The expansion tank on my sealed system combi has failed (water comes out of the air Schrader valve when pressed). Also the pressure changes massively depending on temperature; classic symptoms.

So I have the choice of having an engineer change the boiler expansion tank, behind boiler so he'd probably have to remove boiler from manifold to get to it. £££+

Or I could fit another remote expansion tank at a much easier location (probably under floor boards).

Question is would it be okay to leave the u/s exp. tank connected to the system as its now full of water? Are there any side effects of fitting another exp. tank and keeping the old one connected?

Its a Worcester 24i Junior non-condensing boiler.

Thanks

On Friday, 18 November 2016 16:03:04 UTC, simon mitchelmore wrote:
The expansion tank on my sealed system combi has failed (water comes out of the air Schrader valve when pressed). Also the pressure changes massively depending on temperature; classic symptoms.

So I have the choice of having an engineer change the boiler expansion tank, behind boiler so he'd probably have to remove boiler from manifold to get to it. £££+

Or I could fit another remote expansion tank at a much easier location (probably under floor boards).

Question is would it be okay to leave the u/s exp. tank connected to the system as its now full of water? Are there any side effects of fitting another exp. tank and keeping the old one connected?

Its a Worcester 24i Junior non-condensing boiler.

Thanks

The existing one can be removed or abandoned and a new one fitted at a more convenient place.

It is theoretically better to remove the old one but people sometimes don't bother.

You will need access to the new one to put air in at some point in the future.

On 11/18/2016 5:17 PM, harry wrote:
On Friday, 18 November 2016 16:03:04 UTC, simon mitchelmore wrote:
The expansion tank on my sealed system combi has failed (water comes out of the air Schrader valve when pressed). Also the pressure changes massively depending on temperature; classic symptoms.

So I have the choice of having an engineer change the boiler expansion tank, behind boiler so he'd probably have to remove boiler from manifold to get to it. £££+

Or I could fit another remote expansion tank at a much easier location (probably under floor boards).

Question is would it be okay to leave the u/s exp. tank connected to the system as its now full of water? Are there any side effects of fitting another exp. tank and keeping the old one connected?

Its a Worcester 24i Junior non-condensing boiler.

Thanks

The existing one can be removed or abandoned and a new one fitted at a more convenient place.

It is theoretically better to remove the old one but people sometimes don't bother.

You will need access to the new one to put air in at some point in the future.


Don't know about that model, but replacement of the vessel was a real
PITA on one of my previous combis (didn't even have decent access for
testing).

I can't see *any* downside in leaving the old one in place and full of
water, except perhaps that in the long term it could corrode through
from the inside?

I've positioned my replacement underneath the boiler, in the relatively
dead space just in front of all the main pipework. I fitted mine on a
flexible hose so that it can be moved out of the way if required for
access to stuff. I think it is worth having a service valve in the feed,
and a drain valve, so that they can easily be isolated and drained for
repressurisation without depressurising the rest of the system, as long
as you remember to open it afterwards!

In article ,
newshound writes:
On 11/18/2016 5:17 PM, harry wrote:
On Friday, 18 November 2016 16:03:04 UTC, simon mitchelmore wrote:
The expansion tank on my sealed system combi has failed (water comes out of the air Schrader valve when pressed). Also the pressure changes massively depending on temperature; classic symptoms.

So I have the choice of having an engineer change the boiler expansion tank, behind boiler so he'd probably have to remove boiler from manifold to get to it. £££+

Or I could fit another remote expansion tank at a much easier location (probably under floor boards).

Question is would it be okay to leave the u/s exp. tank connected to the system as its now full of water? Are there any side effects of fitting another exp. tank and keeping the old one connected?

Its a Worcester 24i Junior non-condensing boiler.

Thanks

The existing one can be removed or abandoned and a new one fitted at a more convenient place.

It is theoretically better to remove the old one but people sometimes don't bother.

You will need access to the new one to put air in at some point in the future.


Don't know about that model, but replacement of the vessel was a real
PITA on one of my previous combis (didn't even have decent access for
testing).

I can't see *any* downside in leaving the old one in place and full of
water, except perhaps that in the long term it could corrode through
from the inside?

I've positioned my replacement underneath the boiler, in the relatively
dead space just in front of all the main pipework. I fitted mine on a
flexible hose so that it can be moved out of the way if required for
access to stuff. I think it is worth having a service valve in the feed,
and a drain valve, so that they can easily be isolated and drained for
repressurisation without depressurising the rest of the system, as long
as you remember to open it afterwards!

....and ideally, connect it into the system as near to the pump inlet
as you can, as the pump benefits from the pressure smoothing effect
of the pressure vessel on it's input side.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

"Andrew Gabriel" wrote in message
news
In article ,
newshound writes:
On 11/18/2016 5:17 PM, harry wrote:
On Friday, 18 November 2016 16:03:04 UTC, simon mitchelmore wrote:
The expansion tank on my sealed system combi has failed (water comes
out of the air Schrader valve when pressed). Also the pressure changes
massively depending on temperature; classic symptoms.

So I have the choice of having an engineer change the boiler expansion
tank, behind boiler so he'd probably have to remove boiler from
manifold to get to it. £££+

Or I could fit another remote expansion tank at a much easier location
(probably under floor boards).

Question is would it be okay to leave the u/s exp. tank connected to
the system as its now full of water? Are there any side effects of
fitting another exp. tank and keeping the old one connected?

Its a Worcester 24i Junior non-condensing boiler.

Thanks

The existing one can be removed or abandoned and a new one fitted at a
more convenient place.

It is theoretically better to remove the old one but people sometimes
don't bother.

You will need access to the new one to put air in at some point in the
future.


Don't know about that model, but replacement of the vessel was a real
PITA on one of my previous combis (didn't even have decent access for
testing).

I can't see *any* downside in leaving the old one in place and full of
water, except perhaps that in the long term it could corrode through
from the inside?

I've positioned my replacement underneath the boiler, in the relatively
dead space just in front of all the main pipework. I fitted mine on a
flexible hose so that it can be moved out of the way if required for
access to stuff. I think it is worth having a service valve in the feed,
and a drain valve, so that they can easily be isolated and drained for
repressurisation without depressurising the rest of the system, as long
as you remember to open it afterwards!

...and ideally, connect it into the system as near to the pump inlet
as you can, as the pump benefits from the pressure smoothing effect
of the pressure vessel on it's input side.


I've done this to another Worcester boiler (are they particularly poor
pressure vessels?) with no problems. As for internal corrosion of the old
one, I'm assuming that the inhibitor will protect, just as it does with the
rads?

Charles F