We have just had a new worcester bosch system boiler fitted to a fully
pumped system. In the night we heard lots of noise from all the pipework and
the radiators so i went in the loft today to check something and found the
header tank which tops up the system has quite hot water in it !!

is this normal? i suspect not

what could this be caused by?

apart from the noise which only seems to happen at night, everything seems
ok

cheers

Daz

ps. it has just been converted to a standard Y plan system because we had
no independant control over the hot water so they added a 3-way valve

additional information

i have just watched the system and noted as soon as the demand for the
heating goes off , the pump seems to flow all the hot water into the header
tank in the loft for about 5-10 seconds. The tank then seems to go back to
its correct level.

Is it when the valve is changeing state?

if so, what can i do?


"dbroms" wrote in message
...
We have just had a new worcester bosch system boiler fitted to a fully
pumped system. In the night we heard lots of noise from all the pipework
and the radiators so i went in the loft today to check something and found
the header tank which tops up the system has quite hot water in it !!

is this normal? i suspect not

what could this be caused by?

apart from the noise which only seems to happen at night, everything seems
ok

cheers

Daz

ps. it has just been converted to a standard Y plan system because we
had no independant control over the hot water so they added a 3-way valve

"dbroms" wrote in message
...

We have just had a new worcester bosch system boiler fitted to a fully
pumped system.

System boilers do not have header tanks.

In the night we heard lots of noise from all the pipework and
the radiators so i went in the loft today to check something and found the
header tank which tops up the system has quite hot water in it !!

is this normal? i suspect not

what could this be caused by?

apart from the noise which only seems to happen at night, everything seems
ok

Check that air is out of the system.

"dbroms" wrote in message
...
additional information

i have just watched the system and noted as soon as the demand for the
heating goes off , the pump seems to flow all the hot water into the
header
tank in the loft for about 5-10 seconds. The tank then seems to go back to
its correct level.

Is it when the valve is changeing state?

if so, what can i do?

Describe the system. Mid-position valve? pumps on the flow or return?
Cylinder? etc.

System boilers do not have header tanks

mine has definately got a header tank. The valve is a honeywell 3 position
diverter valve. The tank has a built in header tank that supplies cold water
to be heated up and the other header is in the loft which tops up the sealed
heated water that flows through the coil in the tank unless i have it
totally wrong.



"Doctor Drivel" wrote in message
reenews.net...

"dbroms" wrote in message
...

We have just had a new worcester bosch system boiler fitted to a fully
pumped system.

System boilers do not have header tanks.

In the night we heard lots of noise from all the pipework and
the radiators so i went in the loft today to check something and found
the
header tank which tops up the system has quite hot water in it !!

is this normal? i suspect not

what could this be caused by?

apart from the noise which only seems to happen at night, everything
seems
ok

Check that air is out of the system.

In an earlier contribution to this discussion,
dbroms wrote:

System boilers do not have header tanks

mine has definately got a header tank. The valve is a honeywell 3
position diverter valve. The tank has a built in header tank that
supplies cold water to be heated up and the other header is in the
loft which tops up the sealed heated water that flows through the
coil in the tank unless i have it totally wrong.

Well, something is definitely not right!

Your primary circulation system is either vented or unvented (sealed).

If unvented, there is no header tank - by definition - but there is a
pressure vessel instead, to allow for expansion, and a filling loop to allow
the system to be initially filled with water.

If vented, there is a fill & expansion tank - but no pressure vessel or
filling loop.

The term 'system boiler' is usually associated with a sealed/pressurised
system - which has an expansion vessel - and often a pump also - inside the
boiler casing.

So a slightly more detailed description of your system would be helpful.
--
Cheers,
Set Square
______
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my system has just been converted by installing a diverter valve to
hopefully allow me to select heating OR ho****er.
I have had fitted a worcester bosch condensing (non combi hence system)
boiler. The pump has a tee piece straight after it, one pipe goes to an open
pipe just above the water line in a header tank in the loft and the other
goes to AB connection on the 3 way valve.
It is definately vented , no fill loop or pressure vessels.

do u require anymore info?
"Set Square" wrote in message
...
In an earlier contribution to this discussion,
dbroms wrote:

System boilers do not have header tanks

mine has definately got a header tank. The valve is a honeywell 3
position diverter valve. The tank has a built in header tank that
supplies cold water to be heated up and the other header is in the
loft which tops up the sealed heated water that flows through the
coil in the tank unless i have it totally wrong.

Well, something is definitely not right!

Your primary circulation system is either vented or unvented (sealed).

If unvented, there is no header tank - by definition - but there is a
pressure vessel instead, to allow for expansion, and a filling loop to
allow
the system to be initially filled with water.

If vented, there is a fill & expansion tank - but no pressure vessel or
filling loop.

The term 'system boiler' is usually associated with a sealed/pressurised
system - which has an expansion vessel - and often a pump also - inside
the
boiler casing.

So a slightly more detailed description of your system would be helpful.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

"dbroms" wrote in message
...
my system has just been converted by installing a diverter valve to
hopefully allow me to select heating OR ho****er.
I have had fitted a worcester bosch condensing (non combi hence system)

A system boiler has a pump and pressure vessel inside, you have a "heating"
boiler.

boiler. The pump has a tee piece straight after it, one pipe goes to an
open
pipe just above the water line in a header tank in the loft and the other
goes to AB connection on the 3 way valve.
It is definately vented , no fill loop or pressure vessels.

Does the boiler have a pump overrun? If so that is a problem here. Where
does the 15mm feed pipe from the F&E tank go to? It is best to have this
fill the system just before the tee after the pump, So, boiler flow -
pump - tee to F&E tank (feed) - directly after another tee that goes to
the open vent over the F&E tank - the diverter valve. This will prevent
pump over.

The diverter de-energises to either CH or DHW port open. Any pump overrun
should go though this port, not over the F&E tank, Having the feed and open
vent pipe teed off next to each other put equal pressure on each. The feed
tee MUST be nearest the boiler.

In an earlier contribution to this discussion,
dbroms wrote:

my system has just been converted by installing a diverter valve to
hopefully allow me to select heating OR ho****er.
I have had fitted a worcester bosch condensing (non combi hence
system) boiler. The pump has a tee piece straight after it, one pipe
goes to an open pipe just above the water line in a header tank in
the loft and the other goes to AB connection on the 3 way valve.
It is definately vented , no fill loop or pressure vessels.

do u require anymore info?

AIUI, not being a combi doesn't automatically make it a 'system' boiler -
'conventional' may be a better word.

So there's a vent pipe connected *after* the pump, which loops over the top
of the F&E tank. There must also be a feed pipe running from the bottom of
the F&E tank. Where does that connect into the boiler flow pipework?

You have pretty certainly got a case of pump-over - where water is being
pumped up the vent pipe into the F&E tank - to be replaced by water flowing
down the fill pipe, and back into the system. This is *bad*. Not only is it
wasting heat, it is also introducing trapped air into the system - which
will cause corrosion.

If your pump has several speeds, you could try slowing it down a bit - to
see whether that cures the pump-over whilst still heating the radiators
adequately. Otherwise, some plumbing mods will be needed. The fill and vent
pipe connections into the main flow pipe should both be on the boiler side
of the pump rather than after the pump, and they should be no more than 100
mm apart - so that they both experience essentially the same dynamic
pressure - making it impossible for water to circulate between them.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

I have mis informed u all. The overflow to the header IS before the pump i.e
on the suction side of the pump.
The pump has a red dial on the electrical box numbered 1 to 3. I take it
this is the speed. It is set to 2 at the moment. Would it be o.k to lower to
1 until i get the plumber back in on monday.

cheers
"Set Square" wrote in message
...
In an earlier contribution to this discussion,
dbroms wrote:

my system has just been converted by installing a diverter valve to
hopefully allow me to select heating OR ho****er.
I have had fitted a worcester bosch condensing (non combi hence
system) boiler. The pump has a tee piece straight after it, one pipe
goes to an open pipe just above the water line in a header tank in
the loft and the other goes to AB connection on the 3 way valve.
It is definately vented , no fill loop or pressure vessels.

do u require anymore info?

AIUI, not being a combi doesn't automatically make it a 'system' boiler -
'conventional' may be a better word.

So there's a vent pipe connected *after* the pump, which loops over the
top
of the F&E tank. There must also be a feed pipe running from the bottom of
the F&E tank. Where does that connect into the boiler flow pipework?

You have pretty certainly got a case of pump-over - where water is being
pumped up the vent pipe into the F&E tank - to be replaced by water
flowing
down the fill pipe, and back into the system. This is *bad*. Not only is
it
wasting heat, it is also introducing trapped air into the system - which
will cause corrosion.

If your pump has several speeds, you could try slowing it down a bit - to
see whether that cures the pump-over whilst still heating the radiators
adequately. Otherwise, some plumbing mods will be needed. The fill and
vent
pipe connections into the main flow pipe should both be on the boiler side
of the pump rather than after the pump, and they should be no more than
100
mm apart - so that they both experience essentially the same dynamic
pressure - making it impossible for water to circulate between them.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

In an earlier contribution to this discussion,
dbroms wrote:

I have mis informed u all. The overflow to the header IS before the
pump i.e on the suction side of the pump.
The pump has a red dial on the electrical box numbered 1 to 3. I take
it this is the speed. It is set to 2 at the moment. Would it be o.k
to lower to 1 until i get the plumber back in on monday.


Yes - provided the radiators still get hot.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

dbroms wrote:

We have just had a new worcester bosch system boiler fitted to a fully
pumped system. In the night we heard lots of noise from all the pipework and
the radiators so i went in the loft today to check something and found the
header tank which tops up the system has quite hot water in it !!

is this normal? i suspect not

It can be quite normal. The header tank is in fact a feed and expansion
tank. So not only does it feed water into the system when required, it
also exists to allow the water in the system somewhere to expand as it
heats up. Hence when operating you would expect the content of the tank
to be at least worm.

what could this be caused by?

see above, and also in your case "pumping over".

Does you pump have a speed selection switch on it? If so what speed is
it running at? If not already the slowest speed have you tried lowering it?


--
Cheers,

John.

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In an earlier contribution to this discussion,
John Rumm wrote:

Hence when operating you would expect the
content of the tank to be at least worm.


I hope there are not too many worms in his tank! They'd probably be killed
by the *warm* water, anyway! g
--
Cheers,
Set Square
______
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Hi all

just an update, the corgi registered installers came back around today and
fitted an automatic bypass, the problem seems to be the same but now the
boilers main indicator light flashes on/off as the boiler shuts down. In the
manual it says its due to overheating which i suppose is the hot water
coming straight back from the pump via the bypass. The problems only seem to
happen at night.........which inturn wakes everyone up with the noise of the
water pumping over.
I am using the honeywell cm-zone trvs and controller if anyone has any
experience of setting these up i could do with some advice !

cheers

Daz
"Set Square" wrote in message
...
In an earlier contribution to this discussion,
John Rumm wrote:

Hence when operating you would expect the
content of the tank to be at least worm.


I hope there are not too many worms in his tank! They'd probably be killed
by the *warm* water, anyway! g
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.