Had a Saunier Duval combi boiler (non condensing) fitted ~4 year ago as part
of a large extension. The existing pipes and radiators were left untouched,
but quite a few new ones were added to the system to cover the new rooms
that were added. It is a single zone system, so all the pipes/radiators are
now part of the same circuit (or whatever you call it).

I will try to describe the problem giving as much detail as possible:

- The pressure of the system is dropping all the time. Initially I had to
top it up every few months, but the frequency has gradually escalated. Last
winter it was down to once every couple of weeks, so far this year I had to
do it every couple of days or so. Not ideal, I know, but see below why we
decided to try and live with it.
- I set it to around 1.2-1.4 and top it up again when it drops to 0.7-0.8.
The system cuts off when it goes down to 0.6 (it has a digital display).
- The pressure seem to only drop after the heating has been running for a
while, and remains pretty stable for a long time (days/weeks/months) if no
heating is used.
- The pressure seem to drop almost immediately (i.e. after running the
heating once) to 0.9 or 0.8, but then stays there for a while (again,
days/weeks/months) until eventually it drops to 0.7 or so where I have to
top it up again.

The house is a 2 floor detached with suspended floor that can be easily
access from below - around 1m height under the house..

My obvious suspicion was a leak, however:

- There is no noticeable sign of it on any of the ceilings
- Unfortunately all the new part of the house (around a 3rd of it) is
inaccessible from below at all, and has solid oak flooring that I would
rather nor rip...

Any idea what is going on here based on the above? Anything I can try
before I go under to inspect the accessible part? It is horrible in there...

May thanks in advance.

PS: The boiler and new pipes/radiators were fitted by the most incompetent
plumbers I have ever come across (and I have done up 10+ houses as a side
business over the last few years, so I have seen many pretty closely). Ass
the builder we hired brought them with him we haven't had much say in the
matter, and most of the problems only became apparent late on. Every single
thing they touched failed within days or weeks at most, and we were so
concerned that we ended up calling Corgi who sent an inspector to verify
that it was at least not dangerous. It wasn't apparently, but they were so
lazy that they left 1m of 15mm gas pipe that should have been upgraded to
22mm along the way that they had to come back and do.

On 18 Oct, 16:04, "JoeJoe" wrote:
Had a Saunier Duval combi boiler (non condensing) fitted ~4 year ago as part
of a large extension. The existing pipes and radiators were left untouched,
but quite a few new ones were added to the system to cover the new rooms
that were added. It is a single zone system, so all the pipes/radiators are
now part of the same circuit (or whatever you call it).

I will try to describe the problem giving as much detail as possible:

- The pressure of the system is dropping all the time. Initially I had to
top it up every few months, but the frequency has gradually escalated. Last
winter it was down to once every couple of weeks, so far this year I had to
do it every couple of days or so. Not ideal, I know, but see below why we
decided to try and live with it.
- I set it to around 1.2-1.4 and top it up again when it drops to 0.7-0.8..
The system cuts off when it goes down to 0.6 (it has a digital display).
- The pressure seem to only drop after the heating has been running for a
while, and remains pretty stable for a long time (days/weeks/months) if no
heating is used.
- The pressure seem to drop almost immediately (i.e. after running the
heating once) to 0.9 or 0.8, but then stays there for a while (again,
days/weeks/months) until eventually it drops to 0.7 or so where I have to
top it up again.

The house is a 2 floor detached with suspended floor that can be easily
access from below - around 1m height under the house..

My obvious suspicion was a leak, however:

- There is no noticeable sign of it on any of the ceilings
- Unfortunately all the new part of the house (around a 3rd of it) is
inaccessible from below at all, and has solid oak flooring that I would
rather nor rip...

Any idea what is going on here based on the above? *Anything I can try
before I go under to inspect the accessible part? It is horrible in there....

May thanks in advance.

PS: *The boiler and new pipes/radiators were fitted by the most incompetent
plumbers I have ever come across (and I have done up 10+ houses as a side
business over the last few years, so I have seen many pretty closely). Ass
the builder we hired brought them with him we haven't had much say in the
matter, and most of the problems only became apparent late on. Every single
thing they touched failed within days or weeks at most, and we were so
concerned that we ended up calling Corgi who sent an inspector to verify
that it was at least not dangerous. It wasn't apparently, but they were so
lazy that they left 1m of 15mm gas pipe that should have been upgraded to
22mm along the way that they had to come back and do.

Obviously there is a leak. I assume you have made sure the safety/
relief valve is not leaking. Outlet from it normally goes outside the
house. It will be by the boiler. Check there are no drips from
this.Check for wetness on carpets under radiators.

If you can't see the leak, it's obviously in an awkward place. The
most likely being where the pipes are buried in the floor. Cement
will attack copper pipes unless they are protected. Normally this
shows up as a wet patch but if you have wooden floors, these might
conceal it.
Unfortunately you have to go round &find out where the leak isn't.
Which will leave just few expensive to check places where it must be.
Make sure it's not the boiler itself leaking, sometimes this is not
immediately apparent.

In message
,
harry writes
On 18 Oct, 16:04, "JoeJoe" wrote:
Had a Saunier Duval combi boiler (non condensing) fitted ~4 year ago as part
of a large extension. The existing pipes and radiators were left untouched,
but quite a few new ones were added to the system to cover the new rooms
that were added. It is a single zone system, so all the pipes/radiators are
now part of the same circuit (or whatever you call it).

I will try to describe the problem giving as much detail as possible:

- The pressure of the system is dropping all the time. Initially I had to
top it up every few months, but the frequency has gradually escalated. Last
winter it was down to once every couple of weeks, so far this year I had to
do it every couple of days or so. Not ideal, I know, but see below why we
decided to try and live with it.

We had exactly this after a recent move to a combi from a thermal store,
this meant running the CH at mains pressure, so I was pleasantly
surprised when nothing leaked.

Well, for two weeks.

Then the pressure started dropping, it needed a daily top up. We have
wooden floors downstairs and upstairs mainly laminate. I was dreading
ripping up any floors but closer examination of the downstairs it looked
like the pipes run in the walls and not the floor at all. Three days
later and directly above the TV the very recently plastered ceiling
turned brown. Oh well - easily fixed - ripped up the laminate in the en
suite to find that the towel rail was just plastic fittings and one was
leaking. Took it apart, cleaned it and re-assembled and it's been fine
since (although I haven't put the laminate back just in case). Might be
worth checking any plastic fittings if you have any, sods law it'll be
in the floor though.


--
Mike Buckley
RD350LC2
XJ900S

harry wrote:

On 18 Oct, 16:04, "JoeJoe" wrote:

- The pressure of the system is dropping all the time. Initially I had to
top it up every few months, but the frequency has gradually escalated.
Last winter it was down to once every couple of weeks, so far this year I
had to do it every couple of days or so. Not ideal, I know, but see below
why we decided to try and live with it.
- I set it to around 1.2-1.4 and top it up again when it drops to
0.7-0.8. The system cuts off when it goes down to 0.6 (it has a digital
display). - The pressure seem to only drop after the heating has been
running for a while, and remains pretty stable for a long time
(days/weeks/months) if no heating is used.
- The pressure seem to drop almost immediately (i.e. after running the
heating once) to 0.9 or 0.8, but then stays there for a while (again,
days/weeks/months) until eventually it drops to 0.7 or so where I have to
top it up again.

The house is a 2 floor detached with suspended floor that can be easily
access from below - around 1m height under the house..

My obvious suspicion was a leak, however:

- There is no noticeable sign of it on any of the ceilings
- Unfortunately all the new part of the house (around a 3rd of it) is
inaccessible from below at all, and has solid oak flooring that I would
rather nor rip...

Obviously there is a leak. I assume you have made sure the safety/
relief valve is not leaking. Outlet from it normally goes outside the
house. It will be by the boiler. Check there are no drips from
this.Check for wetness on carpets under radiators.

I suspect he hasn't looked at the relief outlet. The symptoms, especially
the fact that it has been gradually getting worse, and that it then happens
after the first heating) strongly suggest that the expansion vessel has lost
its air, so that when the heating goes on, the pressure caused by the
expanding water causes the relief valve to operate. Once it cools down, the
lack of air in the expansion vessel means there's nothing to keep the
pressure at normal levels, so it drops.

The usual fix involves using a bicycle pump.

What amount of water am looking for for such a leak? a cup-full? litters? a
few drops?

When if the best time to try and spot it? Top the system up, turn it on,
and then look?


"harry" wrote in message
...
On 18 Oct, 16:04, "JoeJoe" wrote:
Had a Saunier Duval combi boiler (non condensing) fitted ~4 year ago as
part
of a large extension. The existing pipes and radiators were left
untouched,
but quite a few new ones were added to the system to cover the new rooms
that were added. It is a single zone system, so all the pipes/radiators
are
now part of the same circuit (or whatever you call it).

I will try to describe the problem giving as much detail as possible:

- The pressure of the system is dropping all the time. Initially I had to
top it up every few months, but the frequency has gradually escalated.
Last
winter it was down to once every couple of weeks, so far this year I had
to
do it every couple of days or so. Not ideal, I know, but see below why we
decided to try and live with it.
- I set it to around 1.2-1.4 and top it up again when it drops to 0.7-0.8.
The system cuts off when it goes down to 0.6 (it has a digital display).
- The pressure seem to only drop after the heating has been running for a
while, and remains pretty stable for a long time (days/weeks/months) if no
heating is used.
- The pressure seem to drop almost immediately (i.e. after running the
heating once) to 0.9 or 0.8, but then stays there for a while (again,
days/weeks/months) until eventually it drops to 0.7 or so where I have to
top it up again.

The house is a 2 floor detached with suspended floor that can be easily
access from below - around 1m height under the house..

My obvious suspicion was a leak, however:

- There is no noticeable sign of it on any of the ceilings
- Unfortunately all the new part of the house (around a 3rd of it) is
inaccessible from below at all, and has solid oak flooring that I would
rather nor rip...

Any idea what is going on here based on the above? Anything I can try
before I go under to inspect the accessible part? It is horrible in
there...

May thanks in advance.

PS: The boiler and new pipes/radiators were fitted by the most incompetent
plumbers I have ever come across (and I have done up 10+ houses as a side
business over the last few years, so I have seen many pretty closely). Ass
the builder we hired brought them with him we haven't had much say in the
matter, and most of the problems only became apparent late on. Every
single
thing they touched failed within days or weeks at most, and we were so
concerned that we ended up calling Corgi who sent an inspector to verify
that it was at least not dangerous. It wasn't apparently, but they were so
lazy that they left 1m of 15mm gas pipe that should have been upgraded to
22mm along the way that they had to come back and do.

Obviously there is a leak. I assume you have made sure the safety/
relief valve is not leaking. Outlet from it normally goes outside the
house. It will be by the boiler. Check there are no drips from
this.Check for wetness on carpets under radiators.

If you can't see the leak, it's obviously in an awkward place. The
most likely being where the pipes are buried in the floor. Cement
will attack copper pipes unless they are protected. Normally this
shows up as a wet patch but if you have wooden floors, these might
conceal it.
Unfortunately you have to go round &find out where the leak isn't.
Which will leave just few expensive to check places where it must be.
Make sure it's not the boiler itself leaking, sometimes this is not
immediately apparent.

"Ronald Raygun" wrote in message
...
harry wrote:

On 18 Oct, 16:04, "JoeJoe" wrote:

- The pressure of the system is dropping all the time. Initially I had
to
top it up every few months, but the frequency has gradually escalated.
Last winter it was down to once every couple of weeks, so far this year
I
had to do it every couple of days or so. Not ideal, I know, but see
below
why we decided to try and live with it.
- I set it to around 1.2-1.4 and top it up again when it drops to
0.7-0.8. The system cuts off when it goes down to 0.6 (it has a digital
display). - The pressure seem to only drop after the heating has been
running for a while, and remains pretty stable for a long time
(days/weeks/months) if no heating is used.
- The pressure seem to drop almost immediately (i.e. after running the
heating once) to 0.9 or 0.8, but then stays there for a while (again,
days/weeks/months) until eventually it drops to 0.7 or so where I have
to
top it up again.

The house is a 2 floor detached with suspended floor that can be easily
access from below - around 1m height under the house..

My obvious suspicion was a leak, however:

- There is no noticeable sign of it on any of the ceilings
- Unfortunately all the new part of the house (around a 3rd of it) is
inaccessible from below at all, and has solid oak flooring that I would
rather nor rip...

Obviously there is a leak. I assume you have made sure the safety/
relief valve is not leaking. Outlet from it normally goes outside the
house. It will be by the boiler. Check there are no drips from
this.Check for wetness on carpets under radiators.

I suspect he hasn't looked at the relief outlet. The symptoms, especially
the fact that it has been gradually getting worse, and that it then
happens
after the first heating) strongly suggest that the expansion vessel has
lost
its air, so that when the heating goes on, the pressure caused by the
expanding water causes the relief valve to operate. Once it cools down,
the
lack of air in the expansion vessel means there's nothing to keep the
pressure at normal levels, so it drops.

The usual fix involves using a bicycle pump.

Anything I can do myself to check this, or should I phone someone to look at
it?

On Oct 19, 1:35*pm, "JoeJoe" wrote:
"Ronald Raygun" wrote in message

...





harry wrote:

On 18 Oct, 16:04, "JoeJoe" wrote:

- The pressure of the system is dropping all the time. Initially I had
to
top it up every few months, but the frequency has gradually escalated..
Last winter it was down to once every couple of weeks, so far this year
I
had to do it every couple of days or so. Not ideal, I know, but see
below
why we decided to try and live with it.
- I set it to around 1.2-1.4 and top it up again when it drops to
0.7-0.8. The system cuts off when it goes down to 0.6 (it has a digital
display). - The pressure seem to only drop after the heating has been
running for a while, and remains pretty stable for a long time
(days/weeks/months) if no heating is used.
- The pressure seem to drop almost immediately (i.e. after running the
heating once) to 0.9 or 0.8, but then stays there for a while (again,
days/weeks/months) until eventually it drops to 0.7 or so where I have
to
top it up again.

The house is a 2 floor detached with suspended floor that can be easily
access from below - around 1m height under the house..

My obvious suspicion was a leak, however:

- There is no noticeable sign of it on any of the ceilings
- Unfortunately all the new part of the house (around a 3rd of it) is
inaccessible from below at all, and has solid oak flooring that I would
rather nor rip...

Obviously there is a leak. I assume you have made sure the safety/
relief valve is not leaking. Outlet from it normally goes outside the
house. It will be by the boiler. Check there are no drips from
this.Check for wetness on carpets under radiators.

I suspect he hasn't looked at the relief outlet. *The symptoms, especially
the fact that it has been gradually getting worse, and that it then
happens
after the first heating) strongly suggest that the expansion vessel has
lost
its air, so that when the heating goes on, the pressure caused by the
expanding water causes the relief valve to operate. *Once it cools down,
the
lack of air in the expansion vessel means there's nothing to keep the
pressure at normal levels, so it drops.

The usual fix involves using a bicycle pump.

Anything I can do myself to check this, or should I phone someone to look at
it?



I suggest:

(1) drain water until the pressure stops falling, then (2) pump the
accumulator with air up (bike pump or car foot pump) to about 0.5 Bar,
then (3) fill with water back up to the usual working pressure. i
expect others will be along later with the correct figure for the
'slack' pressure. if this fixes the problem then all is well.

Robert

JoeJoe wrote:

"Ronald Raygun" wrote in message
...

I suspect he hasn't looked at the relief outlet. The symptoms,
especially the fact that it has been gradually getting worse, and that it
then happens
after the first heating) strongly suggest that the expansion vessel has
lost
its air, so that when the heating goes on, the pressure caused by the
expanding water causes the relief valve to operate. Once it cools down,
the
lack of air in the expansion vessel means there's nothing to keep the
pressure at normal levels, so it drops.

The usual fix involves using a bicycle pump.

Anything I can do myself to check this, or should I phone someone to look
at it?

Find the relief outlet. Normally the pipe goes through the outside wall
and protrudes a few inches form the wall. When the relief valve operates,
you should see a drip from there, but it might not be obvious. When the
system is cold, put a dry bucket under it. Then pressurise the system and
turn the heater on for an hour or so. Then see whether there's any water
in the bucket.

On 18 Oct, 18:39, Ronald Raygun wrote:
harry wrote:
Obviously there is a leak.

I suspect he hasn't looked at the relief outlet. *The symptoms, especially
the fact that it has been gradually getting worse, and that it then happens
after the first heating) strongly suggest that the expansion vessel has lost
its air, so that when the heating goes on, the pressure caused by the
expanding water causes the relief valve to operate.

Indeed, that's my guess too. The "obviously a leak" diagnosis is more
than likely completely wrong.

Richard.
http://www.rtrussell.co.uk/

"JoeJoe" wrote in message
o.uk...
What amount of water am looking for for such a leak? a cup-full? litters?
a few drops?

When if the best time to try and spot it? Top the system up, turn it on,
and then look?



For the pressure to drop visibly, you must be loosing cupfulls (cupsfull?).

But if you tape a poly bag over the overflow pipe you will easily spot
fractions of a teaspoon.