[Grumps[_5_]]

Hello

We've got a 28 yr old Potterton conventional gas boiler serving a hot water
cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the water.
It has kettled for a few years, but this boiling is a new development.
The British Gas man (we have maintenance on this old thing) said it was most
likely sludged up either in the HE or pipework around the boiler, and thus
the water is not circulating fast enough so it boils.
I thought we had a Y-plan system but can't seem to figure out the pipes in
the airing cupboard. I have posted a picture he
http://i56.tinypic.com/2vnj638.jpg
Physically the boiler is in the direction of the arrow shown.
"This looks like it comes from the boiler" is a pipe that goes to the coil
of the HW cylinder.
"This doesn't go to the boiler" is a pipe that doesn't appear to be in the
direction of said boiler and connects to the base of the pump.
I was expecting the hot from the boiler to go to the base of the pump!
I know it's difficult looking at just this one picture, but can anyone
explain if it is correct?
Ta.

[TheScullster]

"Grumps" wrote


We've got a 28 yr old Potterton conventional gas boiler serving a hot
water cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the
water. It has kettled for a few years, but this boiling is a new
development.
The British Gas man (we have maintenance on this old thing) said it was
most likely sludged up either in the HE or pipework around the boiler, and
thus the water is not circulating fast enough so it boils.
I thought we had a Y-plan system but can't seem to figure out the pipes in
the airing cupboard. I have posted a picture he
http://i56.tinypic.com/2vnj638.jpg
Physically the boiler is in the direction of the arrow shown.
"This looks like it comes from the boiler" is a pipe that goes to the coil
of the HW cylinder.
"This doesn't go to the boiler" is a pipe that doesn't appear to be in the
direction of said boiler and connects to the base of the pump.
I was expecting the hot from the boiler to go to the base of the pump!
I know it's difficult looking at just this one picture, but can anyone
explain if it is correct?
Ta.


Hi Grumps

Like you I would expect the boiler feed to be at the base of the pump.
The pipe heading towards the cylinder from the valve would be the central
heating feed.
The pipe heading away from the cylinder from the valve IYSWIM then tees down
(via some strange elbow arrangement) to the top cylinder connection; and
tees up to a reduced 15mm pipe - is this the cold water make up for the
heating circuit?
At this age it's likely to be vented with a loft header tank?
It would depend on the piping layout, but with our system (prior to re-work)
there was a serious build up of crud around a motorised valve and at the
vent/liquid interface. It could be that you have a similar issue and the
restricted vent is causing the boiler to pressurise a little.
Have you replaced any piping/valves to know the general condition/cruddiness
of the internals?
Have you kept a reasonable concentration of inhibitor in the system?
Have you ever flushed the system out (either chemical or power flush)?

Having had an old boiler replaced with a modern condensing jobbie, I would
hang on to the old girl as long as possible.
New models are far too complex for their own good IMHO.

Phil

[Grumps[_5_]]

"TheScullster" wrote in message
. uk...

"Grumps" wrote


We've got a 28 yr old Potterton conventional gas boiler serving a hot
water cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the
water. It has kettled for a few years, but this boiling is a new
development.
The British Gas man (we have maintenance on this old thing) said it was
most likely sludged up either in the HE or pipework around the boiler,
and thus the water is not circulating fast enough so it boils.
I thought we had a Y-plan system but can't seem to figure out the pipes
in the airing cupboard. I have posted a picture he
http://i56.tinypic.com/2vnj638.jpg
Physically the boiler is in the direction of the arrow shown.
"This looks like it comes from the boiler" is a pipe that goes to the
coil of the HW cylinder.
"This doesn't go to the boiler" is a pipe that doesn't appear to be in
the direction of said boiler and connects to the base of the pump.
I was expecting the hot from the boiler to go to the base of the pump!
I know it's difficult looking at just this one picture, but can anyone
explain if it is correct?
Ta.


Hi Grumps

Like you I would expect the boiler feed to be at the base of the pump.
The pipe heading towards the cylinder from the valve would be the central
heating feed.
The pipe heading away from the cylinder from the valve IYSWIM then tees
down (via some strange elbow arrangement) to the top cylinder connection;
and tees up to a reduced 15mm pipe - is this the cold water make up for
the heating circuit?
At this age it's likely to be vented with a loft header tank?
It would depend on the piping layout, but with our system (prior to
re-work) there was a serious build up of crud around a motorised valve and
at the vent/liquid interface. It could be that you have a similar issue
and the restricted vent is causing the boiler to pressurise a little.
Have you replaced any piping/valves to know the general
condition/cruddiness of the internals?
Have you kept a reasonable concentration of inhibitor in the system?
Have you ever flushed the system out (either chemical or power flush)?

Having had an old boiler replaced with a modern condensing jobbie, I would
hang on to the old girl as long as possible.
New models are far too complex for their own good IMHO.

Hi Phil

Ta for reply.

The strange elbow arrangement was my plumber's best attempt at fitting a
replacement cyclinder many years ago. The new couplings didn't line up with
the exiting pipework. The tee up to a 15mm pipe is for the bathroom rad
which is in the hot water circuit.

Yes, vented with a loft header tank.

The vent was coupled with the cold feed about 10 years ago due to another
blockage. So the cold feed is through the vent pipe. This, apparently, is
quite normal as a 'bodge' to give it some more years.

The system was drained but not power flushed about 4 years ago. The last
bits of water out were dark coloured. It was refilled and inhibitor added
then.

I'm sure people will have their opinions on the new(?) condensing units, but
have you reason to suspect that they'll not last as long?
According to Mr B.Gas, we'd save about £450 a year if we put in a new
A-rated boiler. According to my calculations, if my boiler can be brought
back to its peak performance of 65%, then a 91% efficient boiler would save
us £186/year. I think 91% is the max listed in sedbuk.
It'll take a good few years to recover the costs involved in a boiler
replacement, TRVs, flue re-positioning (it's too close to a window), etc.

Is it possible to just power flush the boiler and close-to pipes?

[Grumps[_5_]]

"Grumps" wrote in message
...
Hello

We've got a 28 yr old Potterton conventional gas boiler serving a hot
water cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the
water. It has kettled for a few years, but this boiling is a new
development.
The British Gas man (we have maintenance on this old thing) said it was
most likely sludged up either in the HE or pipework around the boiler, and
thus the water is not circulating fast enough so it boils.
I thought we had a Y-plan system but can't seem to figure out the pipes in
the airing cupboard. I have posted a picture he
http://i56.tinypic.com/2vnj638.jpg
Physically the boiler is in the direction of the arrow shown.
"This looks like it comes from the boiler" is a pipe that goes to the coil
of the HW cylinder.
"This doesn't go to the boiler" is a pipe that doesn't appear to be in the
direction of said boiler and connects to the base of the pump.
I was expecting the hot from the boiler to go to the base of the pump!
I know it's difficult looking at just this one picture, but can anyone
explain if it is correct?
Ta.

Oh, and the other thing was that the BG man put a "do not use sticker" on it
due to the fact that hot/warm water is getting into the header tank and
making it, er, warm - which appraently it's not designed to do.
The risk being that the tank deforms and splits and the water comes out
which will be replaced by fresh water from the ball-cock. I could of course
do big bodge #2 and direct the vent to the overflow thus disposing of the
hot/warm water outside.

[funkyoldcortina]

On 01/06/11 14:44, Grumps wrote:
wrote in message
...
Hello

We've got a 28 yr old Potterton conventional gas boiler serving a hot
water cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the
water. It has kettled for a few years, but this boiling is a new
development.
The British Gas man (we have maintenance on this old thing) said it was
most likely sludged up either in the HE or pipework around the boiler, and
thus the water is not circulating fast enough so it boils.
I thought we had a Y-plan system but can't seem to figure out the pipes in
the airing cupboard. I have posted a picture he
http://i56.tinypic.com/2vnj638.jpg
Physically the boiler is in the direction of the arrow shown.
"This looks like it comes from the boiler" is a pipe that goes to the coil
of the HW cylinder.
"This doesn't go to the boiler" is a pipe that doesn't appear to be in the
direction of said boiler and connects to the base of the pump.
I was expecting the hot from the boiler to go to the base of the pump!
I know it's difficult looking at just this one picture, but can anyone
explain if it is correct?
Ta.

Oh, and the other thing was that the BG man put a "do not use sticker" on it
due to the fact that hot/warm water is getting into the header tank and
making it, er, warm - which appraently it's not designed to do.
The risk being that the tank deforms and splits and the water comes out
which will be replaced by fresh water from the ball-cock.

If that happens the never-ending supply of cold water coming from the ball
cock will only be a minor comfort to anyone who happened to be under a split
tankful of boiling water pouring through the ceiling onto them...

People have been killed in this circumstance.

[Grumps[_5_]]

"funkyoldcortina" wrote in message
...
On 01/06/11 14:44, Grumps wrote:
wrote in message
...
Hello

We've got a 28 yr old Potterton conventional gas boiler serving a hot
water cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the
water. It has kettled for a few years, but this boiling is a new
development.
The British Gas man (we have maintenance on this old thing) said it was
most likely sludged up either in the HE or pipework around the boiler,
and
thus the water is not circulating fast enough so it boils.
I thought we had a Y-plan system but can't seem to figure out the pipes
in
the airing cupboard. I have posted a picture he
http://i56.tinypic.com/2vnj638.jpg
Physically the boiler is in the direction of the arrow shown.
"This looks like it comes from the boiler" is a pipe that goes to the
coil
of the HW cylinder.
"This doesn't go to the boiler" is a pipe that doesn't appear to be in
the
direction of said boiler and connects to the base of the pump.
I was expecting the hot from the boiler to go to the base of the pump!
I know it's difficult looking at just this one picture, but can anyone
explain if it is correct?
Ta.

Oh, and the other thing was that the BG man put a "do not use sticker" on
it
due to the fact that hot/warm water is getting into the header tank and
making it, er, warm - which appraently it's not designed to do.
The risk being that the tank deforms and splits and the water comes out
which will be replaced by fresh water from the ball-cock.

If that happens the never-ending supply of cold water coming from the ball
cock will only be a minor comfort to anyone who happened to be under a
split tankful of boiling water pouring through the ceiling onto them...

People have been killed in this circumstance.

I'm not sure. I thought the only deaths have been due to the main cold water
tank boiling, not the boiler header tank. I could be wrong though.
Anyway, there's only a gallon in the header tank, and if it split then the
contents would end up in the airing cupboard. Almost as if it were designed
that way to be safe!

[Mike Tomlinson]

In article , Grumps
writes

Oh, and the other thing was that the BG man put a "do not use sticker" on it
due to the fact that hot/warm water is getting into the header tank and
making it, er, warm - which appraently it's not designed to do.

BG man did the right thing.

The tank might fill with very hot/boiling water which will soften it and
if/when it collapses, that water will then come crashing through the
ceiling onto some luckless person below. A toddler died some years ago
when this happened.

http://news.bbc.co.uk/1/hi/england/somerset/7175037.stm
http://www.hse.gov.uk/services/local...tersystems.htm

--
Mike Tomlinson

[Roger Mills[_2_]]

On 01/06/2011 12:15, Grumps wrote:
Hello

We've got a 28 yr old Potterton conventional gas boiler serving a hot water
cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the water.
It has kettled for a few years, but this boiling is a new development.
The British Gas man (we have maintenance on this old thing) said it was most
likely sludged up either in the HE or pipework around the boiler, and thus
the water is not circulating fast enough so it boils.
I thought we had a Y-plan system but can't seem to figure out the pipes in
the airing cupboard. I have posted a picture he
http://i56.tinypic.com/2vnj638.jpg
Physically the boiler is in the direction of the arrow shown.
"This looks like it comes from the boiler" is a pipe that goes to the coil
of the HW cylinder.
"This doesn't go to the boiler" is a pipe that doesn't appear to be in the
direction of said boiler and connects to the base of the pump.
I was expecting the hot from the boiler to go to the base of the pump!
I know it's difficult looking at just this one picture, but can anyone
explain if it is correct?
Ta.


The pipe connected to the base of the pump *must* go to the boiler. It's
almost certainly the main flow pipe - going on to the 3-port valve which
splits the flow into two circuits - HW circuit going into the top of the
cylinder coil, and CH circuit going down under the floor to the
radiators. The returns from the HW and CH circuits will combine
somewhere under the floorboards, and go back to the boiler.

Even if everything is the wrong way round - with the pump and valve on
the return rather than flow side, the pipe beneath the pump will *still*
go to the boiler - but will be the return rather than the flow. Which
way is the arrow on the pump?

Are you sure that the pump is working? That would be my first port of
call if the boiler is boiling due to insufficient flow.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

[Grumps[_5_]]

"Mike Tomlinson" wrote in message
...
In article , Grumps
writes

Oh, and the other thing was that the BG man put a "do not use sticker" on
it
due to the fact that hot/warm water is getting into the header tank and
making it, er, warm - which appraently it's not designed to do.

BG man did the right thing.

Indeed. That is his job which he executed perfectly. No complaints.

The tank might fill with very hot/boiling water which will soften it and
if/when it collapses, that water will then come crashing through the
ceiling onto some luckless person below. A toddler died some years ago
when this happened.

http://news.bbc.co.uk/1/hi/england/somerset/7175037.stm
http://www.hse.gov.uk/services/local...tersystems.htm

Yes, very sad.
Not the same situation here though. That poor child died as a resuilt of the
water tank containing the boiling water. In my case, it'll only be the
boiler header tank. This holds about a gallon and sits above the airing
cupboard.

[Grumps[_5_]]

"Roger Mills" wrote in message
...
On 01/06/2011 12:15, Grumps wrote:
Hello

We've got a 28 yr old Potterton conventional gas boiler serving a hot
water
cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the
water.
It has kettled for a few years, but this boiling is a new development.
The British Gas man (we have maintenance on this old thing) said it was
most
likely sludged up either in the HE or pipework around the boiler, and
thus
the water is not circulating fast enough so it boils.
I thought we had a Y-plan system but can't seem to figure out the pipes
in
the airing cupboard. I have posted a picture he
http://i56.tinypic.com/2vnj638.jpg
Physically the boiler is in the direction of the arrow shown.
"This looks like it comes from the boiler" is a pipe that goes to the
coil
of the HW cylinder.
"This doesn't go to the boiler" is a pipe that doesn't appear to be in
the
direction of said boiler and connects to the base of the pump.
I was expecting the hot from the boiler to go to the base of the pump!
I know it's difficult looking at just this one picture, but can anyone
explain if it is correct?
Ta.


The pipe connected to the base of the pump *must* go to the boiler. It's
almost certainly the main flow pipe - going on to the 3-port valve which
splits the flow into two circuits - HW circuit going into the top of the
cylinder coil, and CH circuit going down under the floor to the radiators.
The returns from the HW and CH circuits will combine somewhere under the
floorboards, and go back to the boiler.

Ta, yes.
I've had a much bigger look with the torch and feeling under the boards with
my fingers. Indeed the pipe going to the bottom of the pump comes from the
boiler. There's a short loop under the floor which doubles back and makes it
look like the pump pipe goes the wrong way.

Even if everything is the wrong way round - with the pump and valve on the
return rather than flow side, the pipe beneath the pump will *still* go to
the boiler - but will be the return rather than the flow. Which way is the
arrow on the pump?

The pump's arrow points up. So everything is as I originally expected.

Are you sure that the pump is working? That would be my first port of call
if the boiler is boiling due to insufficient flow.

The pump sounds like it is whirring when required, and the speed switch
seems to change the whirring sound. When central heating is switched on
(just for testing), all rads get nice and toasty. Maybe if the three-port
valve is stuck somehow, that might slow the water flow. But would that also
make the pump sound like its struggling?

If I disconnect the pipe at the base of the pump, and have access to the
cold feed and vent pipes, doesn't this mean I can isolate the boiler and do
a separate power flush on just the boiler?

[TheScullster]

"Grumps" wrote

"Grumps" wrote


We've got a 28 yr old Potterton conventional gas boiler serving a hot
water cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the
water. It has kettled for a few years, but this boiling is a new
development.
The British Gas man (we have maintenance on this old thing) said it was
most likely sludged up either in the HE or pipework around the boiler,
and thus the water is not circulating fast enough so it boils.
I thought we had a Y-plan system but can't seem to figure out the pipes
in the airing cupboard. I have posted a picture he
http://i56.tinypic.com/2vnj638.jpg
Physically the boiler is in the direction of the arrow shown.
"This looks like it comes from the boiler" is a pipe that goes to the
coil of the HW cylinder.
"This doesn't go to the boiler" is a pipe that doesn't appear to be in
the direction of said boiler and connects to the base of the pump.
I was expecting the hot from the boiler to go to the base of the pump!
I know it's difficult looking at just this one picture, but can anyone
explain if it is correct?
Ta.


Hi Grumps

Like you I would expect the boiler feed to be at the base of the pump.
The pipe heading towards the cylinder from the valve would be the central
heating feed.
The pipe heading away from the cylinder from the valve IYSWIM then tees
down (via some strange elbow arrangement) to the top cylinder connection;
and tees up to a reduced 15mm pipe - is this the cold water make up for
the heating circuit?
At this age it's likely to be vented with a loft header tank?
It would depend on the piping layout, but with our system (prior to
re-work) there was a serious build up of crud around a motorised valve
and at the vent/liquid interface. It could be that you have a similar
issue and the restricted vent is causing the boiler to pressurise a
little.
Have you replaced any piping/valves to know the general
condition/cruddiness of the internals?
Have you kept a reasonable concentration of inhibitor in the system?
Have you ever flushed the system out (either chemical or power flush)?

Having had an old boiler replaced with a modern condensing jobbie, I
would hang on to the old girl as long as possible.
New models are far too complex for their own good IMHO.

Hi Phil

Ta for reply.

The strange elbow arrangement was my plumber's best attempt at fitting a
replacement cyclinder many years ago. The new couplings didn't line up
with the exiting pipework. The tee up to a 15mm pipe is for the bathroom
rad which is in the hot water circuit.

Yes, vented with a loft header tank.

The vent was coupled with the cold feed about 10 years ago due to another
blockage. So the cold feed is through the vent pipe. This, apparently, is
quite normal as a 'bodge' to give it some more years.

Provided that the vent is 22mm not just the 15mm (usual make up water feed
size).


The system was drained but not power flushed about 4 years ago. The last
bits of water out were dark coloured. It was refilled and inhibitor added
then.

I'm sure people will have their opinions on the new(?) condensing units,
but have you reason to suspect that they'll not last as long?

I had a Worcester Bosch system boiler fitted in 2006 - still using a vented
system.
The only problems so far have been due to the plumbers not setting up the
auto bypass valve properly and the boiler constantly over-running the pump
as a result. That and the varying casing noise caused by the oscillating
fan levels.
Basically they are exactly what you would expect of modern technology -
built with loads of lights, gizmos and sensors (plenty to go wrong) and
minimum material thickness etc.


According to Mr B.Gas, we'd save about £450 a year if we put in a new
A-rated boiler. According to my calculations, if my boiler can be brought
back to its peak performance of 65%, then a 91% efficient boiler would
save us £186/year. I think 91% is the max listed in sedbuk.

If the boiler is in a room that benefits from the heat loss from your
current boiler then the figures are further exaggerated.
Our boiler is in the kitchen, so (for most of the year) heat lost from the
boiler is useful and not lost "efficiency".

It'll take a good few years to recover the costs involved in a boiler
replacement, TRVs, flue re-positioning (it's too close to a window), etc.

Is it possible to just power flush the boiler and close-to pipes?

It may be worth chemical flushing by running the system with cleaner
yourself for a couple of weeks (Fernox tech support v good).

On the subject of warm header tanks, my understanding is that they are
likely to get warm via the action of expansion. As long as you don't have
pump-over via the vent then some warmth in the header tank is usual.

Phil

[Mr Pounder[_2_]]

"Grumps" wrote in message
...
Hello

We've got a 28 yr old Potterton conventional gas boiler serving a hot
water cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the
water. It has kettled for a few years, but this boiling is a new
development.
The British Gas man (we have maintenance on this old thing) said it was
most likely sludged up either in the HE or pipework around the boiler, and
thus the water is not circulating fast enough so it boils.
I thought we had a Y-plan system but can't seem to figure out the pipes in
the airing cupboard. I have posted a picture he
http://i56.tinypic.com/2vnj638.jpg
Physically the boiler is in the direction of the arrow shown.
"This looks like it comes from the boiler" is a pipe that goes to the coil
of the HW cylinder.
"This doesn't go to the boiler" is a pipe that doesn't appear to be in the
direction of said boiler and connects to the base of the pump.
I was expecting the hot from the boiler to go to the base of the pump!
I know it's difficult looking at just this one picture, but can anyone
explain if it is correct?
Ta.

We have full cover with British Gas, wife's idea not mine.
If the rads or boiler are ****ed BG replace.
Take a look at your policy.
Then argue the toss with the *******s.

[cynic]

On Jun 1, 12:15*pm, "Grumps" wrote:
Hello

We've got a 28 yr old Potterton conventional gas boiler serving a hot water
cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the water.

[Roger Mills[_2_]]

On 01/06/2011 17:10, Grumps wrote:
"Roger wrote in message
...


Are you sure that the pump is working? That would be my first port of call
if the boiler is boiling due to insufficient flow.

The pump sounds like it is whirring when required, and the speed switch
seems to change the whirring sound. When central heating is switched on
(just for testing), all rads get nice and toasty. Maybe if the three-port
valve is stuck somehow, that might slow the water flow. But would that also
make the pump sound like its struggling?

It's not uncommon for the impeller to part company from the shaft - so
the motor whirrs but it doesn't pump any water. Having said that, if the
rads get hot, it suggests that the pump *is* working. Does this boiling
problem only occur when you're just heating the HW, with the CH switched
off? If so, there could be a blockage in the HW circuit. there were one
or things I couldn't quite make out in your photo. Is there a manual
gate valve in one of the pipes to the cylinder coil, to balance the HW &
CH circuits? If so, could that be closed up too much?

If I disconnect the pipe at the base of the pump, and have access to the
cold feed and vent pipes, doesn't this mean I can isolate the boiler and do
a separate power flush on just the boiler?

It depends where the fill and vent pipes are connected into the system.
Mine are both teed into the flow pipe just under the pump, and so only
give access to *one* side of the boiler.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

[geoff]

In message , Mr Pounder
writes


We have full cover with British Gas, wife's idea not mine.
If the rads or boiler are ****ed BG replace.

Unless they can find a get out clause of any sort

Take a look at your policy.
Then argue the toss with the *******s.

Better to go elsewhere and not have the hassle


--
geoff

[harry]

On Jun 1, 12:15*pm, "Grumps" wrote:
Hello

We've got a 28 yr old Potterton conventional gas boiler serving a hot water
cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the water.

[Grumps[_5_]]

"Roger Mills" wrote in message
...
On 01/06/2011 17:10, Grumps wrote:
"Roger wrote in message
...


Are you sure that the pump is working? That would be my first port of
call
if the boiler is boiling due to insufficient flow.

The pump sounds like it is whirring when required, and the speed switch
seems to change the whirring sound. When central heating is switched on
(just for testing), all rads get nice and toasty. Maybe if the three-port
valve is stuck somehow, that might slow the water flow. But would that
also
make the pump sound like its struggling?

It's not uncommon for the impeller to part company from the shaft - so the
motor whirrs but it doesn't pump any water. Having said that, if the rads
get hot, it suggests that the pump *is* working. Does this boiling problem
only occur when you're just heating the HW, with the CH switched off?

Yes.

If so, there could be a blockage in the HW circuit. there were one or
things I couldn't quite make out in your photo. Is there a manual gate
valve in one of the pipes to the cylinder coil, to balance the HW & CH
circuits? If so, could that be closed up too much?

No, no manual gate valve. Just a poor photo.

If I disconnect the pipe at the base of the pump, and have access to the
cold feed and vent pipes, doesn't this mean I can isolate the boiler and
do
a separate power flush on just the boiler?

It depends where the fill and vent pipes are connected into the system.
Mine are both teed into the flow pipe just under the pump, and so only
give access to *one* side of the boiler.

Hmm, I'll have to investigate my pipes some more.
Thanks.

[Grumps[_5_]]

"Mr Pounder" wrote in message
...

"Grumps" wrote in message
...
Hello

We've got a 28 yr old Potterton conventional gas boiler serving a hot
water cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the
water. It has kettled for a few years, but this boiling is a new
development.
The British Gas man (we have maintenance on this old thing) said it was
most likely sludged up either in the HE or pipework around the boiler,
and thus the water is not circulating fast enough so it boils.
I thought we had a Y-plan system but can't seem to figure out the pipes
in the airing cupboard. I have posted a picture he
http://i56.tinypic.com/2vnj638.jpg
Physically the boiler is in the direction of the arrow shown.
"This looks like it comes from the boiler" is a pipe that goes to the
coil of the HW cylinder.
"This doesn't go to the boiler" is a pipe that doesn't appear to be in
the direction of said boiler and connects to the base of the pump.
I was expecting the hot from the boiler to go to the base of the pump!
I know it's difficult looking at just this one picture, but can anyone
explain if it is correct?
Ta.

We have full cover with British Gas, wife's idea not mine.
If the rads or boiler are ****ed BG replace.
Take a look at your policy.
Then argue the toss with the *******s.

Interesting. What cover do you have? I have my policy in front of me. It has
a few clauses including:
1) If broken boiler is less than 7 years old they'll fit a new one.
2) If older than 7 years then they'll give you a 5% discount off the cost of
an new installation if they can't repair it, as long as BG do it.
3) Your first power flush has to be paid for. Subsequent ones are free.
That's from the Homecare T&Cs.

[Grumps[_5_]]

"cynic" wrote in message
...
On Jun 1, 12:15 pm, "Grumps" wrote:
Hello

We've got a 28 yr old Potterton conventional gas boiler serving a hot
water
cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the
water.
It has kettled for a few years, but this boiling is a new development.
The British Gas man (we have maintenance on this old thing) said it was
most
likely sludged up either in the HE or pipework around the boiler, and thus
the water is not circulating fast enough so it boils.
I thought we had a Y-plan system but can't seem to figure out the pipes in
the airing cupboard. I have posted a picture
hehttp://i56.tinypic.com/2vnj638.jpg
Physically the boiler is in the direction of the arrow shown.
"This looks like it comes from the boiler" is a pipe that goes to the coil
of the HW cylinder.
"This doesn't go to the boiler" is a pipe that doesn't appear to be in the
direction of said boiler and connects to the base of the pump.
I was expecting the hot from the boiler to go to the base of the pump!
I know it's difficult looking at just this one picture, but can anyone
explain if it is correct?
Ta.

You could try some "boiler noise silencer" gel to deal with the
kettling, and you should also check the boiler thermostat is working.
When these get old and tired they often do not switch the heat off at
the original set temperature but their calibration drifts, Welded
contacts in the 'stat are another possibility. A replacement stat is
significantly cheaper than a new boiler by a couple of orders of
magnitude

OK. Any idea what this stat looks like? I guess it's mechanical and
connected to my front panel dial in some way.

[Grumps[_5_]]

"harry" wrote in message
...
On Jun 1, 12:15 pm, "Grumps" wrote:
Hello

We've got a 28 yr old Potterton conventional gas boiler serving a hot
water
cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the
water.
It has kettled for a few years, but this boiling is a new development.
The British Gas man (we have maintenance on this old thing) said it was
most
likely sludged up either in the HE or pipework around the boiler, and thus
the water is not circulating fast enough so it boils.
I thought we had a Y-plan system but can't seem to figure out the pipes in
the airing cupboard. I have posted a picture
hehttp://i56.tinypic.com/2vnj638.jpg
Physically the boiler is in the direction of the arrow shown.
"This looks like it comes from the boiler" is a pipe that goes to the coil
of the HW cylinder.
"This doesn't go to the boiler" is a pipe that doesn't appear to be in the
direction of said boiler and connects to the base of the pump.
I was expecting the hot from the boiler to go to the base of the pump!
I know it's difficult looking at just this one picture, but can anyone
explain if it is correct?
Ta.

If your BG man thinks there's crud in the pipes/boiler, why did he not
flush it out?

Because they charge £700 for the flushing service! They don't do a freebie
anymore.

If your boiler is overheating there are only a few possible causes.

The boiler thermostat is naff. (permanently closed/on.)
The boiler is full of crud.

I'm sure that is certainly true.Several years ago I changed a rad and the
system wouldn't re-fill. That's when BG joined the cold feed and vent
together.

Sufficient water is not being circulated through the boiler.
A combination of these.

How do I test the boiler stat? If the boiler is hot and I turn the stat to
min, it still runs. Is that a good indicator of a faulty stat?

By messing with the theromstat and the pump speed you should be able
to determine which. See which pipes are getting hot. Radiator/hot
water.
Are the control valves working?

The only control valve I have is the 3-port valve. Is this what you mean?
Ta.

[cynic]

On Jun 1, 11:04*pm, "Grumps" wrote:
"cynic" wrote in message

...
On Jun 1, 12:15 pm, "Grumps" wrote:





Hello

We've got a 28 yr old Potterton conventional gas boiler serving a hot
water
cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the
water.
It has kettled for a few years, but this boiling is a new development.
The British Gas man (we have maintenance on this old thing) said it was
most
likely sludged up either in the HE or pipework around the boiler, and thus
the water is not circulating fast enough so it boils.
I thought we had a Y-plan system but can't seem to figure out the pipes in
the airing cupboard. I have posted a picture
hehttp://i56.tinypic.com/2vnj638.jpg
Physically the boiler is in the direction of the arrow shown.
"This looks like it comes from the boiler" is a pipe that goes to the coil
of the HW cylinder.
"This doesn't go to the boiler" is a pipe that doesn't appear to be in the
direction of said boiler and connects to the base of the pump.
I was expecting the hot from the boiler to go to the base of the pump!
I know it's difficult looking at just this one picture, but can anyone
explain if it is correct?
Ta.

You could try some "boiler noise silencer" gel to deal with the
kettling, and you should also check the boiler thermostat is working.
When these get old and tired they often do not switch the heat off at
the original set temperature but their calibration drifts, Welded
contacts in the 'stat are another possibility. A replacement stat is
significantly cheaper than a new boiler by a couple of orders of
magnitude

OK. Any idea what this stat looks like? I guess it's mechanical and
connected to my front panel dial in some way.- Hide quoted text -

- Show quoted text -

the thermostat "works" is behind the adjustment dial and there will be
a thin capillary tube with a vial on the end which tucks into the
boiler shell, usually in front at the top but sometimes further back.
Some boilers have an overheat stat as well although this is often a
manual reset device.

[Roger Mills[_2_]]

On 01/06/2011 23:10, Grumps wrote:


How do I test the boiler stat? If the boiler is hot and I turn the stat to
min, it still runs. Is that a good indicator of a faulty stat?


Yes - either that or a wiring fault which is effectively short
circuiting the stat.

To test it properly you need to remove it from the boiler (pull the bulb
at the end of the copper capilliary tube out of its pocket in the heat
exchanger, and disconnect the wires (making a careful note of the
connections!).

You then need to dunk the bulb in an old saucepan of water on a gas or
electric hob so that you can vary the water temperature - and,
preferably, also measure it with a mercury in glass thermometer - and
check whether the electrical contacts open and close when you would
expect them to for various knob settings.
--
Cheers,
Roger
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