We recently had a replacement bathroom fitted and the taps keep slowly
dripping for several minutes after they're turned off.

The taps are of the single lever monodisc type, with a ceramic
cartridge. The bathroom company has replaced the cartridge and now the
taps themselves too, but nothing changes.

My understanding is that taps of this type need balanced water supplies,
but we have the cold supply fed from the rising main and the hot is
gravity fed from the loft tank. Clearly there is nothing like balanced
pressure at the taps and you can see evidence of that by looking at the
different flow rates for hot & cold water.

Could this imbalance be the explanation for the dripping ? What are the
usual problems caused by unequal pressure ? The bathroom fitters are
adamant that these taps are suitable and insist that they have never had
a problem like this before, even with similar feed arrangements.

Obviously a solution is needed and one possible solution might be a
pressure reduction valve. Is it likely to do the trick and would it be
appropriate to have just one valve fitted in the pipe coming up to the
bathroom rather than one PRV per tap ?

I saw monobloc kitchen tap for sale in Lidyl at an exceptionaly good price
and wanted to buy. My brother who is a plumber said not to do so as I would
get a problm similar to what you are describing.
He said that most of these taps are made for untits with combi boilers when
the pressure of both hot and cold are the same. I have a mains fed cold
supply to my sink but the hot is from a traditional hot water system
(cistern in loft) so the pressures cannot match. The other problem is the
very small bore of the pipe into the tap; this may not be a problem for you
if you get a good enought flow from the hot on its own.
In my bathroom I changed the flow from the mains to that of the roof cistern
and then fitted a pressure activated pump so both hot and cold now match.
It might work fitting a pressure reduction valve on the mains supply but I
doubt it.


"Roly" wrote in message
...
We recently had a replacement bathroom fitted and the taps keep slowly
dripping for several minutes after they're turned off.

The taps are of the single lever monodisc type, with a ceramic
cartridge. The bathroom company has replaced the cartridge and now the
taps themselves too, but nothing changes.

My understanding is that taps of this type need balanced water supplies,
but we have the cold supply fed from the rising main and the hot is
gravity fed from the loft tank. Clearly there is nothing like balanced
pressure at the taps and you can see evidence of that by looking at the
different flow rates for hot & cold water.

Could this imbalance be the explanation for the dripping ? What are the
usual problems caused by unequal pressure ? The bathroom fitters are
adamant that these taps are suitable and insist that they have never had
a problem like this before, even with similar feed arrangements.

Obviously a solution is needed and one possible solution might be a
pressure reduction valve. Is it likely to do the trick and would it be
appropriate to have just one valve fitted in the pipe coming up to the
bathroom rather than one PRV per tap ?

"Stewart" wrote in message
...
I saw monobloc kitchen tap for sale in Lidyl at an exceptionaly good price
and wanted to buy. My brother who is a plumber said not to do so as I
would get a problm similar to what you are describing.
He said that most of these taps are made for untits with combi boilers
when the pressure of both hot and cold are the same. I have a mains fed
cold supply to my sink but the hot is from a traditional hot water system
(cistern in loft) so the pressures cannot match. The other problem is the
very small bore of the pipe into the tap; this may not be a problem for
you if you get a good enought flow from the hot on its own.
In my bathroom I changed the flow from the mains to that of the roof
cistern and then fitted a pressure activated pump so both hot and cold now
match.
It might work fitting a pressure reduction valve on the mains supply but I
doubt it.


I thought it was illegal to fit a mixer where the hot and cold actually
mixed before the outlet.
None of the taps I have seen for sale have any common path shared by the hot
and cold and the pressure difference is irrelevant.

On 26/02/2008 13:39, dennis@home wrote:

I thought it was illegal to fit a mixer where the hot and cold actually
mixed before the outlet.

a one-way valve is recommended

None of the taps I have seen for sale have any common path shared by the
hot and cold and the pressure difference is irrelevant.

Most of the newish ones I've seen *are* like that, I had to track down a
Franke one that had a "coaxial" spout and mixed at the outlet.

"Andy Burns" wrote in message
...
On 26/02/2008 13:39, dennis@home wrote:

I thought it was illegal to fit a mixer where the hot and cold actually
mixed before the outlet.

a one-way valve is recommended

None of the taps I have seen for sale have any common path shared by the
hot and cold and the pressure difference is irrelevant.

Most of the newish ones I've seen *are* like that, I had to track down a
Franke one that had a "coaxial" spout and mixed at the outlet.

Something must have changed then, I don't buy many mixer taps. ;-)

On Tue, 26 Feb 2008 13:39:41 -0000, "dennis@home"
wrote:



"Stewart" wrote in message
...
I saw monobloc kitchen tap for sale in Lidyl at an exceptionaly good price
and wanted to buy. My brother who is a plumber said not to do so as I
would get a problm similar to what you are describing.
He said that most of these taps are made for untits with combi boilers
when the pressure of both hot and cold are the same. I have a mains fed
cold supply to my sink but the hot is from a traditional hot water system
(cistern in loft) so the pressures cannot match. The other problem is the
very small bore of the pipe into the tap; this may not be a problem for
you if you get a good enought flow from the hot on its own.
In my bathroom I changed the flow from the mains to that of the roof
cistern and then fitted a pressure activated pump so both hot and cold now
match.
It might work fitting a pressure reduction valve on the mains supply but I
doubt it.


I thought it was illegal to fit a mixer where the hot and cold actually
mixed before the outlet.
None of the taps I have seen for sale have any common path shared by the hot
and cold and the pressure difference is irrelevant.


I've got a monoblock fitted in my kitchen - don't know what make it is
( picked it up at the local tip for a fiver ) but it's obviously a
well-made bit of kit.
Cold water is at mains pressure, hot is gravity fed - so there's a
substantial difference in pressure, and I get no leaks at all.
The unit has small bore tails, and separate paths down the outlet (
the cold water form a rather nice latticework effect ).

Regards,



--
Stephen Howard - Woodwind repairs & period restorations
www.shwoodwind.co.uk
Emails to: showard{whoisat}shwoodwind{dot}co{dot}uk

On Feb 26, 2:04*pm, Stephen Howard wrote:
On Tue, 26 Feb 2008 13:39:41 -0000, "dennis@home"





wrote:

"Stewart" wrote in message
...
I saw monobloc kitchen tap for sale in Lidyl at an exceptionaly good price
and wanted to buy. *My brother who is a plumber said not to do so as I
would get a problm similar to what you are describing.
He said that most of these taps are made for untits with combi boilers
when the pressure of both hot and cold are the same. *I have a mains fed
cold supply to my sink but the hot is from a traditional hot water system
(cistern in loft) so the pressures cannot match. *The other problem is the
very small bore of the pipe into the tap; this may not be a problem for
you if you get a good enought flow from the hot on its own.
In my bathroom I changed the flow from the mains to that of the roof
cistern and then fitted a pressure activated pump so both hot and cold now
match.
It might work fitting a pressure reduction valve on the mains supply but I
doubt it.

I thought it was illegal to fit a mixer where the hot and cold actually
mixed before the outlet.
None of the taps I have seen for sale have any common path shared by the hot
and cold and the pressure difference is irrelevant.

I've got a monoblock fitted in my kitchen - don't know what make it is
( picked it up at the local tip for a fiver ) but it's obviously a
well-made bit of kit.
Cold water is at mains pressure, hot is gravity fed - so there's a
substantial difference in pressure, and I get no leaks at all.
The unit has small bore tails, and separate paths down the outlet (
the cold water form a rather nice latticework effect ).

Regards,

--
Stephen Howard - Woodwind repairs & period restorationswww.shwoodwind.co.uk
Emails to: showard{whoisat}shwoodwind{dot}co{dot}uk- Hide quoted text -

- Show quoted text -

Have you got a pair of filters in the feeds to the taps to keep out
any small bits of crap in the water. Just wondered as i know if they
start leeking there a bugger to fix.

Gaz

On Tue, 26 Feb 2008 13:39:41 -0000, "dennis@home"
wrote:




I thought it was illegal to fit a mixer where the hot and cold actually
mixed before the outlet.
None of the taps I have seen for sale have any common path shared by the hot
and cold and the pressure difference is irrelevant.



Dennis is corrct - if the water mixes at the outlet the pressure won't
make any difference. Ours has been working successfully for 10years,
with tank hot and mains cold water. No drips or other turn off
problems. Its the kitchen sink tap and is used frequently.

On 26 Feb, 13:33, "Stewart" wrote:
I saw monobloc kitchen tap for sale in Lidyl at an exceptionaly good price
and wanted to buy. *My brother who is a plumber said not to do so as I would
get a problm similar to what you are describing.
He said that most of these taps are made for untits with combi boilers when
the pressure of both hot and cold are the same.

I bought the Lidl one (£15), as the £100+ "high quality" Pegler one
that I bought was useless in terms of hot water flow (gravity fed from
hot water cylinder) - and yes, I did check that there was no flow
restrictor or mesh filter, and I changed the flexible hose for a wide-
bore version).

The Lidl one works perfectly - and it does not drip.

CRB

On Tue, 26 Feb 2008 06:16:48 -0800 (PST), Garry
wrote:


Have you got a pair of filters in the feeds to the taps to keep out
any small bits of crap in the water. Just wondered as i know if they
start leeking there a bugger to fix.

Didn't notice any filters on mine - and given that the hot water comes
via a Rayburn it's probably a problem waiting to happen!

Regards,



--
Stephen Howard - Woodwind repairs & period restorations
http://www.shwoodwind.co.uk
Emails to: showard{who is at}shwoodwind{dot}co{dot}uk

I gather that the dripping probably isn't caused by unbalanced water
pressure. Why do the manufacturers insist that balanced supplies are
used ?

What can be expected to happen if the supplies are unbalanced ? Is it
merely the danger that water can cross-contiminate the other supply or
is there another reason ?

replying to Roly, Quintar verbum wrote:
In my case cold water from the mains pushed its way up the hot water pipe and
caused the water level in my attic tanks to rise and overflow (via overflow
pipe, but also cause minor internal leaks). It only happened when we were away
for a few days. During daily use it never rose to a problem level, and hence
was missed.
Now I need to find a kitchen monobloc mixer that does not mix in the body of
tap, but instead has separate paths as earlier poster described. I think they
are less common now.

--
for full context, visit https://www.homeownershub.com/uk-diy...re-461683-.htm