There is something rather unwell with my heating system but it's never been
quite right since I bought this house. Current problem is the radiator
nearest the boiler and pump (which is upstairs in the back bedroom) is
continually filling with air. Bleed it and it goes hot instantly but will be
full of air in a couple of days. Air and bubbling can also be heard in and
around the boiler/pump. Additionally, there is a little overflow pipe
sticking out of the wall just above the boiler that is continually dripping.
I'm not sure how long it's been dripping for. It drips whether the central
heating is on or off.

Now some history:

The pump packed up a couple of years ago and the plumber who fixed it said
that whoever had installed the central heating got some pipe work wrong
around the pump area which meant it would be pulling air into the system.
Even if it was, does it explain why suddenly more air is getting in.

I recently drained the system twice in order to remove and decorate behind a
radiator in the bedroom. This radiator is working fine. However, some quirks
he firstly, the water only dribbled out of the release valve in the
cellar (the lowest point). Secondly, upon refilling it took an awfully long
time for the radiators to start getting hot again. The thermostat on the
boiler was set to very low - it's currently on medium. Could there be a
blockage somewhere?

There is a very slight weeping of one of the radiators downstairs - so
slight that the water evaporate before it drips. It's been sealed with
something I got from B&Q - a sort of silicon sealant stuff. Not sure how
effective it is though. Could a slight air leak like this cause a radiator
at the other end of the house to fill with air?

The radiator down in the cellar is damaged but as I don't particularly want
to heat the cellar, it's turned off at both ends.

Any ideas? I suspect I need a good plumber in here - whilst I understand the
principles of the thing, diagnosing something like this is a lot more
difficult.

Thanks, Rob.

On Sat, 12 Mar 2005 15:27:37 +0000, Rob Nicholson wrote:

There is something rather unwell with my heating system but it's never been
quite right since I bought this house. Current problem is the radiator
nearest the boiler and pump (which is upstairs in the back bedroom) is
continually filling with air. Bleed it and it goes hot instantly but will be
full of air in a couple of days. Air and bubbling can also be heard in and
around the boiler/pump. Additionally, there is a little overflow pipe
sticking out of the wall just above the boiler that is continually dripping.
I'm not sure how long it's been dripping for. It drips whether the central
heating is on or off.

Now some history:

The pump packed up a couple of years ago and the plumber who fixed it said
that whoever had installed the central heating got some pipe work wrong
around the pump area which meant it would be pulling air into the system.
Even if it was, does it explain why suddenly more air is getting in.

I recently drained the system twice in order to remove and decorate behind a
radiator in the bedroom. This radiator is working fine. However, some quirks
he firstly, the water only dribbled out of the release valve in the
cellar (the lowest point). Secondly, upon refilling it took an awfully long
time for the radiators to start getting hot again. The thermostat on the
boiler was set to very low - it's currently on medium. Could there be a
blockage somewhere?

There is a very slight weeping of one of the radiators downstairs - so
slight that the water evaporate before it drips. It's been sealed with
something I got from B&Q - a sort of silicon sealant stuff. Not sure how
effective it is though. Could a slight air leak like this cause a radiator
at the other end of the house to fill with air?

The radiator down in the cellar is damaged but as I don't particularly want
to heat the cellar, it's turned off at both ends.

Any ideas? I suspect I need a good plumber in here - whilst I understand the
principles of the thing, diagnosing something like this is a lot more
difficult.

I expect that this system is open vented and the pipe above the boiler is
the over flow for the little (10 litre) F&E cistern.

A few photos of the pump / boiler area would help a lot.

The pipework need fixing to stop the air entering and before other
problems get too serious.

The valve in the cellar is a drain point - the washers often weld
themselves in place and opening the valve only allows water out from the
middle of the washer.



--
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

In message , Rob Nicholson
wrote
There is something rather unwell with my heating system but it's never been
quite right since I bought this house. Current problem is the radiator
nearest the boiler and pump (which is upstairs in the back bedroom) is
continually filling with air. Bleed it and it goes hot instantly but will be
full of air in a couple of days. Air and bubbling can also be heard in and
around the boiler/pump. Additionally, there is a little overflow pipe
sticking out of the wall just above the boiler that is continually dripping.
I'm not sure how long it's been dripping for. It drips whether the central
heating is on or off.


One possibility is that the pump is running too fast. It probably has
three speed settings - reduce the speed. You may have to re-balance the
system.


I recently drained the system twice in order to remove and decorate behind a
radiator in the bedroom. This radiator is working fine. However, some quirks
he firstly, the water only dribbled out of the release valve in the
cellar (the lowest point). Secondly, upon refilling it took an awfully long
time for the radiators to start getting hot again. The thermostat on the
boiler was set to very low - it's currently on medium. Could there be a
blockage somewhere?

You may have an airlock in the pipes feeding that radiator. To clear try
turning off all the radiators except the problem one.

--
Alan

I expect that this system is open vented and the pipe above the boiler is
the over flow for the little (10 litre) F&E cistern.

A few photos of the pump / boiler area would help a lot.

I'll snap a dig photo later and post it. Need to move out a lot of junk from
the cupboard :-)

The pipework need fixing to stop the air entering and before other
problems get too serious.

Suspected that - will order and replace the two faulty radiators. I was
putting it off as the weeping on is a large one in the lounge, biggest in
the house :-(

The valve in the cellar is a drain point - the washers often weld
themselves in place and opening the valve only allows water out from the
middle of the washer.

Okay, won't worry about that too much then.

Cheers, Rob.

You may have an airlock in the pipes feeding that radiator. To clear try
turning off all the radiators except the problem one.

Will do - later...

"Rob Nicholson" wrote in message
...
There is something rather unwell with my heating system but it's never
been
quite right since I bought this house. Current problem is the radiator
nearest the boiler and pump (which is upstairs in the back bedroom) is
continually filling with air. Bleed it and it goes hot instantly but will
be
full of air in a couple of days. Air and bubbling can also be heard in and
around the boiler/pump.
snip
I recently drained the system twice in order to remove and decorate behind
a
radiator in the bedroom.
snip

When you drained the system, did you run it for a while with a flushing
compound then drain it again then refill with an inhibitor such as Fernox?

A long time ago I had a problem with one radiator constantly filling up with
air (or other gass(es) ) and was advised that this could be the result of
corrosion of the inside of the radiators. This gets worse when you add fresh
water - apparently the water can stabilise a little after time.

I ran with the flushing compounr, flushed the system, then added fernox and
the radiator stopped filling with air.

Another indication that all is not well is if the water coming out when you
bleed the radiator is blackish instead of clear.

Have you ever flushed/treated the system?

Could be worth a go.

HTH
Dave R

P.S. not talking about power flushing - just running with a treatment in for
a week.
There used to be regular threads about the benefits/not of power flushing.
Basically you can save a lot of money by cleaning out your system yourself
e.g. by taking individual radiators off the wall then flushing them through
with a hose pipe outside.
Having said all this, my neighbour had his system power flushed because
radiators were not heating up, and he said there was an amazing difference.