that change the optimum choice of boiler?

I had this concern myself since we have a poor (ish) mains feed. I found
I actually got the best flow rate at the cold bath tap however (the
kitchen tap is a monobloc mixer with microbore feed, and was giving a
misleading impression that the feed was capable of 5 or more l/min less
than was actually the case). So it might be worth repeating the test at
another tap if possible. Use a larger container and time say 10 litres
to get a more accurate picture.

If the limit really is 15 l/min then you have three choices:-

1) live with it, since it is plenty good enough for a shower, and is not
going to restrict the performance of any combi below 38kW (i.e. quite
large)

2) Upgrade the mains feed

3) Fit a mains pressure unvented cylinder, and heat it like you would a
conventional hot water cylinder.

Option 2 is worth doing if you are looking for a very high end combi
system (or multiple combis).

Option 3 will outperform the combi
systems for things like bath filling

Not so. The Alpha CB50 combi will perform just the same. In fact it has an
unvented cyoidner inside it, and will revert to a,ow flowrate when the
cyinder is empty, which should be very rare in anormal one bathroom house.

but cost as much or more than IMM's
"a boiler for every room of the
house" scheme.

Nothing like a know-it-all amateur is there.

(John Powell) wrote in message . com...

[SNIP]
Would I be better going for a combi-boiler without an internal storage
cylinder, but a high flow rate anyway, perhaps the Baxi Combi 130HE?

We have a Baxi 130HE. Great boiler technically, shame the same cannot
be said about their service engineers (or customer service for that
matter!).
I would not recommend buying a Baxi product purely for this reason.

Our boiler had a simple fault, the valve which is supposed to stop
flow to the central heating when hot water is drawn never operated.
None of the engineers (including a 'senior' one) believed there was a
fault, coming up with all sorts of vague "reasons" for the poor
performance. One engineer replaced the control board (thinking, with
no evidence, that this would cure the problem), then failed to believe
that it had to be set up to use the intellistat - he actually insisted
(without checking) that it didn't need setting up, and left. Two
hours later, we had a cold house and I had to dig out the manual and
do it myself. This is on top of two week waiting lists for service
appointments, and one missed appointment (with no notification).
Eventually (after six months of high gas bills and poor hot water),
the fault became clear as the warmer weather started and we had a red
hot house everytime someone had a shower - they replaced the valve
(after we had presented them with clear evidence of the fault, no
investigation on their part) - no problems since...

Customer service never responded to our letter of complaint (or our
installer's independent letter).

Good boiler - bad service - don't go there!