Hi,

Explanations first, then questions at the bottom.

I have read the FAQ from Ed (thanks) but it still hasn't really answered
all my questions.

I have a fairly large 1950s 3 bedroom semi - the lounge is roughly 21 feet
by 11 foot 6, with another 9 feet of extension on the end.

The current boiler is an ageing Baxi back boiler in the middle of
the lounge - fitted to a flue which originally has an open fire.
This does central heating plus a hot water cylinder in a cupboard in the
hall.

Although the system still functions, and I am told I could get a
replacement for the hideous fire at the front of the boiler, I would
really like to replace the system completely.

If possible I would like to reclaim the downstairs cupboard for storage,
(or shelve as a proper airing cupboard with a rad at the bottom).
I wouldn't mind losing the tanks in the loft and associated pipework
either.

I currently have an electric shower, but am used to a power shower; I
would like more flow rate than an electric shower if possible.
Currently planning on only one bathroom, and showers are the norm; we very
rarely fill the bath.

Minimum stay here one year plus; possibility of renting afterwards but may
sell.

I have done a rough flow rate calculation using the cold tap at the bath -
I calibrated an orange B&Q builders bucket at 10 litres up to the spout,
then counted 'one and two' etc. as I didn't have two extra hands to work
the stop watch. It takes about 10 seconds to fill a 10 litre bucket
including the turn on time so flow should be at least 60 litres per minute.

I am working full time at the moment so DIY is not an option.

I am now torn between expense and functionality.

The options as I see it:

(1) Replace gas fire and old cylinder; fit shower pump; larger tank in
loft. Move/replace most of the radiators. I will have to fit TRVs, the
radiators are nasty looking and old, possibly slightly undersized. It is
likely to cost more in time/effort to clean and repaint them to an
acceptable standard than to just replace them.

(2) Large Combi - minimum components but limited throughput of hot water.
Since there will be only one shower, and rare filling of bath, this could
well do as long as it can also heat the radiators. (I am not fond of
Combis after a bad experience in a holiday bungalow where I couldn't get
it to supply hot water to fill the bath).

(3) Pressurised system - I lose the loft tanks but still need someplace
for the hot water cylinder.

(4) Heat store - much the same as (2) if I understand correctly.

As an added complication; I have a downstairs toilet at the back of the
main garage, and I keep thinking that this could be extended to make a
downstairs shower room if I can only work out the logistics. The biggest
problem is having to walk through the back of the garage to get to it. The
second problem is that doing it will probably not add much value to the
house. Still, I would like enough spare capacity to work a second shower
if required.


Yet another complication - where to put the boiler. There is plenty of
room in the loft, and this would suit a Combi, but if I have a pressurised
system or a heat store then either the storage also goes in the loft
(where it will need pretty good insulation) or I have a long run from the
boiler to hot water tank (though this may not be a major problem).

Final issue for the moment - I have one small run of pipe under a floor
(under the doorway to the front room). The concrete covering is crumbling.
I would like to get rid of any underfloor piping if possible. Are there
any problems in running a feed down from upstairs (the radiator will be
under the front bedroom radiator).

QUESTIONS

Which of (2) (3) (4) seems the most cost effective solution?

If I go for (3) or (4) can I have everything including the cylinder/heat
store in the loft?

I have had an outline quote of £4,700 to replace everything with another
non-pressurised system; does this seem reasonable? I guess this is (1a) as
I see I haven't included this in my option list :-)


FURTHER RAMBLINGS

The information I have read in the FAQ has been very useful; however it
doesn't include stuff like the crossover point in cost between the largest
combi and the smallest heat store solutions. The area is further
greyed/water muddied by mixed solutions such as combis with small
additional heat stores.

Real world experience of people who have done a similar job recently would
be most welcome.

Cheers

Dave R

"David WE Roberts" wrote

snip

The area is further
greyed/water muddied by mixed solutions such as combis with small
additional heat stores.

Real world experience of people who have done a similar job recently would
be most welcome.


Just had a Alpha CD50 fitted which comes into your grey area above.
It is fitted in the loft on the gable end wall and is superb. I get power
shower performance from a mira excel thermostatic mixer shower and never
ending hot water.
We only have occasional baths so the normal combi issue does not apply

Regards Jeff

On Sat, 18 Feb 2006 14:27:51 +0000, David WE Roberts wrote:

Hi,

Explanations first, then questions at the bottom.

I have read the FAQ from Ed (thanks) but it still hasn't really answered
all my questions.

I have a fairly large 1950s 3 bedroom semi - the lounge is roughly 21 feet
by 11 foot 6, with another 9 feet of extension on the end.

The current boiler is an ageing Baxi back boiler in the middle of
the lounge - fitted to a flue which originally has an open fire.
This does central heating plus a hot water cylinder in a cupboard in the
hall.

Although the system still functions, and I am told I could get a
replacement for the hideous fire at the front of the boiler, I would
really like to replace the system completely.

If possible I would like to reclaim the downstairs cupboard for storage,
(or shelve as a proper airing cupboard with a rad at the bottom).
I wouldn't mind losing the tanks in the loft and associated pipework
either.

I currently have an electric shower, but am used to a power shower; I
would like more flow rate than an electric shower if possible.
Currently planning on only one bathroom, and showers are the norm; we very
rarely fill the bath.

Minimum stay here one year plus; possibility of renting afterwards but may
sell.

I have done a rough flow rate calculation using the cold tap at the bath -
I calibrated an orange B&Q builders bucket at 10 litres up to the spout,
then counted 'one and two' etc. as I didn't have two extra hands to work
the stop watch. It takes about 10 seconds to fill a 10 litre bucket
including the turn on time so flow should be at least 60 litres per minute.

I am working full time at the moment so DIY is not an option.

I am now torn between expense and functionality.

The options as I see it:

(1) Replace gas fire and old cylinder; fit shower pump; larger tank in
loft. Move/replace most of the radiators. I will have to fit TRVs, the
radiators are nasty looking and old, possibly slightly undersized. It is
likely to cost more in time/effort to clean and repaint them to an
acceptable standard than to just replace them.

(2) Large Combi - minimum components but limited throughput of hot water.
Since there will be only one shower, and rare filling of bath, this could
well do as long as it can also heat the radiators. (I am not fond of
Combis after a bad experience in a holiday bungalow where I couldn't get
it to supply hot water to fill the bath).

(3) Pressurised system - I lose the loft tanks but still need someplace
for the hot water cylinder.

(4) Heat store - much the same as (2) if I understand correctly.

As an added complication; I have a downstairs toilet at the back of the
main garage, and I keep thinking that this could be extended to make a
downstairs shower room if I can only work out the logistics. The biggest
problem is having to walk through the back of the garage to get to it. The
second problem is that doing it will probably not add much value to the
house. Still, I would like enough spare capacity to work a second shower
if required.


Yet another complication - where to put the boiler. There is plenty of
room in the loft, and this would suit a Combi, but if I have a pressurised
system or a heat store then either the storage also goes in the loft
(where it will need pretty good insulation) or I have a long run from the
boiler to hot water tank (though this may not be a major problem).

Final issue for the moment - I have one small run of pipe under a floor
(under the doorway to the front room). The concrete covering is crumbling.
I would like to get rid of any underfloor piping if possible. Are there
any problems in running a feed down from upstairs (the radiator will be
under the front bedroom radiator).

QUESTIONS

Which of (2) (3) (4) seems the most cost effective solution?

If I go for (3) or (4) can I have everything including the cylinder/heat
store in the loft?

I have had an outline quote of £4,700 to replace everything with another
non-pressurised system; does this seem reasonable? I guess this is (1a) as
I see I haven't included this in my option list :-)


FURTHER RAMBLINGS

The information I have read in the FAQ has been very useful; however it
doesn't include stuff like the crossover point in cost between the largest
combi and the smallest heat store solutions. The area is further
greyed/water muddied by mixed solutions such as combis with small
additional heat stores.

Real world experience of people who have done a similar job recently would
be most welcome.

I'm glad the FAQ has been useful for you.

Even the most modest combi will provide more than twice the flow rate of
your electric shower.

Since you have a back boiler (which I assume was adequate albeit
inefficient) we can be pretty certain the heating load will be satisfied
with 18kW or less.

Without a good look at your house no one can say just where the new boiler
should go. The loft is perhaps the least favourite choice as there are a
number of restrictions if doing the job proerpy which make everywhere else
less hassle.

A properly installed 28kW plain combi sounds like it might be OK for your
needs.

There is not much in cost-wise to choose between a thermal store and an
unvented cylinder (of an appropriate size), since your not diying this
aspect you can go either way.

Stored hot water is likely to add around £1000-£1500 versus the plain
combi option.

A new vented cylinder would probably add around £500. The cylinder being
cheaper to purchase, but the location would best be below the loft.
however once you have adding in a decent shower pump the cost
differentials start to close up between all the forms of stored HW.

The radiator replacements would add around £50-£150 per rad depending on
the quality of the radiator.

HTH

--

Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

On Sat, 18 Feb 2006 14:27:51 +0000 someone who may be David WE
Roberts wrote this:-

As an added complication; I have a downstairs toilet at the back of the
main garage, and I keep thinking that this could be extended to make a
downstairs shower room if I can only work out the logistics.

Depending on where this is situated in relation to the rest of the
house it may well not be sensible to take hot water from the house.
If this is the case a better solution is local instant heating,
either electric or gas.

The main source of hot water is best situated near the tap that is
used the most, usually the kitchen one. If the other rooms that have
hot water are clustered tightly around this, horizontally or
vertically, then that minimises losses.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

"Ed Sirett" wrote in message
news
Without a good look at your house no
one can say just where the new boiler
should go. The loft is perhaps the least
favourite choice as there are a number
of restrictions if doing the job proerpy
which make everywhere else
less hassle.

The loft is the best place. All you need do is board it out from hatch to
boier, a permanent light and if the boiler is near t the hatch a rail around
the hatch (wood on the rafters will do) and fit the combi high up so it
cannot be used to items on.

A properly installed 28kW plain combi sounds
like it might be OK for your needs.

I would go for the highest flowrate combi he can get. He have two showers on
the go. Alpha CD50, Baxi 133 HE Plus (can use TRVs opn 'all' rads with this
boiler, W-Bosch 40kW, highflow Glow Worms. All wall mounted.

There is not much in cost-wise to choose between
a thermal store and an unvented cylinder (of an
appropriate size), since your not diying this
aspect you can go either way.

Avoid an unvenetd cylinder as it requires an annual service charge. No
service and a flood and the insurance company will not pay up. They can
also explode.
http://www.waterheaterblast.com/
This was half the size odf a normal domestic cylinder. They can take down
the side of a house.

Stored hot water is likely to add
around £1000-£1500 versus the plain
combi option.

Yep.

A new vented cylinder would probably add
around £500.

...and the rest

The cylinder being cheaper to purchase,
but the location would best be below the loft.

A combination cylinder can be fitted in the loft.

however once you have adding in a
decent shower pump the cost
differentials start to close up between
all the forms of stored HW.

Yep. And the noisey, space consuming and prone to leaking pump.

"David Hansen" wrote in message
...

The main source of hot water is best situated near the tap that is
used the most, usually the kitchen one. If the other rooms that have
hot water are clustered tightly around this, horizontally or
vertically, then that minimises losses.

If gaining space is the aim then put the combi or water store. when
convenient and install a DHW secondary circulation loop. Lag 'all' DHW
draw-off pipes.

On Sat, 18 Feb 2006 14:27:51 +0000, David WE Roberts wrote:

snip

Thanks for all the responses so far.

Looking through them, I can see I left out an important part of the
explanation.

There is a problem about siting the boiler.

All the drainage is at the back of the house.
So is the kitchen, bathroom, toilet.
This is where the water main comes up through the floor.

I can't put the boiler at the front of the house as there is not much wall
which is not lounge window or front door.
In the hall it would block the lounge door or the stairs.
In the lounge it would be an eyesore.
I would also have to run the pipes up the wall and through the upstairs
floor to get to the kitchen and bathroom at the back.

I can't put the boiler on the LHS (looking from the front) as it is a semi
and it might make my neighbour's lounge cloudy.

I cant put the boiler on the ground floor RHS as I have an integral garage
which runs the full length of the house, and links to the old garage at
the rear of the house.

I can't (I think) put the boiler in the garage as it runs right up to the
boundary and the vent would therefore be into the neighbour's property.
Perhaps I could vent vertically through the flat roof?
Another possibility is the downstairs toilet, which is at the back of the
garage where it reaches beyond the back of the kitchen and has some
outside wall space. Not a massive amount of floor space, though. Cold and
damp in the winter.

The only obvious place on the ground floor is in the kitchen, where I have
about 1 metre of outside wall to the right of the window.
However I don't have that much room in the kitchen and I was planning to
hang storage cupboards there.

Similar problems upstairs.
No back wall space obvious ( although it could perhaps go in the toilet
above the low level cistern). It would have to be a slim as the cistern,
though.

No side wall space (all stairs, window, and smallest upstairs bedroom to
the front).

My favoured place would be in the loft at the gable end.
Loads of unused space, close to bathroom and toilet, directly above the
kitchen, and I can use the gable end or the roof for a vent.

Closest suggestion so far is Jeff's Alpha CD50.
Any known problem,s with this unit, or good alternatives (Jeff, close your
eyes at this point since you have already bought one and don't really want
to know)?

Cheers

Dave R

"David WE Roberts" wrote in message
news
My favoured place would be in
the loft at the gable end.
Loads of unused space, close to
bathroom and toilet, directly above the
kitchen, and I can use the gable end
or the roof for a vent.

Sounds good. More hassle but if you can get it through the roof, much
neater.

Closest suggestion so far is Jeff's Alpha CD50.
Any known problem,s with this unit, or good
alternatives (Jeff, close your eyes at this point
since you have already bought one and don't really want
to know)?

Excellent choice. 5 year guarantee. and a highflow rate that fills a bath
very quickly. Will do two simultanteous showers. Look at the other boilers
I mentioned. They are all wall mounted units. In the loft they can be on a
Unistrut frame off the rafers, so no need to actually be on the gable end.
There are also high flowrate floor mounted units that give excellent
flowrates. The Potterton Powermax breaks down so it can be lifted into the
loft. Make sure it is well supported on the loft though. The Viessmann 333
is a floor mounted job and of RR class. You get what you pay for.

On Sun, 19 Feb 2006 11:38:07 -0000 someone who may be "Doctor
Drivel" wrote this:-

If gaining space is the aim then put the combi or water store. when
convenient and install a DHW secondary circulation loop.

Provided one is prepared to put up with the standing losses over a
decade or two. When these are pointed out some decide that saving a
bit more space isn't as great a priority as they thought it was.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On Sun, 19 Feb 2006 12:53:28 +0000, David Hansen wrote:

On Sun, 19 Feb 2006 11:38:07 -0000 someone who may be "Doctor
Drivel" wrote this:-

If gaining space is the aim then put the combi or water store. when
convenient and install a DHW secondary circulation loop.

Provided one is prepared to put up with the standing losses over a
decade or two. When these are pointed out some decide that saving a
bit more space isn't as great a priority as they thought it was.

In my particular case, putting the boiler in the loft should place it
closer to the bathroom and as close to the kitchen as the current hot
water cylinder.

I don't think I need a loop - the runs aren't that long.

Cheers

Dave R

"David WE Roberts" wrote in message
news
On Sat, 18 Feb 2006 14:27:51 +0000, David WE Roberts wrote:

snip


My favoured place would be in the loft at the gable end.
Loads of unused space, close to bathroom and toilet, directly above the
kitchen, and I can use the gable end or the roof for a vent.

Closest suggestion so far is Jeff's Alpha CD50.
Any known problem,s with this unit, or good alternatives (Jeff, close your
eyes at this point since you have already bought one and don't really want
to know)?


even with hindsight I dont think I could choose a better boiler.
If you are near the midlands you are welcome to have a look. People talking
flow rates and seeing for yourself are totally different, I would have loved
to have seen before I bought.

Regards Jeff

"David Hansen" wrote in message
...
On Sun, 19 Feb 2006 11:38:07 -0000 someone who may be "Doctor
Drivel" wrote this:-

If gaining space is the aim then put the combi or water store. when
convenient and install a DHW secondary circulation loop.

Provided one is prepared to put up with the standing losses over a
decade or two. When these are pointed out some decide that saving a
bit more space isn't as great a priority as they thought it was.

IFAIAC, 'all' DHW draw-off pipes should be lagged. An insulated secondary
loop will not loose too much heat and with a pipe state the pumps will only
come on when the loop has cooled. With a secondary circulation loop you
waste far less water keeping water bills down. Water flow at each tap can be
throttled back as hot water is instantly available at the tap. People will
accept low flows as long as there is instant water at the taps.

On Sun, 19 Feb 2006 13:08:53 +0000, Owain wrote:

David WE Roberts wrote:
There is a problem about siting the boiler.
snip
No back wall space obvious ( although it could perhaps go in the toilet
above the low level cistern). It would have to be a slim as the cistern,
though.

Bring the WC/cistern forward to increase the depth available?

Owain

Only if I want to sit with my feet sticking out onto the landing :-)

Dave R

On Sat, 18 Feb 2006 14:27:51 +0000, David WE Roberts
wrote:


I have a fairly large 1950s 3 bedroom semi - the lounge is roughly 21 feet
by 11 foot 6, with another 9 feet of extension on the end.

I currently have an electric shower, but am used to a power shower; I
would like more flow rate than an electric shower if possible.
Currently planning on only one bathroom, and showers are the norm; we very
rarely fill the bath.

Minimum stay here one year plus; possibility of renting afterwards but may
sell.

I'd get a cheap Combi fitted. (B&Q were recently selling combis for
£299 upwards.)

The logic behind this is that it'd probably be the cheapest option
overall and will allow you to recoup cuboard space.

The fact it's a new boiler will almost cerrtainly help the sale of the
house rather than detract from it because it's cheap.

You'll only be living with the thing for a few years so quality and
longevity isn't a hugely important factor.

sponix

"sponix" wrote in message
...
On Sat, 18 Feb 2006 14:27:51 +0000, David WE Roberts
wrote:


I have a fairly large 1950s 3 bedroom semi - the lounge is roughly 21 feet
by 11 foot 6, with another 9 feet of extension on the end.

I currently have an electric shower, but am used to a power shower; I
would like more flow rate than an electric shower if possible.
Currently planning on only one bathroom, and showers are the norm; we very
rarely fill the bath.

Minimum stay here one year plus; possibility of renting afterwards but may
sell.

I'd get a cheap Combi fitted. (B&Q were
recently selling combis for
£299 upwards.)

The logic behind this is that it'd probably
be the cheapest option overall and will
allow you to recoup cuboard space.

The logic behind that is that he will have stiil trouble from a cheap and
nasty product as he is renting out. Whether he is there or not it is still
his problem. Best get a quality product that will give some sort of
longevity and reliability.

David WE Roberts wrote:
I have done a rough flow rate calculation using the cold tap at the bath -
I calibrated an orange B&Q builders bucket at 10 litres up to the spout,
then counted 'one and two' etc. as I didn't have two extra hands to work
the stop watch. It takes about 10 seconds to fill a 10 litre bucket
including the turn on time so flow should be at least 60 litres per minute.

Invalid for flow rate. Measure at kitchen cold tap, at 9 am,12.00 and
6pm to get a clearer picture.

Regards
Capitol

On Sun, 19 Feb 2006 13:47:32 +0000, Jeff wrote:


"David WE Roberts" wrote in message
news
On Sat, 18 Feb 2006 14:27:51 +0000, David WE Roberts wrote:

snip


My favoured place would be in the loft at the gable end.
Loads of unused space, close to bathroom and toilet, directly above the
kitchen, and I can use the gable end or the roof for a vent.

Closest suggestion so far is Jeff's Alpha CD50.
Any known problem,s with this unit, or good alternatives (Jeff, close your
eyes at this point since you have already bought one and don't really want
to know)?


even with hindsight I dont think I could choose a better boiler.
If you are near the midlands you are welcome to have a look. People talking
flow rates and seeing for yourself are totally different, I would have loved
to have seen before I bought.


To date Alpha have not been known for their offerings being even half way
up the spectrum. However it is possible that they wish to reposition
themselves in the market.

The lift weight of 70kg is something of a challenge for a loft
installation.

The price from one online store was 1490 including VAT.
However other boilers I know the price of were somewhat up on that site.
So quite possible £1350 (inc) would be the going trade rate.

This certainly puts it in the right segment of the market if Alpha are
genuinely repositioning themselves.



--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

"Ed Sirett" wrote in message
news
even with hindsight I dont think I could
choose a better boiler. If you are near
the midlands you are welcome to have a
look. People talking flow rates and seeing for yourself are totally
different, I would have loved
to have seen before I bought.

To date Alpha have not been known for
their offerings being even half way
up the spectrum.

They were always in the middle.

However it is possible
that they wish to reposition
themselves in the market.

With new designs and 5 year guarantees they obviously intent to. Many have
integral cyclone filters on the return to catch solids. Crud in boiler
exchanges is a major cause of boiler problems

The lift weight of 70kg is something
of a challenge for a loft
installation.

The price from one online store was
1490 including VAT. However other
boilers I know the price of were somewhat
up on that site. So quite possible £1350 (inc)
would be the going trade rate.

Look at:
http://www.uselessenergy.org.uk/boilers_prices.asp
£912.56 inc VAT and delivery

This certainly puts it in the right segment of the market if Alpha are
genuinely repositioning themselves.

On Sun, 19 Feb 2006 21:04:54 -0000, "Doctor Drivel"
wrote:


The logic behind that is that he will have stiil trouble from a cheap and
nasty product as he is renting out. Whether he is there or not it is still
his problem. Best get a quality product that will give some sort of
longevity and reliability.

He said he *may* rent it out or *may* sell.

If he sells then a cheap boiler is the best option.

If he decides to rent then a cheap boiler is still the best option
imo. Firstly, tenants have a habit of breaking things and it's better
that they break a cheap boiler than an expensive one.

Secondly, he can replace the cheap boiler with an expensive one five
or ten years down the road and presumably offset the cost for taxation
purposes.

sponix

On Mon, 20 Feb 2006 00:02:26 +0000, Jeff wrote:


"Capitol" wrote in message
...


David WE Roberts wrote:
I have done a rough flow rate calculation using the cold tap at the
bath -
I calibrated an orange B&Q builders bucket at 10 litres up to the spout,
then counted 'one and two' etc. as I didn't have two extra hands to work
the stop watch. It takes about 10 seconds to fill a 10 litre bucket
including the turn on time so flow should be at least 60 litres per
minute.

Invalid for flow rate. Measure at kitchen cold tap, at 9 am,12.00 and
6pm to get a clearer picture.

Measure at biggest mains fed tap - taps can be restriction

Regards Jeff

Exactly - which is why I used the bath tap :-)

In article ,
David WE Roberts wrote:
I have done a rough flow rate calculation using the cold tap at the bath
- I calibrated an orange B&Q builders bucket at 10 litres up to the
spout, then counted 'one and two' etc. as I didn't have two extra hands
to work the stop watch. It takes about 10 seconds to fill a 10 litre
bucket including the turn on time so flow should be at least 60 litres
per minute.

Sounds like that's coming off the header tank.

--
*The more people I meet, the more I like my dog.

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

"David WE Roberts" wrote in message
news
On Mon, 20 Feb 2006 00:02:26 +0000, Jeff wrote:


"Capitol" wrote in message
...


David WE Roberts wrote:
I have done a rough flow rate calculation using the cold tap at the
bath -
I calibrated an orange B&Q builders bucket at 10 litres up to the
spout,
then counted 'one and two' etc. as I didn't have two extra hands to
work
the stop watch. It takes about 10 seconds to fill a 10 litre bucket
including the turn on time so flow should be at least 60 litres per
minute.

Invalid for flow rate. Measure at kitchen cold tap, at 9 am,12.00 and
6pm to get a clearer picture.

Measure at biggest mains fed tap - taps can be restriction

Regards Jeff

Exactly - which is why I used the bath tap :-)

You said you have a tank/cylinder arrangement. Is that off the cold water
mains? 60 litres/min appears excessive.

On Mon, 20 Feb 2006 12:25:01 +0000, Dave Plowman (News) wrote:

In article ,
David WE Roberts wrote:
I have done a rough flow rate calculation using the cold tap at the bath
- I calibrated an orange B&Q builders bucket at 10 litres up to the
spout, then counted 'one and two' etc. as I didn't have two extra hands
to work the stop watch. It takes about 10 seconds to fill a 10 litre
bucket including the turn on time so flow should be at least 60 litres
per minute.

Sounds like that's coming off the header tank.

Thanks Dave, I'd missed that when I replied earlier.
The OP needs to measure the flow rate of cold at the kitchen sink, he'll
need 20litres/min to fit the Alpha CD50.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

On Mon, 20 Feb 2006 21:06:58 +0000, Ed Sirett wrote:

On Mon, 20 Feb 2006 12:25:01 +0000, Dave Plowman (News) wrote:

In article ,
David WE Roberts wrote:
I have done a rough flow rate calculation using the cold tap at the bath
- I calibrated an orange B&Q builders bucket at 10 litres up to the
spout, then counted 'one and two' etc. as I didn't have two extra hands
to work the stop watch. It takes about 10 seconds to fill a 10 litre
bucket including the turn on time so flow should be at least 60 litres
per minute.

Sounds like that's coming off the header tank.

Thanks Dave, I'd missed that when I replied earlier.
The OP needs to measure the flow rate of cold at the kitchen sink, he'll
need 20litres/min to fit the Alpha CD50.

Hmmm....I'm pretty sure that the cold water is coming from the mains, not
the header tank,but I will check.
If I am getting this pressure from the header tank (around 8' head from
the tank (top of water level) to the bath tap then this is pretty
impressive.
I thought that in general cold should come from the mains (therefore
suitable for drinking), and also there seems no point in taking cold water
from the tank as it reduces the amount available for the hot tap.

You obviously need tank fed for applications such as a power shower where
balanced input pressures are needed.
..
..
..
..
..
{puff, pant}
..
..
Yep - mains pressure.
Checks:
(1) I turned the hot tap on and ran it for about 5 seconds. I could hear
the cistern in the loft start to fill. This ran on for a bit after I
turned the hot tap off.
(2) I turned the cold tap on. About twice the perceived pressure, and no
cistern filling sounds during or after running the cold tap.

I used the bath tap as a test because
(a) I knew there was restricted flow from the kitchen tap
(b) From looking at visible pipes I think that the bath is fed by 3/4"
cold mains as opposed to the 15mm to the kitchen tap, thus giving a better
measure of potential flow.

Still, worthwhile double checking.

Cheers

Dave R

On Mon, 20 Feb 2006 13:30:20 +0000, Doctor Drivel wrote:


"David WE Roberts" wrote in message
news
On Mon, 20 Feb 2006 00:02:26 +0000, Jeff wrote:


"Capitol" wrote in message
...


David WE Roberts wrote:
I have done a rough flow rate calculation using the cold tap at the
bath -
I calibrated an orange B&Q builders bucket at 10 litres up to the
spout,
then counted 'one and two' etc. as I didn't have two extra hands to
work
the stop watch. It takes about 10 seconds to fill a 10 litre bucket
including the turn on time so flow should be at least 60 litres per
minute.

Invalid for flow rate. Measure at kitchen cold tap, at 9 am,12.00 and
6pm to get a clearer picture.

Measure at biggest mains fed tap - taps can be restriction

Regards Jeff

Exactly - which is why I used the bath tap :-)

You said you have a tank/cylinder arrangement. Is that off the cold water
mains? 60 litres/min appears excessive.


I prefer to think of it as impressive :-)

As posted higher up, I have checked and it is from the mains.

In article ,
David WE Roberts wrote:
Sounds like that's coming off the header tank.

Thanks Dave, I'd missed that when I replied earlier. The OP needs to
measure the flow rate of cold at the kitchen sink, he'll need
20litres/min to fit the Alpha CD50.

Hmmm....I'm pretty sure that the cold water is coming from the mains,
not the header tank,but I will check. If I am getting this pressure from
the header tank (around 8' head from the tank (top of water level) to
the bath tap then this is pretty impressive.

No - just means the pipe runs are well done. Remember it's 22mm pipe too.

I thought that in general cold should come from the mains (therefore
suitable for drinking),

You drink bath water? ;-)

and also there seems no point in taking cold
water from the tank as it reduces the amount available for the hot tap.

They're two separate pipe runs, and the header tank holds much more water
than the hot water cylinder.

You obviously need tank fed for applications such as a power shower where
balanced input pressures are needed.

--
*Stable Relationships Are For Horses. *

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

David WE Roberts wrote:

On Mon, 20 Feb 2006 13:30:20 +0000, Doctor Drivel wrote:


"David WE Roberts" wrote in message
news
On Mon, 20 Feb 2006 00:02:26 +0000, Jeff wrote:


"Capitol" wrote in message
...


David WE Roberts wrote:

I have done a rough flow rate calculation using the cold tap at the

bath -

I calibrated an orange B&Q builders bucket at 10 litres up to the
spout,
then counted 'one and two' etc. as I didn't have two extra hands to
work
the stop watch. It takes about 10 seconds to fill a 10 litre bucket
including the turn on time so flow should be at least 60 litres per

minute.

Invalid for flow rate. Measure at kitchen cold tap, at 9 am,12.00 and
6pm to get a clearer picture.


Measure at biggest mains fed tap - taps can be restriction

Regards Jeff

Exactly - which is why I used the bath tap :-)

You said you have a tank/cylinder arrangement. Is that off the cold water
mains? 60 litres/min appears excessive.


I prefer to think of it as impressive :-)

As posted higher up, I have checked and it is from the mains.

Seems ok. I,m surprised at the flow rate. If you stick your thumb over
the end of the bath tap, how easy is it to stop the flow, compared to
the kitchen sink tap? Wear raincoat?

Regards
Capitol

On Thu, 23 Feb 2006 00:01:15 +0000, Capitol wrote:



David WE Roberts wrote:

On Mon, 20 Feb 2006 13:30:20 +0000, Doctor Drivel wrote:


"David WE Roberts" wrote in message
news
On Mon, 20 Feb 2006 00:02:26 +0000, Jeff wrote:


"Capitol" wrote in message
...


David WE Roberts wrote:

I have done a rough flow rate calculation using the cold tap at the

bath -

I calibrated an orange B&Q builders bucket at 10 litres up to the
spout,
then counted 'one and two' etc. as I didn't have two extra hands to
work
the stop watch. It takes about 10 seconds to fill a 10 litre bucket
including the turn on time so flow should be at least 60 litres per

minute.

Invalid for flow rate. Measure at kitchen cold tap, at 9 am,12.00 and
6pm to get a clearer picture.


Measure at biggest mains fed tap - taps can be restriction

Regards Jeff

Exactly - which is why I used the bath tap :-)

You said you have a tank/cylinder arrangement. Is that off the cold water
mains? 60 litres/min appears excessive.


I prefer to think of it as impressive :-)

As posted higher up, I have checked and it is from the mains.

Seems ok. I,m surprised at the flow rate. If you stick your thumb over
the end of the bath tap, how easy is it to stop the flow, compared to
the kitchen sink tap? Wear raincoat?

Thank you for your generous offer of late night entertainment but
unfortunately I will have to decline.

The pressure does seem high - so high I have no intention of putting my
thumb over the end :-)

I will re-check the flow rate as it seems far higher than most expect -
but I may just be close to the source of the water with decent piping
between me and whatever pressurises the water main.

I assume that people living next door to a water tower (or pumping
station) may get awesome pressure/flow rate compared to those at the
remoter parts of the system.

It does look as though a larger power combi may fit my requirements, given
the potential flow rate.

Cheers

Dave R

"David WE Roberts" wrote in message
news
On Mon, 20 Feb 2006 13:30:20 +0000, Doctor Drivel wrote:


"David WE Roberts" wrote in message
news
On Mon, 20 Feb 2006 00:02:26 +0000, Jeff wrote:


"Capitol" wrote in message
...


David WE Roberts wrote:
I have done a rough flow rate calculation using the cold tap at the
bath -
I calibrated an orange B&Q builders bucket at 10 litres up to the
spout,
then counted 'one and two' etc. as I didn't have two extra hands to
work
the stop watch. It takes about 10 seconds to fill a 10 litre bucket
including the turn on time so flow should be at least 60 litres per
minute.

Invalid for flow rate. Measure at kitchen cold tap, at 9 am,12.00 and
6pm to get a clearer picture.

Measure at biggest mains fed tap - taps can be restriction

Regards Jeff

Exactly - which is why I used the bath tap :-)

You said you have a tank/cylinder arrangement. Is that off the cold
water
mains? 60 litres/min appears excessive.

I prefer to think of it as impressive :-)

As posted higher up, I have checked and it is from the mains.

I am impressed. Always have a mains pressure system.

"David WE Roberts" wrote in message
news
It does look as though a larger power
combi may fit my requirements, given
the potential flow rate.

Dave R

Yep. That is the way. Make sure the combi has its own dedicated feed from
the stoptap.

"David WE Roberts" wrote in message
news
You obviously need tank fed for applications
such as a power shower where
balanced input pressures are needed.

If using a pump yes. If using the mains then an integral equalisation valve
in the mixer will do. They can be external.