I wnat to change an outside tap so I can screw a hose onto it.

Someone suggested that I can just unscrew my old one and screw a new one
on.

From what I can gather it must be a compression fit tap and 15mm seems
to be standard so I could buy one of these

http://www.screwfix.com/prods/41948/...owflex-15mm-x-
Outside-Tap-with-Hose-Union

There is also one with a check valvle but not sure what that offers?

http://www.screwfix.com/prods/37241/...owflex-15mm-x-
Outside-Tap-with-Check-Valve

I have read a bit on compression fittings. If I am screwing that onto my
existing pipework will I need new oens of these? the 2 bits on the left

or particlarly the bit in the middle which I understand needs to be
repalce with each new fit?

http://www.homewoodheating.co.uk/ima...on-fitting.jpg

As you can see screwfix only provide the tap but not the other bit you
screw and seal it with.

mo brought next idea :
I wnat to change an outside tap so I can screw a hose onto it.

Someone suggested that I can just unscrew my old one and screw a new one
on.

True.

There is also one with a check valvle but not sure what that offers?

The check valve built-in or inline with the feed pipe to the tap is a
requirement. They are a one way valve to prevent foul water being
syphoned back via what ever hose you fit, or if the hose end happens to
fall in a pond - back into the mains.


I have read a bit on compression fittings. If I am screwing that onto my
existing pipework will I need new oens of these? the 2 bits on the left

Probably not, but I seem to remember there is a fibre washer between
tap and its socket - you may need a replacement for that.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

In an earlier contribution to this discussion, mo wrote:
I wnat to change an outside tap so I can screw a hose onto it.

Someone suggested that I can just unscrew my old one and screw a new
one on.

From what I can gather it must be a compression fit tap and 15mm seems
to be standard so I could buy one of these


No, you *don't* need a compression fit tap - you need one which has a male
1/2" BSP thread which screws into the fitting on the wall.

http://www.screwfix.com/prods/41948/...owflex-15mm-x-
Outside-Tap-with-Hose-Union


That is *not* a compression fit tap. It has the right type of thread for
your purposes.


There is also one with a check valvle but not sure what that offers?

http://www.screwfix.com/prods/37241/...owflex-15mm-x-
Outside-Tap-with-Check-Valve


A check valve stops water flowing the wrong way - and thus prevents dirty
water from getting into your mains supply, as could otherwise happen if
there were a supply failure while you had a hose from the tap dipping into
(say) a pond. It's a good idea (may even be mandatory?) to have a check
valve when using an outside tap.

I have read a bit on compression fittings. If I am screwing that onto
my existing pipework will I need new oens of these? the 2 bits on the
left

or particlarly the bit in the middle which I understand needs to be
repalce with each new fit?

http://www.homewoodheating.co.uk/ima...on-fitting.jpg

As you can see screwfix only provide the tap but not the other bit you
screw and seal it with.

You shouldn't need any of that. You should be able to unscrew your existing
tap from its fitting on the wall (which will probably be similar to
http://www.screwfix.com/prods/44390) and screw the new one in. Turn the
water off at the stoptap first, of course!

You *will* need to seal the threads, using either lots of PTFE tape or some
Boss White and hemp. The latter is messier, but you're more likely to be
able to get the threads to go tight when the tap is upright.
--
Cheers,
Roger
_______
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

"Roger Mills" wrote in
:

In an earlier contribution to this discussion, mo
wrote:
I wnat to change an outside tap so I can screw a hose onto it.

Someone suggested that I can just unscrew my old one and screw a new
one on.

From what I can gather it must be a compression fit tap and 15mm
seems to be standard so I could buy one of these


No, you *don't* need a compression fit tap - you need one which has a
male 1/2" BSP thread which screws into the fitting on the wall.

http://www.screwfix.com/prods/41948/...lowflex-15mm-x
- Outside-Tap-with-Hose-Union


That is *not* a compression fit tap. It has the right type of thread
for your purposes.
Thanks - it is described as compression i nthe description?

So I will just buy that one and screw it on then wrap with PTFE tape

cheers

On Tue, 04 May 2010 14:26:09 -0500, mo wrote:

http://www.screwfix.com/prods/41948/...lowflex-15mm-x
- Outside-Tap-with-Hose-Union


That is *not* a compression fit tap. It has the right type of thread
for your purposes.
Thanks - it is described as compression i nthe description?

So I will just buy that one and screw it on then wrap with PTFE tape

NO - you need the one with the check valve, to be legal (and to avoid
possible contamination of your water supply).

--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

fOn Tue, 04 May 2010 14:26:09 -0500, mo wrote:

"Roger Mills" wrote in
:

In an earlier contribution to this discussion, mo
wrote:
I wnat to change an outside tap so I can screw a hose onto it.

Someone suggested that I can just unscrew my old one and screw a new
one on.

From what I can gather it must be a compression fit tap and 15mm
seems to be standard so I could buy one of these


No, you *don't* need a compression fit tap - you need one which has a
male 1/2" BSP thread which screws into the fitting on the wall.

http://www.screwfix.com/prods/41948/...lowflex-15mm-x
- Outside-Tap-with-Hose-Union


That is *not* a compression fit tap. It has the right type of thread
for your purposes.
Thanks - it is described as compression i nthe description?

In this case the 'compression' probably means that it has a
conventional washer which compresses when you turn the tap off, rather
than a 1/4 turn type.

--
Frank Erskine

In an earlier contribution to this discussion, mo wrote:
"Roger Mills" wrote in
:


That is *not* a compression fit tap. It has the right type of thread
for your purposes.

Thanks - it is described as compression i nthe description?


Is it? Where? I didn't see any reference to compression fittings.

So I will just buy that one and screw it on then wrap with PTFE tape


Not quite! You wrap the tape round the threads of the tap *before* you screw
it in, so that the tape ends up *inside* the wall fitting between the male
and female threads, thus effecting a seal. Wrap it clockwise, when looking
from the open end of the male thread towards the tap body, otherwise it will
get forced out when you screw the tap in.

IMHO, Boss White and hemp is preferable in this particular situation. If you
use PTFE tape, unless you're lucky (or skilled, which sounds doubtful!)
you'll end up with a situation where the tap is rotated to a funny angle -
and not upright - when the threads are tight.
--
Cheers,
Roger
_______
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

It happens that Roger Mills formulated :
IMHO, Boss White and hemp is preferable in this particular situation. If you
use PTFE tape, unless you're lucky (or skilled, which sounds doubtful!)
you'll end up with a situation where the tap is rotated to a funny angle -
and not upright - when the threads are tight.

Wrap a fairly even layer of the tape around the entire length of the
threads of the male thread - the tap. The tape is very thin and very
delicate, if you have not come across it before. Just wrap it tight
enough that you can clearly see the shape of the thread, try 2 or 3
layers and add more if it doesn't tighten. One roll should allow you
plenty of practise.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

"Roger Mills" wrote in
:

In an earlier contribution to this discussion, mo
wrote:
"Roger Mills" wrote in
:


That is *not* a compression fit tap. It has the right type of thread
for your purposes.

Thanks - it is described as compression i nthe description?



IMHO, Boss White and hemp is preferable in this particular situation.
If you use PTFE tape, unless you're lucky (or skilled, which sounds
doubtful!) you'll end up with a situation where the tap is rotated to
a funny angle - and not upright - when the threads are tight.

Hemp and Boss White have long since been completly illegal on anything
connected with potable water.

Use only PTFE tape or Loctite String. Whith Loctite you can always turn
back a half turn or so to get the fitting (tap) in the required
position.



--- news://freenews.netfront.net/ - complaints: ---

In an earlier contribution to this discussion, Heliotrope Smith
wrote:

Hemp and Boss White have long since been completly illegal on anything
connected with potable water.


Says who?

If not boss White, you can get Hawk White suitable for potable water, such
as
http://www.screwfix.com/prods/21548/...ater-Hawk-400g

Anyway, I don't suppose that the OP is going to *drink* water from his
outside tap!
--
Cheers,
Roger
_______
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On Tue, 04 May 2010 13:47:11 -0500, mo wrote:

I wnat to change an outside tap so I can screw a hose onto it.

Someone suggested that I can just unscrew my old one and screw a new one
on.

Same type? If so yes.


From what I can gather it must be a compression fit tap and 15mm seems
to be standard so I could buy one of these

http://www.screwfix.com/prods/41948/...owflex-15mm-x-
Outside-Tap-with-Hose-Union


Hereabouts a tap with a "male iron" connection is used in conjunction
with a "male iron" backplate screwed to the wall.

http://www.diynot.com/forums/viewtop...c2 ce0581731f

http://snipurl.com/maleiron [www_diynot_com]

There is also one with a check valvle but not sure what that offers?

It can be a requirement of the water board so as to prevent
contaminated water (from watering cans, hosepipes, whatever) being
drawn back into the supply pipework.


http://www.screwfix.com/prods/37241/...owflex-15mm-x-
Outside-Tap-with-Check-Valve

I have read a bit on compression fittings. If I am screwing that onto my
existing pipework will I need new oens of these? the 2 bits on the left


As a rule only the copper / brass "olive" needs to be changed. These
are very cheap and are generally bought by the bagfull / bubblepack.

or particlarly the bit in the middle which I understand needs to be
repalce with each new fit?


Be aware that a compression fitting with the backnut and olive
removed looks superficially the same as a male iron fitting, but by
golly it's not the same.

http://www.homewoodheating.co.uk/ima...on-fitting.jpg

As you can see screwfix only provide the tap but not the other bit you
screw and seal it with.

Best advice is to replace like with like and replace any olives that
get disturbed.

Derek

"So I will just buy that one and screw it on then wrap with PTFE tape"


No!

PTFE is used to seal threads where the thread is intended to form a seal. It
isn't needed in a compression fitting where the olive uses metal to metal
contact to form a seal. The thread is to pull the parts together.

In an earlier contribution to this discussion, John
wrote:
"So I will just buy that one and screw it on then wrap with PTFE tape"


No!

PTFE is used to seal threads where the thread is intended to form a
seal. It isn't needed in a compression fitting where the olive uses
metal to metal contact to form a seal. The thread is to pull the
parts together.

Yes, but this tap doesn't use any olives - it seals on the 1/2" BSP thread.

Any reference by the OP to "compression fittings" is totally erroneous.
--
Cheers,
Roger
_______
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

mo wrote:
I wnat to change an outside tap so I can screw a hose onto it.

Someone suggested that I can just unscrew my old one and screw a new
one on.

From what I can gather it must be a compression fit tap and 15mm seems
to be standard so I could buy one of these

http://www.screwfix.com/prods/41948/...owflex-15mm-x-
Outside-Tap-with-Hose-Union

There is also one with a check valvle but not sure what that offers?

http://www.screwfix.com/prods/37241/...owflex-15mm-x-
Outside-Tap-with-Check-Valve

I have read a bit on compression fittings. If I am screwing that onto
my existing pipework will I need new oens of these? the 2 bits on the
left

or particlarly the bit in the middle which I understand needs to be
repalce with each new fit?

http://www.homewoodheating.co.uk/ima...on-fitting.jpg

As you can see screwfix only provide the tap but not the other bit you
screw and seal it with.

You can use either tap, the latter has a non return valve to stop back
syphoning - water board paranoia. It does comply with the regs though.

For either you need
http://www.screwfix.com/prods/92934/...e-Elbow-15mm-x


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

"The Medway Handyman" wrote in
:

mo wrote:
I wnat to change an outside tap so I can screw a hose onto it.

Someone suggested that I can just unscrew my old one and screw a new
one on.

From what I can gather it must be a compression fit tap and 15mm
seems to be standard so I could buy one of these

http://www.screwfix.com/prods/41948/...Flowflex-15mm-
x
- Outside-Tap-with-Hose-Union

There is also one with a check valvle but not sure what that offers?

http://www.screwfix.com/prods/37241/...Flowflex-15mm-
x
- Outside-Tap-with-Check-Valve

I have read a bit on compression fittings. If I am screwing that onto
my existing pipework will I need new oens of these? the 2 bits on the
left

or particlarly the bit in the middle which I understand needs to be
repalce with each new fit?

http://www.homewoodheating.co.uk/ima...on-fitting.jpg

As you can see screwfix only provide the tap but not the other bit
you screw and seal it with.

You can use either tap, the latter has a non return valve to stop back
syphoning - water board paranoia. It does comply with the regs
though.

For either you need
http://www.screwfix.com/prods/92934/...g/Compression-
Fittings/Flowf
lex-Wallplate-Elbow-15mm-x



what will i do with that?

------

there seems to be some confusion on here about whether or not that tap
is a compression tap and whether i use PTFE tape

mo wrote:
"The Medway Handyman" wrote in
:

mo wrote:
I wnat to change an outside tap so I can screw a hose onto it.

Someone suggested that I can just unscrew my old one and screw a new
one on.

From what I can gather it must be a compression fit tap and 15mm
seems to be standard so I could buy one of these

http://www.screwfix.com/prods/41948/...Flowflex-15mm-
x - Outside-Tap-with-Hose-Union

There is also one with a check valvle but not sure what that offers?

http://www.screwfix.com/prods/37241/...Flowflex-15mm-
x - Outside-Tap-with-Check-Valve

I have read a bit on compression fittings. If I am screwing that
onto my existing pipework will I need new oens of these? the 2 bits
on the left

or particlarly the bit in the middle which I understand needs to be
repalce with each new fit?

http://www.homewoodheating.co.uk/ima...on-fitting.jpg

As you can see screwfix only provide the tap but not the other bit
you screw and seal it with.

You can use either tap, the latter has a non return valve to stop
back syphoning - water board paranoia. It does comply with the regs
though.

For either you need
http://www.screwfix.com/prods/92934/...g/Compression-
Fittings/Flowf lex-Wallplate-Elbow-15mm-x



what will i do with that?

------

there seems to be some confusion on here about whether or not that tap
is a compression tap and whether i use PTFE tape

OK. Back to basics. There is no such thing as a compression tap AFAIK.

The tap screws into the female thread on the wallplate elbow, the wallplate
elbow is fixed to the wall using the holes on the triangular plate with
screws & plugs. Outside taps don't fit directly onto copper pipes.

The copper pipe supplying the water connects via the compression fitting on
the pipe.

http://i99.photobucket.com/albums/l2...s/tappicky.jpg
HTH


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

In an earlier contribution to this discussion, The Medway Handyman
wrote:

For either you need
http://www.screwfix.com/prods/92934/...e-Elbow-15mm-x


Why? That - or some female threaded equivalent - will already be there with
the existing tap screwed into it. He shouldn't need to replace that.
--
Cheers,
Roger
_______
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

mo wrote:

There is also one with a check valvle but not sure what that offers?

http://www.screwfix.com/prods/37241/...owflex-15mm-x-
Outside-Tap-with-Check-Valve


Just to be clear on the check-valve issue:

1. It is a legal requirement to have a backflow prevention facility on
an outside tap.

See: Statutory Instrument 1999 No. 1148

The Water Supply (Water Fittings) Regulations 1999

Schedule 2 Sec. 2 applies.

http://www.opsi.gov.uk/si/si1999/19991148.htm


2. The WRAC (as was and through this document):

http://www.defra.gov.uk/environment/...9-guidance.pdf

also at: http://preview.tinyurl.com/2exy2tw

deemed (See G15.20 on page 40) that for new installations a double
check-valve located inside a building and protected from freezing
provides suitable protection to incoming mains to prevent backflow from
garden installations (including hosepipes).

For existing installations, G15.21 applies:

G15.21 Where, in existing house installations, a hose pipe is to be
used from an existing hose union tap located outside a house and which
is not provided with backflow protection, either:

a. the existing hose union tap should be provided with a double check
valve located inside the building; or,

http://www.screwfix.com/prods/96336

b. the tap should be replaced with a hose union tap that incorporates a
double check valve (Type HUK1); or,

http://www.screwfix.com/prods/11558

c. a hose union backflow preventer (Type HA) or a double check valve
should be continuously fitted to the outlet of the tap.

http://www.hozelock.com/watering/hos...urn-valve.html

also: http://preview.tinyurl.com/38eep88


Option (a) is the best option, as you don't have a problem with freezing
the valve and wrecking it.

HTH

Thanks all

I bought the screwfix tap with the valve.

Simply unscrewed the old tap.

PTFE tape on the thread of the new one and it screwed onto place - works
fine.


I didn't need the wallplate as the old one sufficed.

Did get confused as I bought a plastic hose pipe thread connector and was
confused as to why it didn;t fit on. But the tap comes with 1 half of the
plastic fitting so I had to throw away half of the plastic fitting!

i.e the tap already came with the black bit he

http://toolspot-static.co.uk/i/763t.jpg