I have recently noticed my expansion tank overflow is dripping, it
only seems to have started during this protracted cold spell. I have
inspected the tank and it is not the ball cock the excess water is
coming from the expansion pipe. I have drained some water from the
system to reduce the water level, vented all the radiators but found
no air in the system, I have also set the pump on a lower setting. Is
this something I should be concerned about or is it the system doing
what it should be doing. If it requires attention what needs doing?

Thanks Richard

On Dec 23, 1:58*pm, Tricky Dicky wrote:
I have recently noticed my expansion tank overflow is dripping, it
only seems to have started during this protracted cold spell. I have
inspected the tank and it is not the ball cock the excess water is
coming from the expansion pipe. I have drained some water from the
system to reduce the water level, vented all the radiators but found
no air in the system, I have also set the pump on a lower setting. Is
this something I should be concerned about or is it the system doing
what it should be doing. If it requires attention what needs doing?

Thanks Richard

Well not normal. You need to keep an eye on it. If it persists you
will have to take some action.
One possibility is a leaky heat exchanger in the hot water cylinder.
Or even faulty mixer tap. Frozen pipe somewhere. Quite unusual these
though.

On 23/12/2010 13:58, Tricky Dicky wrote:
I have recently noticed my expansion tank overflow is dripping, it
only seems to have started during this protracted cold spell. I have
inspected the tank and it is not the ball cock the excess water is
coming from the expansion pipe. I have drained some water from the
system to reduce the water level, vented all the radiators but found
no air in the system, I have also set the pump on a lower setting. Is
this something I should be concerned about or is it the system doing
what it should be doing. If it requires attention what needs doing?

Thanks Richard

Does the level continue to rise when you drain some out and tie up the
ball valve to stop any fresh mains water from coming in?

Do you have a header tank for the hot water system, whose level is
higher than that in the F&E tank?

If the answer to both of these questions is 'yes', the prime suspect -
as someone else has suggested - has to be a hole in the indirect coil
inside the HW cylinder. The pressure in the cylinder - surrounding the
coil - will be slightly higher than that inside the coil due to the
difference in levels of the water in the respective header tanks. Thus,
if there is a leak in the coil, water will flow *into* the coil, and
thus into the primary circuit, causing the water level in the F&E tank
to rise.
--
Cheers,
Roger
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checked.

"Roger Mills" wrote in message
...
On 23/12/2010 13:58, Tricky Dicky wrote:
I have recently noticed my expansion tank overflow is dripping, it
only seems to have started during this protracted cold spell. I have
inspected the tank and it is not the ball cock the excess water is
coming from the expansion pipe. I have drained some water from the
system to reduce the water level, vented all the radiators but found
no air in the system, I have also set the pump on a lower setting. Is
this something I should be concerned about or is it the system doing
what it should be doing. If it requires attention what needs doing?

Thanks Richard

Does the level continue to rise when you drain some out and tie up the
ball valve to stop any fresh mains water from coming in?

Do you have a header tank for the hot water system, whose level is higher
than that in the F&E tank?

If the answer to both of these questions is 'yes', the prime suspect - as
someone else has suggested - has to be a hole in the indirect coil inside
the HW cylinder. The pressure in the cylinder - surrounding the coil -
will be slightly higher than that inside the coil due to the difference in
levels of the water in the respective header tanks. Thus, if there is a
leak in the coil, water will flow *into* the coil, and thus into the
primary circuit, causing the water level in the F&E tank to rise.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.



Can it be:

When the water cools it contracts and lowers the level in the header tank.
This admits more water - then when it heats up it expands and pushes the
surplus out of the overflow. I think this line is worth thinking about
before looking for leaks in the heat exchanger.
If the header tank is a relatively small surface area then a bit of
expansion can make quite a difference to the level.

Does it mainly leak when starting up the heating and then doesn't leak until
next time? The header tank acts as an expansion space.

On 23/12/2010 19:35, John wrote:
"Roger wrote in message
...
On 23/12/2010 13:58, Tricky Dicky wrote:
I have recently noticed my expansion tank overflow is dripping, it
only seems to have started during this protracted cold spell. I have
inspected the tank and it is not the ball cock the excess water is
coming from the expansion pipe. I have drained some water from the
system to reduce the water level, vented all the radiators but found
no air in the system, I have also set the pump on a lower setting. Is
this something I should be concerned about or is it the system doing
what it should be doing. If it requires attention what needs doing?

Thanks Richard

Does the level continue to rise when you drain some out and tie up the
ball valve to stop any fresh mains water from coming in?

Do you have a header tank for the hot water system, whose level is higher
than that in the F&E tank?

If the answer to both of these questions is 'yes', the prime suspect - as
someone else has suggested - has to be a hole in the indirect coil inside
the HW cylinder. The pressure in the cylinder - surrounding the coil -
will be slightly higher than that inside the coil due to the difference in
levels of the water in the respective header tanks. Thus, if there is a
leak in the coil, water will flow *into* the coil, and thus into the
primary circuit, causing the water level in the F&E tank to rise.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.



Can it be:

When the water cools it contracts and lowers the level in the header tank.
This admits more water - then when it heats up it expands and pushes the
surplus out of the overflow.

That *can* happen if the water level is set too high to start with.

But if, with the static level lowered and the ball valve disabled, the
level *still* rises (other than by the natural effects of expansion)
there *must* be some 'foreign' water getting into the primary ciruit.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On Dec 23, 8:28*pm, Roger Mills wrote:
On 23/12/2010 19:35, John wrote:





"Roger *wrote in message
...
On 23/12/2010 13:58, Tricky Dicky wrote:
I have recently noticed my expansion tank overflow is dripping, it
only seems to have started during this protracted cold spell. I have
inspected the tank and it is not the ball cock the excess water is
coming from the expansion pipe. I have drained some water from the
system to reduce the water level, vented all the radiators but found
no air in the system, I have also set the pump on a lower setting. Is
this something I should be concerned about or is it the system doing
what it should be doing. If it requires attention what needs doing?

Thanks Richard

Does the level continue to rise when you drain some out and tie up the
ball valve to stop any fresh mains water from coming in?

Do you have a header tank for the hot water system, whose level is higher
than that in the F&E tank?

If the answer to both of these questions is 'yes', the prime suspect - as
someone else has suggested - has to be a hole in the indirect coil inside
the HW cylinder. The pressure in the cylinder - surrounding the coil -
will be slightly higher than that inside the coil due to the difference in
levels of the water in the respective header tanks. Thus, if there is a
leak in the coil, water will flow *into* the coil, and thus into the
primary circuit, causing the water level in the F&E tank to rise.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

Can it be:

When the water cools it contracts and lowers the level in the header tank.
This admits more water - then when it heats up it expands and pushes the
surplus out of the overflow.

That *can* happen if the water level is set too high to start with.

But if, with the static level lowered and the ball valve disabled, the
level *still* rises (other than by the natural effects of expansion)
there *must* be some 'foreign' water getting into the primary ciruit.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.- Hide quoted text -

- Show quoted text -

Thanks all I will be trying to make sure it is not the ball cock
today. I will report back later.

Richard

On Dec 24, 8:39*am, Tricky Dicky wrote:
On Dec 23, 8:28*pm, Roger Mills wrote:





On 23/12/2010 19:35, John wrote:

"Roger *wrote in message
...
On 23/12/2010 13:58, Tricky Dicky wrote:
I have recently noticed my expansion tank overflow is dripping, it
only seems to have started during this protracted cold spell. I have
inspected the tank and it is not the ball cock the excess water is
coming from the expansion pipe. I have drained some water from the
system to reduce the water level, vented all the radiators but found
no air in the system, I have also set the pump on a lower setting. Is
this something I should be concerned about or is it the system doing
what it should be doing. If it requires attention what needs doing?

Thanks Richard

Does the level continue to rise when you drain some out and tie up the
ball valve to stop any fresh mains water from coming in?

Do you have a header tank for the hot water system, whose level is higher
than that in the F&E tank?

If the answer to both of these questions is 'yes', the prime suspect - as
someone else has suggested - has to be a hole in the indirect coil inside
the HW cylinder. The pressure in the cylinder - surrounding the coil -
will be slightly higher than that inside the coil due to the difference in
levels of the water in the respective header tanks. Thus, if there is a
leak in the coil, water will flow *into* the coil, and thus into the
primary circuit, causing the water level in the F&E tank to rise.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

Can it be:

When the water cools it contracts and lowers the level in the header tank.
This admits more water - then when it heats up it expands and pushes the
surplus out of the overflow.

That *can* happen if the water level is set too high to start with.

But if, with the static level lowered and the ball valve disabled, the
level *still* rises (other than by the natural effects of expansion)
there *must* be some 'foreign' water getting into the primary ciruit.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.- Hide quoted text -

- Show quoted text -

Thanks all I will be trying to make sure it is not the ball cock
today. I will report back later.

Richard- Hide quoted text -

- Show quoted text -

Back again

I have checked the ball cock on the F&E tank, the washer was slightly
worn changed it but still got an ever so slight drip. I changed it
with a new one ( belt & braces) no drips from the ball cock but all
the time I was working on the ball cock the heating was on and water
continued to drip out of the expansion pipe. Conclusion - it must be
the heat exchanger in the hot water cistern. Only good thing is at
least this is an item covered under EONs central heating care so it
should be a free repair/replacement.

Thanks for all the help
Richard