Hi,

Can anyone recommend a boiler that is suitable for fitting in a loft
space? We (will) have 4 bedrooms and two bathrooms (both with baths
and showers) so the boiler must handle that.

The only boilers I can find that have this capacity are not suitable
for loft installation (e.g. Worcester Bosch Highflow 400). I am not
convinced (yet) that a combi will be suitable.

TIA, M

wrote in message
...
Hi,

Can anyone recommend a boiler that is suitable for fitting in a loft
space? We (will) have 4 bedrooms and two bathrooms (both with baths
and showers) so the boiler must handle that.

The only boilers I can find that have this capacity are not suitable
for loft installation (e.g. Worcester Bosch Highflow 400). I am not
convinced (yet) that a combi will be suitable.

A high flow combi will be suitable if you know its limitations. Would both
baths be used at the same time? probably not. The Highflow can go in a
loft., if you can get it up there.

Try a Potterton Powermax, floor mounted, they have a two bathroom 150 litre
jobs. A one box solution. It breaks down for ease of handling, so easy to
get into the loft.
http://www.potterton.co.uk/products/...owermaxHE.html

Any sealed flue boiler can go in the loft as long as you can get it up
there. There needs to a solid walk area, ladder up there, lighting and a
bar around the hatch which can be wood screed to the rafters.

Or you could fit two Worcester-Bosch Junior combi's up there. One doing one
bathroom, one doing the other, one doing the utility room one doing the
kitchen. One doing upstairs heating with a programmer/stat, one doing the
down with another programmer/stat. Upstairs can be off when down is on
saving on bills. Divide and rule, one shower will not affect the other
provided the water supply is fine. If one is down you always have hot water
and heating in the house.

Very cost effective, simple, effective and certainly worth considering.

On Tue, 13 Jul 2004 12:07:29 +0100, "IMM" wrote:


wrote in message
.. .
Hi,

Can anyone recommend a boiler that is suitable for fitting in a loft
space? We (will) have 4 bedrooms and two bathrooms (both with baths
and showers) so the boiler must handle that.

The only boilers I can find that have this capacity are not suitable
for loft installation (e.g. Worcester Bosch Highflow 400). I am not
convinced (yet) that a combi will be suitable.

A high flow combi will be suitable if you know its limitations. Would both
baths be used at the same time? probably not. The Highflow can go in a
loft., if you can get it up there.

Try a Potterton Powermax, floor mounted, they have a two bathroom 150 litre
jobs. A one box solution. It breaks down for ease of handling, so easy to
get into the loft.
http://www.potterton.co.uk/products/...owermaxHE.html

One needs to check that there is a suitable way of supporting this
kind of weight in the loft.



Any sealed flue boiler can go in the loft as long as you can get it up
there. There needs to a solid walk area, ladder up there, lighting and a
bar around the hatch which can be wood screed to the rafters.

Or you could fit two Worcester-Bosch Junior combi's up there. One doing one
bathroom, one doing the other, one doing the utility room one doing the
kitchen.

So that's four in total now. Do you have a special offer on them
this week?


One doing upstairs heating with a programmer/stat, one doing the
down with another programmer/stat. Upstairs can be off when down is on
saving on bills. Divide and rule, one shower will not affect the other
provided the water supply is fine. If one is down you always have hot water
and heating in the house.

Very cost effective, simple, effective and certainly worth considering.


..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Tue, 13 Jul 2004 12:07:29 +0100, "IMM" wrote:


wrote in message
.. .
Hi,

Can anyone recommend a boiler that is suitable for fitting in a loft
space? We (will) have 4 bedrooms and two bathrooms (both with baths
and showers) so the boiler must handle that.

The only boilers I can find that have this capacity are not suitable
for loft installation (e.g. Worcester Bosch Highflow 400). I am not
convinced (yet) that a combi will be suitable.

A high flow combi will be suitable if you know its limitations. Would
both
baths be used at the same time? probably not. The Highflow can go in a
loft., if you can get it up there.

Try a Potterton Powermax, floor mounted, they have a two bathroom 150
litre
jobs. A one box solution. It breaks down for ease of handling, so easy
to
get into the loft.
http://www.potterton.co.uk/products/...owermaxHE.html

One needs to check that there is a suitable way of supporting this
kind of weight in the loft.



Any sealed flue boiler can go in the loft as long as you can get it up
there. There needs to a solid walk area, ladder up there, lighting and a
bar around the hatch which can be wood screed to the rafters.

Or you could fit two Worcester-Bosch Junior combi's up there. One doing
one
bathroom, one doing the other, one doing the utility room one doing the
kitchen.

So that's four in total now.

It is?

On Tue, 13 Jul 2004 21:48:19 +0100, "IMM" wrote:



Or you could fit two Worcester-Bosch Junior combi's up there. One doing
one
bathroom, one doing the other, one doing the utility room one doing the
kitchen.

So that's four in total now.

It is?


Mmm.

I was thinking that Worcester-Bosch have "discovered" you and put you
on commission, although one does have to say that some men are
discovered and others are found out.....


..andy

To email, substitute .nospam with .gl

On Tue, 13 Jul 2004 12:07:29 +0100, "IMM" wrote:

[I can't post on my normal server at the moment so am posting via
google]

wrote in message
.. .
Hi,

Can anyone recommend a boiler that is suitable for fitting in a
loft
space? We (will) have 4 bedrooms and two bathrooms (both with
baths
and showers) so the boiler must handle that.

The only boilers I can find that have this capacity are not
suitable
for loft installation (e.g. Worcester Bosch Highflow 400). I am
not
convinced (yet) that a combi will be suitable.

A high flow combi will be suitable if you know its limitations.
Would both
baths be used at the same time? probably not. The Highflow can go
in a
loft., if you can get it up there.

I doubt both baths would be used at the same time very often. But I'm
sure two showers or a hot tap and shower would be used simultaneously.
I do like my bath to fill quickly.

I looked at the W-B web site and I am confused about the possibility
of siting the Highflow in the loft. Although they do a balanced flue
option they still state ventilation requirements to BS 5440:Part 2
(high and low vents).

Try a Potterton Powermax, floor mounted, they have a two bathroom 150
litre
jobs. A one box solution. It breaks down for ease of handling, so
easy to
get into the loft.
http://www.potterton.co.uk/products/...owermaxHE.html

At more than £1700 for the boiler alone (150l) I think that's a bit
too expensive for me. Again I am uncertain of the ventilation
requirements for this boiler.

Any sealed flue boiler can go in the loft as long as you can get it
up
there. There needs to a solid walk area, ladder up there, lighting
and a
bar around the hatch which can be wood screed to the rafters.

I also wonder about the boiler controls. I don't want to have to go
in the loft every time I need to change the boiler settings. Do any
boilers have full remote controls?

Or you could fit two Worcester-Bosch Junior combi's up there. One
doing one
bathroom, one doing the other, one doing the utility room one doing
the
kitchen. One doing upstairs heating with a programmer/stat, one
doing the
down with another programmer/stat. Upstairs can be off when down is
on
saving on bills. Divide and rule, one shower will not affect the
other
provided the water supply is fine. If one is down you always have
hot water
and heating in the house.

Very cost effective, simple, effective and certainly worth
considering.

Interesting idea, but I guess two small boilers would cost more than
one large. And the installation and servicing would be more costly.

M.

At more than £1700 for the boiler alone (150l) I think that's a bit
too expensive for me. Again I am uncertain of the ventilation
requirements for this boiler.

I put a WB Greenstar 28HE System up in my loft, along with a 180L DPS
Pandora. The price of both boxes was about £1500 total, which might still be
too high for you, but would easily handle two bathrooms. You could always
put in a cheaper boiler to reduce the cost a bit, and can probably get a
better price from DPS than I managed.

I also wonder about the boiler controls. I don't want to have to go
in the loft every time I need to change the boiler settings. Do any
boilers have full remote controls?

What do you mean by controls? I have my main programmer in the understairs
cupboard, although it is always set to 24H on. I then have an S-Plan Plus
setup with programmable thermostats in the master bedroom, lounge, kitchen
and (when they get installed) conservatory and loft conversion. The only
controls left on the boiler itself are the flow temp, which is set and
forget.

Christian.

"Christian McArdle" wrote in message
. net...

The Vaillant AquaPlus is interesting. It
claims to supply 170l in 10 minutes with
a 15 litre storage vessel. I've no idea
how it can achieve this.

It is 37kW, which gives 15.1 litres/min @ 35C delta T. The 15 litres is
stored at aprox 80C (a small thermal store I believe), so giving approx 20
litres at about 40-45C. 15.1 * 10 = 151 + 20 = 171. Near enough 170 litres
in 10 mins. So it will fill a normal bath in about 5 mins.

It is a two stage flowrate combi, giving aprox 17 litres/min dropping to
15.1 litres/min

The AquaPlus has been available on the Continent for a few years, but new
here. I believe it had to be amended to the UK market. Not cheap either.

Can anyone recommend a boiler that is suitable for fitting in a loft
space? We (will) have 4 bedrooms and two bathrooms (both with baths
and showers) so the boiler must handle that.

Almost any modern boiler that you can squeeze through the loft hatch will be
fine. The loft is a particularly good place for a modern condensing boiler
as the plume is clearly not a nuisance going through the roof. Also, modern
boilers tend to be lighter than their older cast iron counterparts.

Whether you go for combi or lots of different storage based solutions
depends on your intended usage profile. However, with 2 proper bathrooms, a
non-storage instantaneous combi would probably not be suitable. You should
be looking for either a large storage based "combi" (which could be
difficult to get into a loft), or a two box solution. In either case, you'll
need to check external dimensions against your loft hatch before ordering.

Using a heat bank or unvented cylinder (rather than a gravity fed cylinder)
would be advantageous, as you don't have to have a high up cold water
cistern, or combination cylinder that may be prone to running out if two
baths or showers are run simultaneously. It also allows a shower in the loft
should you later convert.

Provided your mains water supply has a good flow rate, these solutions will
provide excellent shower and bath performance. If fitting yourself, a heat
bank will be simpler to fit. If fitting professionally, an unvented cylinder
is more likely to be understood by the fitter. The advantages and
disadvantages of each has been done to death in the past, as a quick google
will show.

There are requirements for there to be a proper boarded floor, a fixed (but
retractable if desired) loft ladder, guarding, electric light etc. These are
all useful to have anyway, but must be budgeted for if not already present.

Christian.

"Christian McArdle" wrote in message . net...

[Posted using different news server]

Can anyone recommend a boiler that is suitable for fitting in a loft
space? We (will) have 4 bedrooms and two bathrooms (both with baths
and showers) so the boiler must handle that.

Almost any modern boiler that you can squeeze through the loft hatch will be
fine. The loft is a particularly good place for a modern condensing boiler
as the plume is clearly not a nuisance going through the roof. Also, modern
boilers tend to be lighter than their older cast iron counterparts.

Whether you go for combi or lots of different storage based solutions
depends on your intended usage profile. However, with 2 proper bathrooms, a
non-storage instantaneous combi would probably not be suitable. You should
be looking for either a large storage based "combi" (which could be
difficult to get into a loft), or a two box solution. In either case, you'll
need to check external dimensions against your loft hatch before ordering.

OK. It looks like a non-storage combi will probably not be suitable.
I measured the flow rate of the existing hot water and it's 16.5
litres per minute. The only combi I can find that comes close to this
is the W-B
Greenstar 40 HE Plus which claims a 16L/min flow rate (but I guess the
water
would be colder than ours). The Vaillant AquaPlus is interesting. It
claims
to supply 170l in 10 minutes with a 15 litre storage vessel. I've no
idea
how it can achieve this.

Using a heat bank or unvented cylinder (rather than a gravity fed cylinder)
would be advantageous, as you don't have to have a high up cold water
cistern, or combination cylinder that may be prone to running out if two
baths or showers are run simultaneously. It also allows a shower in the loft
should you later convert.

We won't do a loft conversion because the roof hight makes it too low.
I don't have the skills to fit heating systems myself, so am reliant
on a
plumber. All the plumbers I have contacted only want to fit combi
boilers though.

Provided your mains water supply has a good flow rate, these solutions will
provide excellent shower and bath performance. If fitting yourself, a heat
bank will be simpler to fit. If fitting professionally, an unvented cylinder
is more likely to be understood by the fitter. The advantages and
disadvantages of each has been done to death in the past, as a quick google
will show.

I'm not sure how I can measure the flow rate of the mains. There's
only
two taps connected directly to the supply and their both small.

Is there a FAQ for the pros and cons of unvented cylinders?

There are requirements for there to be a proper boarded floor, a fixed (but
retractable if desired) loft ladder, guarding, electric light etc. These are
all useful to have anyway, but must be budgeted for if not already present.

Should be OK. I was going to do this anyway.

M.

OK. It looks like a non-storage combi will probably not be suitable.
I measured the flow rate of the existing hot water and it's 16.5
litres per minute. The only combi I can find that comes close to this
is the W-B Greenstar 40 HE Plus which claims a 16L/min flow rate (but I
guess the
water would be colder than ours).

Yes, the combi flow rate will be at delta 35 or so. Your old hot water
system is probably on delta 55, so is equivalent to a combi flow rate of 26
litres per minute during winter. During summer, the difference would be less
stark, as the storage system will work as before, whilst the combi will
perform better.

All the plumbers I have contacted only want to fit combi boilers though.

Even combi fanatic could install a DPS Pandora. Explain that all it requires
is cold mains in, hot mains out and standard S-Plan controls to the boiler.
It is much simpler to fit than an old gravity based hot water system.

I'm not sure how I can measure the flow rate of the mains. There's
only two taps connected directly to the supply and their both small.

Measure from these anyway. If even the small taps can provide enough, then
you're laughing. Less than 20 lpm, get worried. 20-30 lpm, OK. 30+, good.
40+, excellent. If you have a garden tap, try that, too.

Is there a FAQ for the pros and cons of unvented cylinders?

There must be somewhere, however, from the top of my head:

Heatbank:
1. Much more simple to install.
2. Fundametally safer due to no storage of pressurised hot water.
3. Lower ongoing maintenance (no safety controls or bubbles to check
annually)
4. Doesn't require certification to be installed professionally.
5. Produces drinking water (assuming no water treatment required).
6. Integral TMV ensures constant DHW temp (some unvented will have this,
too)
7. Potentially faster recovery.
8. Can be fitted without an overflow (useful when no external wall)

Unvented cylinder:
1. More commonly available.
2. Higher potential flow rate.

Don't get bogged down by the differences, though. They are both excellent
solutions.

Christian.

"Christian McArdle" wrote in message . net...
OK. It looks like a non-storage combi will probably not be suitable.
I measured the flow rate of the existing hot water and it's 16.5
litres per minute. The only combi I can find that comes close to this
is the W-B Greenstar 40 HE Plus which claims a 16L/min flow rate (but I
guess the
water would be colder than ours).

Yes, the combi flow rate will be at delta 35 or so. Your old hot water
system is probably on delta 55, so is equivalent to a combi flow rate of 26
litres per minute during winter. During summer, the difference would be less
stark, as the storage system will work as before, whilst the combi will
perform better.

All the plumbers I have contacted only want to fit combi boilers though.

One suggested a vented tank in the roof or a storage combi in the garage.
However the garage may not be built until April next and I know the building
regs are changing and the boiler we would fit would not be condensing.

BTW: Why are vented tanks so unpopular now?

Even combi fanatic could install a DPS Pandora. Explain that all it requires
is cold mains in, hot mains out and standard S-Plan controls to the boiler.
It is much simpler to fit than an old gravity based hot water system.

I'm not sure how I can measure the flow rate of the mains. There's
only two taps connected directly to the supply and their both small.

Measure from these anyway. If even the small taps can provide enough, then
you're laughing. Less than 20 lpm, get worried. 20-30 lpm, OK. 30+, good.
40+, excellent. If you have a garden tap, try that, too.

No garden tap but I'll try to measure the flow rate from the two cold taps
tonight. Incidently another plumber came around yesterday and said that
our flow rate in unlikely to suit an unvented cylinder because we have a
1/2" main (he didn't look at it though, but he does know the area).
I'm not doubting his word, but it has left me even more confused.

Is there a FAQ for the pros and cons of unvented cylinders?

There must be somewhere, however, from the top of my head:

Heatbank:
1. Much more simple to install.
2. Fundametally safer due to no storage of pressurised hot water.
3. Lower ongoing maintenance (no safety controls or bubbles to check
annually)
4. Doesn't require certification to be installed professionally.
5. Produces drinking water (assuming no water treatment required).
6. Integral TMV ensures constant DHW temp (some unvented will have this,
too)
7. Potentially faster recovery.
8. Can be fitted without an overflow (useful when no external wall)

Would a heat bank be inefficient if we only use hot water sporadically?
i.e. very little is used during the day in the week, but loads in the
evening? (I would have thought it would take a lot of energy to keep the
heat bank up to temperature).

Unvented cylinder:
1. More commonly available.
2. Higher potential flow rate.

Why would an unvented cylinder give a higher flow rate? Aren't they
both limited by the mains water flow?

M

BTW: Why are vented tanks so unpopular now?

The poor pressure is unsuited to modern hot water usage (showers) where
pressure is more important than flow rate. Combi boilers, unvented cylinders
and heat banks all use mains pressure, which is ideal.

No garden tap but I'll try to measure the flow rate from the two cold taps
tonight. Incidently another plumber came around yesterday and said that
our flow rate in unlikely to suit an unvented cylinder because we have a
1/2" main (he didn't look at it though, but he does know the area).
I'm not doubting his word, but it has left me even more confused.

In itself, it might not be a problem. The 1/2" section may be short. The
static pressure may be very high, squeezing more water through a smaller
pipe. Only a test will determine the suitability. Note that the storage
mains solutions will still work on a low flow rate, you just don't get the
full advantage until you rip out the old supply and put in some new 25mm
MDPE.

Would a heat bank be inefficient if we only use hot water sporadically?
i.e. very little is used during the day in the week, but loads in the
evening? (I would have thought it would take a lot of energy to keep the
heat bank up to temperature).

Not significantly different from other storage solutions of the same energy
capacity.

Why would an unvented cylinder give a higher flow rate? Aren't they
both limited by the mains water flow?

If they are mains flow rate limited then the heat bank may even have an
advantage, as you don't have a PRV to squeeze through and the route is more
direct. However, the heat bank will have a maximum transfer rate above which
temperatures drop as the plate heat exchanger can't keep up. That rate
varies by manufacturer, but mine is around 40 lpm.

The unvented cylinder does not have this effect. Obviously, 40 lpm @ 60C is
enough for most people, and the heat bank can be specified with a larger
heat exchanger, which could be useful in a commercial setting, such as
sports changing rooms or a hotel, where 40lpm isn't enough during the rush
for showers.

Christian.

"Slartibartfast" wrote in message
om...
"Christian McArdle" wrote in message
. net...

All the plumbers I have contacted only want to fit combi boilers
though.

One suggested a vented tank in the roof
or a storage combi in the garage.
However the garage may not be built
until April next and I know the building
regs are changing and the boiler we would
fit would not be condensing.

BTW: Why are vented tanks so unpopular now?

Crawlies climb in, they take up space, more pipework, more work to install
them, you need a power shower pump to get a decent shower, unless the tank
is way above you.

Measure from these anyway. If even the
small taps can provide enough, then
you're laughing. Less than 20 lpm, get
worried. 20-30 lpm, OK. 30+, good.
40+, excellent. If you have a garden tap, try that, too.

No garden tap but I'll try to measure the
flow rate from the two cold taps
tonight. Incidently another plumber
came around yesterday and said that
our flow rate in unlikely to suit an unvented
cylinder because we have a
1/2" main (he didn't look at it though, but
he does know the area).
I'm not doubting his word, but it has left
me even more confused.

A 1/2" mains can be good enough. Whatever size fit a full bore valve in
place of the existing stop cock. Stop cocks can seriously restrict flow.
It is a worthwhile investment to fit a 25mm MDPE blue plastic mains back to
the stop cock. Many water boards will "connect" the new pipe to the mains
for free.

Would a heat bank be inefficient if
we only use hot water sporadically?

No. They are very well insulated these days.

i.e. very little is used during the day
in the week, but loads in the
evening? (I would have thought it
would take a lot of energy to keep the
heat bank up to temperature).

Not really. A heat bank prevents boiler cycling. You can have a an
"integrated" heat bank. This runs the CH off the heat bank as well as DHW.
Inefficient boiler cycling is virtually eliminated. A heat bank can be on a
timer, so when you are out the boiler is off. Installing a blending valve
on the boiler flow and return will ensure hot water pretty quickly at the
taps.

Unvented cylinder:
1. More commonly available.
2. Higher potential flow rate.

Why would an unvented cylinder give
a higher flow rate? Aren't they
both limited by the mains water flow?

They are limited by the mains. They allow full flow through the cylinder.
Well not quite, as they have pressure reducers on the line. A heat bank can
operate at far higher pressures.

The only point you need high pressure is the shower, all others require good
flow rather than pressure. One cheap and effective solution is:

- A combi that can do two showers, say 14 litres/min. Have the shower only
through the water section of the combi giving high pressure showers
- A combination cylinder/cold water tank with an integral quick recovery
coil. This is all one insulated unit and can go in the loft with no separate
tank.
- Have a combi giving approx 14 litres/min
- heat the cylinder as per usual, but with a priority system of DHW. and all
other hot outlets from the tank/cylinder.

You only need high pressure at the shower, all the rest need volume not
pressure. The Combination cylinder is about the size of a heat bank or
unvented cylinder. As long as the cold tank section is above the highest
bath and basin it will give results. The shower is via the mains via the
combi, so can go anywhere. A combination cylinder stores water at
atmospheric pressure, so no high pressure unvented cylinder that may blow.

"Christian McArdle" wrote in message . net...
I'm not sure how I can measure the flow rate of the mains. There's
only two taps connected directly to the supply and their both small.

Measure from these anyway. If even the small taps can provide enough, then
you're laughing. Less than 20 lpm, get worried. 20-30 lpm, OK. 30+, good.
40+, excellent. If you have a garden tap, try that, too.

I only get 12-13 litres per minutes at those taps. I have have both taps
on at the same time the flow drops off. :-(

M.

On 15 Jul 2004 12:40:23 -0700,
(Slartibartfast) wrote:

"Christian McArdle" wrote in message . net...
I'm not sure how I can measure the flow rate of the mains. There's
only two taps connected directly to the supply and their both small.

Measure from these anyway. If even the small taps can provide enough, then
you're laughing. Less than 20 lpm, get worried. 20-30 lpm, OK. 30+, good.
40+, excellent. If you have a garden tap, try that, too.

I only get 12-13 litres per minutes at those taps. I have have both taps
on at the same time the flow drops off. :-(

M.


Then forget about any form of mains pressure system unless you are
prepared to run pipes internally and probably have a new service pipe
run in from the road. The results would be disappointing.


..andy

To email, substitute .nospam with .gl

I only get 12-13 litres per minutes at those taps. I have have both taps
on at the same time the flow drops off. :-(

Not good. The only hope is that the behaviour was caused by a partially open
stopcock or similar restriction.

You can still put a mains pressure system in if you genuinely intend to
upgrade your supply at some point, but until then, it would be a downgrade
from a gravity based system. If you did decide to install one, consider
feeding the heatbank from the cold water cistern. This could then be
connected to mains instead when the supply pipe was upgraded. If you have no
intention of upgrading the water supply, then a standard gravity system will
be much cheaper.

Christian.