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ARW ARW is offline
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Default Filling up gravity central heating

The water to the header tank was turned off and the system drained down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still full
when I went to turn the water on.


Suggestions?

--

Adam
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Default Filling up gravity central heating

On 06/10/2019 13:00, ARW wrote:
The water to the header tank was turned off and the system drained down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still full
when I went to turn the water on.


Suggestions?

--

Adam


Airlock.

No CH when I was a kid, but a routine at home every time a hot water tap
washer had to be changed was to connect a hose between hot and cold
water taps in the bathroom, and turn both on.
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In message ,
newshound writes
On 06/10/2019 13:00, ARW wrote:
The water to the header tank was turned off and the system drained down.
Swapped the mid position vale and it will now not fill back up.
The odd thing is the header tank did not drain off - it was still
full when I went to turn the water on.
Suggestions?
-- Adam


Airlock.

No CH when I was a kid, but a routine at home every time a hot water
tap washer had to be changed was to connect a hose between hot and cold
water taps in the bathroom, and turn both on.


I don't suppose that was a cottage in Southwold?:-)

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Tim Lamb
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Default Filling up gravity central heating

On 06/10/2019 13:00, ARW wrote:
The water to the header tank was turned off and the system drained down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still full
when I went to turn the water on.


Suggestions?

--

Adam


Congealed sludge in the downfeed from the header? I had that a few years
ago on a bend situated behind the hot water tank. Happy days.
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On 06/10/2019 15:06, newshound wrote:
On 06/10/2019 13:00, ARW wrote:
The water to the header tank was turned off and the system drained down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still full
when I went to turn the water on.


Suggestions?

--

Adam


Airlock.

No CH when I was a kid, but a routine at home every time a hot water tap
washer had to be changed was to connect a hose between hot and cold
water taps in the bathroom, and turn both on.


+1,

except that both those taps would be fed from the same tank so
should have equal pressure.

Connecting the kitchen cold tap fed from incoming mains to
a hot tap would be more like it.


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Default Filling up gravity central heating

On 06/10/2019 15:44, Andy Bennet wrote:
On 06/10/2019 13:00, ARW wrote:
The water to the header tank was turned off and the system drained down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still full
when I went to turn the water on.


Suggestions?

--

Adam


Congealed sludge in the downfeed from the header? I had that a few years
ago on a bend situated behind the hot water tank. Happy days.


especially since the blockage might have suddenly released when the
valve was removed :-)
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Andrew wrote:

except that both those taps would be fed from the same tank so
should have equal pressure.


varies (by region?) ... no cold tap in this house is fed from the tank
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On 06/10/2019 16:12, Andrew wrote:
On 06/10/2019 15:06, newshound wrote:
On 06/10/2019 13:00, ARW wrote:
The water to the header tank was turned off and the system drained down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still
full when I went to turn the water on.


Suggestions?

--

Adam


Airlock.

No CH when I was a kid, but a routine at home every time a hot water
tap washer had to be changed was to connect a hose between hot and
cold water taps in the bathroom, and turn both on.


+1,

except that both those taps would be fed from the same tank so
should have equal pressure.

Connecting the kitchen cold tap fed from incoming mains to
a hot tap would be more like it.


The HW tank is not relevant is it?

I never touched it.






--
Adam
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We used to get airlocks in the DHW system whenever it was drained down (too many pipes horizontal ). Remedy was to connect the hot and cold feeds for the washing machine and let mains pressure water back fill the pipes as soon as a rumble of air bubbles could be heard in the main cold water tank or water came out of the overflow pipe then it was turned off and system worked perfectly.

I suppose you could do something similar with a hose connected to one of the drain off cocks but you would need to secure it tight on the drain off cock or it could be water, water everywhere. The other thing to watch is the header tank as on CH systems they are quite small and soon fill the overflow should deal with it but better not to take chances.

As for why your header may be full of water it depends where the turn off valve is. If in the supply pipe to the ball cock then the tank will empty. If on the downfeed pipe header to CH system then water will be retained in the header.

Richard
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On Sun, 06 Oct 2019 16:12:03 +0100, Andrew wrote:

On 06/10/2019 15:06, newshound wrote:
On 06/10/2019 13:00, ARW wrote:
The water to the header tank was turned off and the system drained
down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still full
when I went to turn the water on.


Suggestions?

--

Adam


Airlock.

No CH when I was a kid, but a routine at home every time a hot water
tap washer had to be changed was to connect a hose between hot and cold
water taps in the bathroom, and turn both on.


+1,

except that both those taps would be fed from the same tank so should
have equal pressure.

Connecting the kitchen cold tap fed from incoming mains to a hot tap
would be more like it.


Doesn't work with the header tank, though.



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Default Filling up gravity central heating

On 06/10/2019 16:19, ARW wrote:
On 06/10/2019 16:12, Andrew wrote:
On 06/10/2019 15:06, newshound wrote:
On 06/10/2019 13:00, ARW wrote:
The water to the header tank was turned off and the system drained
down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still
full when I went to turn the water on.


Suggestions?

--

Adam

Airlock.

No CH when I was a kid, but a routine at home every time a hot water
tap washer had to be changed was to connect a hose between hot and
cold water taps in the bathroom, and turn both on.


+1,

except that both those taps would be fed from the same tank so
should have equal pressure.

Connecting the kitchen cold tap fed from incoming mains to
a hot tap would be more like it.


The HW tank is not relevant is it?

I never touched it.






In that case try connecting a hosepipe to the C/H drain cock,
and see if that pushes water up into the C/H header tank ?.

You might have to manually move the 3W valve to the heating
position.
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On 06/10/2019 17:09, Andrew wrote:

You might have to manually move the 3W valve to the heating
position.


There is usually (always?) a manual lever on the valve which allows both
sides to be open and latched to facilitate filling. The latch on the
manual lever should be overriden when the system is in operation by
first switching to CH and then hot water only.

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Default Filling up gravity central heating

Gunged up T-Junction, where the feed pipe from the header tank joins the main heating pipework.

Mike
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On Sunday, 6 October 2019 16:13:30 UTC+1, Andrew wrote:
especially since the blockage might have suddenly released when the
valve was removed :-)


Mine did, as we were moving a full HW cylinder ;-)

Owain

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On 06/10/2019 13:00, ARW wrote:
The water to the header tank was turned off and the system drained down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still full
when I went to turn the water on.


Suggestions?

--

Adam



Hi Adam,

I'm confused! Which bit is gravity? If there's a mid-position valve, the
primary circuit is presumably fully pumped. It may be vented (as opposed
to pressurised) if there's a small fill and expansion tank - but that
doesn't make it "gravity". Is it thins tank which you're referring to as
the header tank, or do you mean the large cold water header for the
(presumably) gravity HW system?

Can you clarify just what you mean by "won't fill back up". Exactly what
is happening or not happening?

As someone else has pointed out, the 3-way valve will be in the HW-only
position when no power is applies to it. The manual lever moves it to
the mid position, when you should get some flow to both circuits. You
may need to do that if the primary circuit won't refill properly.
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Default Filling up gravity central heating

On 06/10/2019 13:00, ARW wrote:
The water to the header tank was turned off and the system drained down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still full
when I went to turn the water on.


Suggestions?

--

Adam


If there is a pump, make sure that there is water in it by opening the
bleed screw and then apply power.

Also bleed radiators.


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Michael Chare
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Default Filling up gravity central heating

On 06/10/2019 15:06, newshound wrote:
On 06/10/2019 13:00, ARW wrote:
The water to the header tank was turned off and the system drained down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still full
when I went to turn the water on.


Suggestions?

--

Adam


Airlock.

No CH when I was a kid, but a routine at home every time a hot water tap
washer had to be changed was to connect a hose between hot and cold
water taps in the bathroom, and turn both on.



Indeed a well tested solution, but worth mentioning that will clear an
airlock in a vented hot water system, it won't help when there is one in
the vented CH primary. You would need to find a way to connect your cold
water tap to a rad tail or similar to have the same effect there.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/
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Default Filling up gravity central heating

On 06/10/2019 13:00, ARW wrote:

The water to the header tank was turned off and the system drained down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still full
when I went to turn the water on.


Suggestions?


Some crap getting sucked into the feed/expansion pipe connecting to the
CH header would be one possibility.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/
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On 06/10/2019 21:17, John Rumm wrote:
On 06/10/2019 13:00, ARW wrote:

The water to the header tank was turned off and the system drained down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still full
when I went to turn the water on.


Suggestions?


Some crap getting sucked into the feed/expansion pipe connecting to the
CH header would be one possibility.


Should have added, that a wet'n'dry vac hose held under water and over
the outlet of the CH tank, might be worth a shot to see if you can suck
some water back. Failing that, a hose stuffed down it, might fors some
water though.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/


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On 06/10/2019 19:40, Michael Chare wrote:
On 06/10/2019 13:00, ARW wrote:
The water to the header tank was turned off and the system drained down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still full
when I went to turn the water on.


Suggestions?

--

Adam


If there is a pump, make sure that there is water in it by opening the
bleed screw and then apply power.

Also bleed radiators.




There may also be a bleed in the high point of the hot water system.
Mine had an auto bleed valve but the screw on cover was tightly on thus
only allowing a limited amount of air to escape until the cover was
unscrewed.

--
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On 06/10/2019 15:44, Andy Bennet wrote:
On 06/10/2019 13:00, ARW wrote:
The water to the header tank was turned off and the system drained down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still full
when I went to turn the water on.


Suggestions?

--

Adam


Congealed sludge in the downfeed from the header? I had that a few years
ago on a bend situated behind the hot water tank. Happy days.


Correct and a 15mm gate valve that I did not know (shelves full of
towels etc) between the header tank to the CH pipework (joining into the
CH pipework just below the air separator) that I did know about.

It looks like the valve was not fully open (and has probably been like
that for 20 years) allowing crud and to fill the 15mm feeder pipe.

New gate valve and a bucket of water through the header tank and all is
well.

Thank you to you and everyone else that has helped.

--
Adam
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On 07/10/2019 18:43, ARW wrote:
On 06/10/2019 15:44, Andy Bennet wrote:
On 06/10/2019 13:00, ARW wrote:
The water to the header tank was turned off and the system drained down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still
full when I went to turn the water on.


Suggestions?

--

Adam


Congealed sludge in the downfeed from the header? I had that a few
years ago on a bend situated behind the hot water tank. Happy days.


Correct and a 15mm gate valve that I did not know (shelves full of
towels etc) between the header tank to the CH pipework (joining into the
CH pipework just below the air separator) that I did know about.

It looks like the valve was not fully open (and has probably been like
that for 20 years) allowing crud and to fill the 15mm feeder pipe.

New gate valve and a bucket of water through the header tank and all is
well.

Thank you to you and everyone else that has helped.


Don't forget the inhibitor :-)
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Default Filling up gravity central heating

On 06/10/2019 17:09, Andrew wrote:
On 06/10/2019 16:19, ARW wrote:
On 06/10/2019 16:12, Andrew wrote:
On 06/10/2019 15:06, newshound wrote:
On 06/10/2019 13:00, ARW wrote:
The water to the header tank was turned off and the system drained
down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still
full when I went to turn the water on.


Suggestions?

--

Adam

Airlock.

No CH when I was a kid, but a routine at home every time a hot water
tap washer had to be changed was to connect a hose between hot and
cold water taps in the bathroom, and turn both on.

+1,

except that both those taps would be fed from the same tank so
should have equal pressure.

Connecting the kitchen cold tap fed from incoming mains to
a hot tap would be more like it.


The HW tank is not relevant is it?

I never touched it.






In that case try connecting a hosepipe to the C/H drain cock,
and see if that pushes water up into the C/H header tank ?.

You might have to manually move the 3W valve to the heating
position.


I did. We filled the CH circuit up that way and eventually it started
adding more water to the already full CH header tank via the expansion pipe.

I now realise the logical conclusion at this point would have been to
block the expansion pipe and try to fill the header tank via it's feed
pipe (ie the 15mm gravity feed pipe that the tank uses to feed the CH
pipework from) or in other words (Star Trek and Scotty anyone, just
reverse the gravity laddie) to prove that this pipe was blocked.

Cheers for the help. Much appreciated.


--
Adam
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On 07/10/2019 18:46, Andrew wrote:
On 07/10/2019 18:43, ARW wrote:
On 06/10/2019 15:44, Andy Bennet wrote:
On 06/10/2019 13:00, ARW wrote:
The water to the header tank was turned off and the system drained
down.

Swapped the mid position vale and it will now not fill back up.

The odd thing is the header tank did not drain off - it was still
full when I went to turn the water on.


Suggestions?

--

Adam

Congealed sludge in the downfeed from the header? I had that a few
years ago on a bend situated behind the hot water tank. Happy days.


Correct and a 15mm gate valve that I did not know (shelves full of
towels etc) between the header tank to the CH pipework (joining into
the CH pipework just below the air separator) that I did know about.

It looks like the valve was not fully open (and has probably been like
that for 20 years) allowing crud and to fill the 15mm feeder pipe.

New gate valve and a bucket of water through the header tank and all
is well.

Thank you to you and everyone else that has helped.


Don't forget the inhibitor :-)



I certainly did not. I have **** loads of the stuff as some new-builds I
was working on had electric only heating. The bathroom and en suite had
water filled towel rads with electric elements and they sent a full
bottle of inhibitor with every house. One bottle did all 20 houses and I
kept the rest:-)

--
Adam
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