Hello,

I have a gravity hot water / pumped central heating system. I drained
the system to replace a radiator, and on refilling have the following
results:

Hot water is not heating. Boiler turns on, but cycles off after about
30 second.
Radiators are not filling up with water, despite tying to bleed them.

I have checked the header tank, and it is full. The layout of the
heating is that the boiler and hot water cyllender are on the first
floor, with all the central heating pipes in the ceiling of the ground
floor (with pipes going down to each radiator on the ground floor).

Any ideas?

Thanks for any info,

Tony Lennard

wrote in message
oups.com...
Hello,

I have a gravity hot water / pumped central heating system. I drained
the system to replace a radiator, and on refilling have the following
results:

Hot water is not heating. Boiler turns on, but cycles off after about
30 second.
Radiators are not filling up with water, despite tying to bleed them.

I have checked the header tank, and it is full. The layout of the
heating is that the boiler and hot water cyllender are on the first
floor, with all the central heating pipes in the ceiling of the ground
floor (with pipes going down to each radiator on the ground floor).

Any ideas?

Probably airlocked - connect hose pipe to drain cock and gently introduce
water untill it comes out of the header tank overflow, then try bleeding
rads as normal, finally don't forget to add inhibitor to the system

Regards Jeff

In an earlier contribution to this discussion,
Jeff wrote:

wrote in message
oups.com...
Hello,

I have a gravity hot water / pumped central heating system. I drained
the system to replace a radiator, and on refilling have the following
results:

Hot water is not heating. Boiler turns on, but cycles off after about
30 second.
Radiators are not filling up with water, despite tying to bleed them.

I have checked the header tank, and it is full. The layout of the
heating is that the boiler and hot water cyllender are on the first
floor, with all the central heating pipes in the ceiling of the
ground floor (with pipes going down to each radiator on the ground
floor).

Any ideas?

Probably airlocked - connect hose pipe to drain cock and gently
introduce water untill it comes out of the header tank overflow, then
try bleeding rads as normal, finally don't forget to add inhibitor to
the system

Regards Jeff

I agree with that. Another thought - is there a tap or gate valve in the
feed from the fill and expansion tank to the system? If so, is it open?

Yet another thought - you *are* looking at the right header tank, aren't
you? The important one here is the small fill & expansion tank which feeds
the primary circuit - *not* the larger header tank which feeds the hot DHW
cylinder. Make sure that there is water in the small tank - and that it's
ball valve isn't stuck shut.

--
Cheers,
Set Square
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Please reply to newsgroup. Reply address is invalid.

I have a gravity hot water / pumped central heating system. I drained
the system to replace a radiator, and on refilling have the following
results:

These are the kind of problems that made me convert to a fully-pumped,
sealed system last year.
It was quite easy after a bit of planning. The hot water heating is much
improved and I never have air in the system (since I fitted an air
separator).
The FAQ covers most of what you need to know.

Rgds
Alec

On Wed, 08 Jun 2005 15:31:29 -0700, tonylennard2000 wrote:

Hello,

I have a gravity hot water / pumped central heating system. I drained
the system to replace a radiator, and on refilling have the following
results:

Hot water is not heating. Boiler turns on, but cycles off after about
30 second.
Radiators are not filling up with water, despite tying to bleed them.

I have checked the header tank, and it is full. The layout of the
heating is that the boiler and hot water cyllender are on the first
floor, with all the central heating pipes in the ceiling of the ground
floor (with pipes going down to each radiator on the ground floor).

Any ideas?

Thanks for any info,


I would strongly suspect a limescale plug at or near where the feed pipe
enter the main circuit.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

Thanks for the promt reply - it worked a treat!

Thanks

Tony Lennard

In an earlier contribution to this discussion,
wrote:

Thanks for the promt reply - it worked a treat!

Thanks

Tony Lennard

It would be helpful if you you quoted part of the message to which you are
replying - so that we can see *which* solution worked.
--
Cheers,
Set Square
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