My cold water supply to the kitchen is 15mm copper, reasonably straight
with no tees, for the 6m or so that I've seen. The remainder to the
connection with the main, maybe another 5m, I've never seen but have no
reason to suspect it's any different.

There is a stopcock under the sink which isolates the cold tap and a
supply to the combi boiler. This is not fully open, I backed it off to
just before the point at which it affects the flow through the combi.
We have reasonble mains pressure and this stops the cold tap running
like a fire hose.

I have a new Pegler tap fitted with conventional washers. When the cold
is turned on it starts just fine then dwindles away to nothing in about
5s. Further opening of the tap restores the flow.

Any idea what could cause this? Is it likely to be the tap washer
and/or is my tinkering with the stopcock setting ill advised? I even
wondered if it was a design feature of the tap, attempting to give a
consistent flow across variable mains pressure, and failing.

urchaidh wrote in message
oups.com...
My cold water supply to the kitchen is 15mm copper, reasonably straight
with no tees, for the 6m or so that I've seen. The remainder to the
connection with the main, maybe another 5m, I've never seen but have no
reason to suspect it's any different.

There is a stopcock under the sink which isolates the cold tap and a
supply to the combi boiler. This is not fully open, I backed it off to
just before the point at which it affects the flow through the combi.
We have reasonble mains pressure and this stops the cold tap running
like a fire hose.

I have a new Pegler tap fitted with conventional washers. When the cold
is turned on it starts just fine then dwindles away to nothing in about
5s. Further opening of the tap restores the flow.

Any idea what could cause this? Is it likely to be the tap washer
and/or is my tinkering with the stopcock setting ill advised? I even
wondered if it was a design feature of the tap, attempting to give a
consistent flow across variable mains pressure, and failing.


Possibly it's just something inside the tap mechanism contracting and
reducing the flow as the cold water cools the body of the tap down. I have
something similar with a hot tap which slows to a trickle as it gets hot.
--
Dave Baker

Possibly it's just something inside the tap mechanism contracting and
reducing the flow as the cold water cools the body of the tap down. I have
something similar with a hot tap which slows to a trickle as it gets hot.
--
Dave Baker

I've had the same but a Dave says, "Only with a hot tap". Why not
check the actual water temperature with a thermometer. I think that
ought to be a good indicator of ground temperature too, providing you
do not flow too fast.

I don't see why you shouldn't get the same phenomenom witha cold tap.

Chris.

urchaidh wrote:
I have a new Pegler tap fitted with conventional washers. When the cold
is turned on it starts just fine then dwindles away to nothing in about
5s. Further opening of the tap restores the flow.

I've has a similar problem. The washer sits in a cup attached to
the "jumper":

|/|
|/| - internally threaded
___| |___
|#### ####| # = washer
|
X

There *was* a copper screw and washer (X- above) that retained the
tap washer. It broke off, leaving the washer free. The remains of
it were visible in the body of the tap where they.When the tap was
turned on, somehow the washer was able to move and obstruct the
flow. Mine's waiting for me to get a tuit. I don't know whether
I'll be able to get the copper screw stub out, or whether you can
buy a new "jumper".

On 24 Nov 2005 03:28:10 -0800, "urchaidh" wrote:


I have a new Pegler tap fitted with conventional washers. When the cold
is turned on it starts just fine then dwindles away to nothing in about
5s. Further opening of the tap restores the flow.

Any idea what could cause this? Is it likely to be the tap washer
and/or is my tinkering with the stopcock setting ill advised? I even
wondered if it was a design feature of the tap, attempting to give a
consistent flow across variable mains pressure, and failing.

Either the water pressure is too low or more likely it's the o ring
sealing the spindle to the tap upper body which is either displaced or
hanging up due to lack of lubrication. If the flow changes when you
either press down or lift the tap handle then this is usually a good
indication of this type of fault. A strip down and application of some
silicone grease to the o ring should get it working properly.


--

"Matt" wrote in message
...
On 24 Nov 2005 03:28:10 -0800, "urchaidh" wrote:


I have a new Pegler tap fitted with conventional washers. When the cold
is turned on it starts just fine then dwindles away to nothing in about
5s. Further opening of the tap restores the flow.

Any idea what could cause this? Is it likely to be the tap washer
and/or is my tinkering with the stopcock setting ill advised? I even
wondered if it was a design feature of the tap, attempting to give a
consistent flow across variable mains pressure, and failing.

Either the water pressure is too low or more likely it's the o ring
sealing the spindle to the tap upper body which is either displaced or
hanging up due to lack of lubrication. If the flow changes when you
either press down or lift the tap handle then this is usually a good
indication of this type of fault. A strip down and application of some
silicone grease to the o ring should get it working properly.


--
I think it could be due to the reduced flow set by the stop tap. The
pressure is the same and the whole system is acting as a pressure vessel.
When the tap is opened this initial pressure is released - you are then down
to relying on the reduced flow rate set by the stop tap.



--
John

john wrote in message
news

"Matt" wrote in message
...
On 24 Nov 2005 03:28:10 -0800, "urchaidh" wrote:


I have a new Pegler tap fitted with conventional washers. When the cold
is turned on it starts just fine then dwindles away to nothing in about
5s. Further opening of the tap restores the flow.

Any idea what could cause this? Is it likely to be the tap washer
and/or is my tinkering with the stopcock setting ill advised? I even
wondered if it was a design feature of the tap, attempting to give a
consistent flow across variable mains pressure, and failing.

Either the water pressure is too low or more likely it's the o ring
sealing the spindle to the tap upper body which is either displaced or
hanging up due to lack of lubrication. If the flow changes when you
either press down or lift the tap handle then this is usually a good
indication of this type of fault. A strip down and application of some
silicone grease to the o ring should get it working properly.


--
I think it could be due to the reduced flow set by the stop tap. The
pressure is the same and the whole system is acting as a pressure vessel.
When the tap is opened this initial pressure is released - you are then
down
to relying on the reduced flow rate set by the stop tap.

The pressure in a hydraulic system is the same at all places. There can't be
an initial surge of pressure over and above whatever is being supplied all
the time by the mains pipe.
--
Dave Baker

In an earlier contribution to this discussion,
Dave Baker wrote:

--
I think it could be due to the reduced flow set by the stop tap. The
pressure is the same and the whole system is acting as a pressure
vessel. When the tap is opened this initial pressure is released -
you are then down to relying on the reduced flow rate set by the
stop tap.

The pressure in a hydraulic system is the same at all places. There
can't be an initial surge of pressure over and above whatever is
being supplied all the time by the mains pipe.

I think he's suggesting that there may be some compressibility in the
system - acting like a small accummulator, and that this is charged up to
mains pressure and provides some initial flow. Once the stored energy has
been released, the remaining flow is limited to what the partially-closed
stoptap can deliver.
--
Cheers,
Set Square
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Set Square wrote:
In an earlier contribution to this discussion,
Dave Baker wrote:
I think it could be due to the reduced flow set by the stop tap. The
pressure is the same and the whole system is acting as a pressure
vessel....
The pressure in a hydraulic system is the same at all places. ...

I think he's suggesting that there may be some compressibility in the
system - acting like a small accummulator

I hope not!! Water is pretty much uncompressible so for the above to
be the case there would need to be something pretty weird going on in
my pipework.

Thanks for all the advice though, will have a look at the tap washer
and a tinker with the stopcock this evening.

urchaidh wrote:

I hope not!! Water is pretty much uncompressible so for the above to
be the case there would need to be something pretty weird going on in
my pipework.

Washing machine or dishwasher hose is good at this

Lee
--
Email address is valid, but is unlikely to be read.

Chris Bacon wrote:

I've has a similar problem. The washer sits in a cup attached to
the "jumper":

I had something with similar symptoms on a hot bath tap. The flow from
the hot tap was much less than the flow from the cold.

It turned out to be a bit of foam insulation from the hot water
storage cylinder inside the pipe. The foam floated on the hot water and
obstructed the inlet to the tap. However, on isolating and draining the
hot water in the kitchen below, the water level dropped and the foam
vanished from sight. Many others had tried in vain to find the mystery
blockage.

I only found it because my first attempt failed. I only drained it at
the adjacent basin, so there was still a trickle of water coming from
the tap when I dismantled it again and the foam was still visible.

This sounds like it might be something that sinks and is normally lying
in the horizontal run below the sink. On turning on the water, the flow
lifts the blockage until, about 5 seconds later, it obstructs the tap.
I'd disconnect the pipe, connect it to a large bore pipe or hose and
blast some into a bucket.

Then again, it might be something completely different.

In an earlier contribution to this discussion,
urchaidh wrote:

Set Square wrote:
In an earlier contribution to this discussion,
I think he's suggesting that there may be some compressibility in the
system - acting like a small accummulator

I hope not!! Water is pretty much uncompressible so for the above to
be the case there would need to be something pretty weird going on in
my pipework.

Water may not be compressible - but trapped air is. Besides which, there can
be stretchy bits - like washing machine hoses - as someone else has pointed
out.
--
Cheers,
Set Square
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