such choice - is it just personal preference or are some types more suited
than others for certain applications? I have always liked ball valves for
their ease and speed of operation, but I need to add/replace some valves and
wondered if ball is the way to go here (all 15mm copper pipe)

* Cold feed to boiler (& washing machine) and hot water from boiler to rest
of house
* Isolation for outside bib tap
* Sink taps (I assume small "service" valves with a screw rather than a
handle - these are small ball valves too arent they?)


Also, does a 15mm end feed elbow add significant restriction to the flow as
opposed to a 90deg bent pipe (bearing in mind there is ~10 l/min restriction
on the flow anyway in the combi boiler)? I could always reuse the existing
bend after cleaning it up but I have no means of bending new pipe at the
moment.


cheers

Dave.

On Sat, 28 Aug 2004 21:49:41 +0100, "a" wrote:

such choice - is it just personal preference or are some types more suited
than others for certain applications? I have always liked ball valves for
their ease and speed of operation, but I need to add/replace some valves and
wondered if ball is the way to go here (all 15mm copper pipe)

* Cold feed to boiler (& washing machine) and hot water from boiler to rest
of house
* Isolation for outside bib tap

Lever ball valves are a good choice for these.


* Sink taps (I assume small "service" valves with a screw rather than a
handle - these are small ball valves too arent they?)


They are, but are not full bore and do restrict the flow somewhat.
If the taps are on the mains (and as you say, a combi), then this may
not be too important.

Another option is to use lever ball valves and to take the handles off
if they are in the way.



Also, does a 15mm end feed elbow add significant restriction to the flow as
opposed to a 90deg bent pipe (bearing in mind there is ~10 l/min restriction
on the flow anyway in the combi boiler)? I could always reuse the existing
bend after cleaning it up but I have no means of bending new pipe at the
moment.


It's equivalent to approximately 0.5m of pipe, so again not a big deal
if you have one and the supply is from the mains, but have ten and you
would notice it.

You can get swept bends which have less of an impact, but if it's only
one bend, I doubt that you would notice.



cheers

Dave.


..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
On Sat, 28 Aug 2004 21:49:41 +0100, "a" wrote:

such choice - is it just personal preference or are some types more
suited
than others for certain applications? I have always liked ball valves for
their ease and speed of operation, but I need to add/replace some valves
and
wondered if ball is the way to go here (all 15mm copper pipe)

* Cold feed to boiler (& washing machine) and hot water from boiler to
rest
of house
* Isolation for outside bib tap

Lever ball valves are a good choice for these.


* Sink taps (I assume small "service" valves with a screw rather than a
handle - these are small ball valves too arent they?)


They are, but are not full bore and do restrict the flow somewhat.
If the taps are on the mains (and as you say, a combi), then this may
not be too important.

Another option is to use lever ball valves and to take the handles off
if they are in the way.



Also, does a 15mm end feed elbow add significant restriction to the flow
as
opposed to a 90deg bent pipe (bearing in mind there is ~10 l/min
restriction
on the flow anyway in the combi boiler)? I could always reuse the
existing
bend after cleaning it up but I have no means of bending new pipe at the
moment.


It's equivalent to approximately 0.5m of pipe, so again not a big deal
if you have one and the supply is from the mains, but have ten and you
would notice it.

You can get swept bends which have less of an impact, but if it's only
one bend, I doubt that you would notice.

.andy

Thanks Andy, balls and elbows it is then )

"a" wrote in
:

such choice - is it just personal preference or are some types more
suited than others for certain applications? I have always liked ball
valves for their ease and speed of operation, but I need to
add/replace some valves and wondered if ball is the way to go here
(all 15mm copper pipe)

I would always fit full bore ball valves from new, and always replace
stopcocks and gate valves with them when replacemnent is required; and
replace with them right away in flow critical areas.

Recently on advice from here (maybe Andy, I can't recomember) I put a 22mm
full bore lever valve in the feed to my new HW cylinder.

It stayed for weeks with the cold tank full, and no pipe connected, and
didn't lose a drop; no gate valve would do that.

When I'd finished and opened it the flow was scary! It beat the mains
supply to the cold tank by gallons.

mike