we have a saunier duval thelia 23 combi boiler- at the moment the
pressure needs refilling every couple of hours or so. there's no
clearly visible water on any of the valves/connections, or the outside
overflow pipe. plumbers after expensive brief looks say it must be a
leak in pipework and do no tests on actual boiler. we'd be happy to
pay to get pipework done, but are hesitant as the same problem was
fixed on this system 2 years ago with work on the boiler alone- but we
have no paperwork to contact the company/individual who did the job.
is there anything we can do to be *really* sure it is a leak in the
pipework and not the boiler?
any friendly reliable plumbers in camden/islington/holloway rd area?

eternally grateful for any response...
helenski x

"helenski" wrote in message
om...
we have a saunier duval thelia 23 combi boiler- at the moment the
pressure needs refilling every couple of hours or so. there's no
clearly visible water on any of the valves/connections, or the outside
overflow pipe. plumbers after expensive brief looks say it must be a
leak in pipework and do no tests on actual boiler. we'd be happy to
pay to get pipework done, but are hesitant as the same problem was
fixed on this system 2 years ago with work on the boiler alone- but we
have no paperwork to contact the company/individual who did the job.
is there anything we can do to be *really* sure it is a leak in the
pipework and not the boiler?
any friendly reliable plumbers in camden/islington/holloway rd area?

eternally grateful for any response...
helenski x

Have a look at the overpressure blowoff pipe ( the overflow pipe ) again,
but do so when the system fires up, as it may be that there is a problem
with your expansion vessel ( regulates the system pressure when the water
gets hot ). I would imagine that another way to tell if this was he problem
would be to watch the pressure gauge when the system ( i.e. the central
heating ) comes on. As the CH water is heated, if the pressure gauge creeps
up
to 2.4 or 3 bar ( depending on what type of overpressure valve you have ),
and
then zooms down to a low figure all of a sudden, that'll be the overpressure
valve opening and venting water outside ( at great velocity ).

Otherwise it sounds like you have a leak somewhere, but it must be
fairly
big to lose system pressure so quickly. Beware the fact that if the CH water
is very
hot when it leaks, it may evaporate and not cause a puddle. have you
examined
all the CH piping yourself, even under the floor?

Andy.

"andrewpreece" wrote in message
...

"helenski" wrote in message
om...
we have a saunier duval thelia 23 combi boiler- at the moment the
pressure needs refilling every couple of hours or so. there's no
clearly visible water on any of the valves/connections, or the outside
overflow pipe. plumbers after expensive brief looks say it must be a
leak in pipework and do no tests on actual boiler. we'd be happy to
pay to get pipework done, but are hesitant as the same problem was
fixed on this system 2 years ago with work on the boiler alone- but we
have no paperwork to contact the company/individual who did the job.
is there anything we can do to be *really* sure it is a leak in the
pipework and not the boiler?
any friendly reliable plumbers in camden/islington/holloway rd area?

eternally grateful for any response...
helenski x

Have a look at the overpressure blowoff pipe ( the overflow pipe ) again,
but do so when the system fires up, as it may be that there is a problem
with your expansion vessel ( regulates the system pressure when the water
gets hot ). I would imagine that another way to tell if this was he
problem
would be to watch the pressure gauge when the system ( i.e. the central
heating ) comes on. As the CH water is heated, if the pressure gauge
creeps
up
to 2.4 or 3 bar ( depending on what type of overpressure valve you have ),
and
then zooms down to a low figure all of a sudden, that'll be the
overpressure
valve opening and venting water outside ( at great velocity ).

Otherwise it sounds like you have a leak somewhere, but it must be
fairly
big to lose system pressure so quickly. Beware the fact that if the CH
water
is very
hot when it leaks, it may evaporate and not cause a puddle. have you
examined
all the CH piping yourself, even under the floor?


If the mains pipe is a low pressure 1 bar, then the system water will work
its way into the mains if the plate heat exchanger is holed. Sometimes the
water out of the tap is brown or tastes bad.

thanks very much;
but do so when the system fires up, as it may be that there is a problem
with your expansion vessel
plumbers have checked this out- and refilled the expansion vessel.
also i have observed pressure while turning on, off, and anything in
between -i really don't think it hits anything high enough, or has
dramatic enough drop to be the overpressure valve as described.
at the moment, starting with the system at zero, when switched on, the
pressure will not rise at all - until manually filled - and then falls
gradually (but very quickly) from that moment on. we're filling it
*many* times a day now.

hot when it leaks, it may evaporate and not cause a puddle. have you
examined all the CH piping yourself, even under the floor?
no- have examined anything visible as best as possible, but trying to
investigate everything about the boiler before taking up
floorboards/concrete. if that really needs doing then we'll go down
that route as cheerily as possible- my reluctance is based on the fact
that previous engineer stopped the very same thing from happening by
fiddling with the boiler only (very technical, i know..)
now we are getting a little bit of wetness on the pipes near the 'tap'
where we fill the pressure up. but we can't see if/where it is coming
from, and it seems to appear at random.
well, any more ideas very welcome!
helenski x

On Wed, 18 Feb 2004 05:45:04 +0000, helenski wrote:

we have a saunier duval thelia 23 combi boiler- at the moment the
pressure needs refilling every couple of hours or so. there's no
clearly visible water on any of the valves/connections, or the outside
overflow pipe. plumbers after expensive brief looks say it must be a
leak in pipework and do no tests on actual boiler. we'd be happy to
pay to get pipework done, but are hesitant as the same problem was
fixed on this system 2 years ago with work on the boiler alone- but we
have no paperwork to contact the company/individual who did the job.
is there anything we can do to be *really* sure it is a leak in the
pipework and not the boiler?
any friendly reliable plumbers in camden/islington/holloway rd area?

eternally grateful for any response...
helenski x

Firstly read the FAQ below.

If you are filling up that often then you do have a leak somewhere and if
it were anywhere visible you would know about it.
If it were in the boiler itself it would only be a short while before the
boiler was dripping wet.

I presume that there could be some places where there is pipework where a
big leak could go undetected?

I presume the work that was done 2 years ago was to fix a leaking pressure
releif valve or was it to fix some sort of leak inside the boler?

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at 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

On Wed, 18 Feb 2004 13:03:17 +0000, helenski wrote:

thanks very much;
but do so when the system fires up, as it may be that there is a problem
with your expansion vessel
plumbers have checked this out- and refilled the expansion vessel.
also i have observed pressure while turning on, off, and anything in
between -i really don't think it hits anything high enough, or has
dramatic enough drop to be the overpressure valve as described.
at the moment, starting with the system at zero, when switched on, the
pressure will not rise at all - until manually filled - and then falls
gradually (but very quickly) from that moment on. we're filling it
*many* times a day now.

OK you have a big leak somewhere.


hot when it leaks, it may evaporate and not cause a puddle. have you
examined all the CH piping yourself, even under the floor?
no- have examined anything visible as best as possible, but trying to
investigate everything about the boiler before taking up
floorboards/concrete. if that really needs doing then we'll go down
that route as cheerily as possible- my reluctance is based on the fact
that previous engineer stopped the very same thing from happening by
fiddling with the boiler only (very technical, i know..)
now we are getting a little bit of wetness on the pipes near the 'tap'
where we fill the pressure up. but we can't see if/where it is coming
from, and it seems to appear at random.

This could be condensation because the pipes will be at around 10C on
account of the mains cold water coming in.



well, any more ideas very welcome!

I presume you have something like a ground floor flat with a wood floor?
So you could be putting a lot of water down there under the floor with
any problems.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at 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

"helenski" wrote in message
om...
we have a saunier duval thelia 23 combi boiler- at the moment the
pressure needs refilling every couple of hours or so. there's no
clearly visible water on any of the valves/connections, or the outside
overflow pipe. plumbers after expensive brief looks say it must be a
leak in pipework and do no tests on actual boiler. we'd be happy to
pay to get pipework done, but are hesitant as the same problem was
fixed on this system 2 years ago with work on the boiler alone- but we
have no paperwork to contact the company/individual who did the job.
is there anything we can do to be *really* sure it is a leak in the
pipework and not the boiler?
any friendly reliable plumbers in camden/islington/holloway rd area?

eternally grateful for any response...
helenski x

I've just had a similar problem on a 2 y.o system. It turned out to be a
faulty/leaking heat exchange coil in the indirect water cylinder.
--
©J.Milton.Hayes©


---
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On Wed, 18 Feb 2004 23:32:58 +0000, J.Milton.Hayes wrote:


"helenski" wrote in message
om...
we have a saunier duval thelia 23 combi boiler- at the moment the
pressure needs refilling every couple of hours or so. there's no
clearly visible water on any of the valves/connections, or the outside
overflow pipe. plumbers after expensive brief looks say it must be a
leak in pipework and do no tests on actual boiler. we'd be happy to
pay to get pipework done, but are hesitant as the same problem was
fixed on this system 2 years ago with work on the boiler alone- but we
have no paperwork to contact the company/individual who did the job.
is there anything we can do to be *really* sure it is a leak in the
pipework and not the boiler?
any friendly reliable plumbers in camden/islington/holloway rd area?

eternally grateful for any response...
helenski x

I've just had a similar problem on a 2 y.o system. It turned out to be a
faulty/leaking heat exchange coil in the indirect water cylinder.

However this is a combi boiler so that can't happen here.
If the DHW heat exchanger is holed then the pressure would rise to mains
pressure which is at least 1 bar+ and likely 3 bar+


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at 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

Pleeeese help meeee........

I have the same problem but,

I have a constant drip from the overflow pipe and this increases when I turn on the boiler for heating the rads.
I am having to fill the boiler and I have tried to drain air from all the rads but to avail.
There is a small amount of what could be condensation under the boiler, not that much. It seems that this happens at the onset of winter.
Any help would be appreciated.