Two of my radiators have to be bled about every two weeks, the rest are
fine. I can't figure out how the air is getting into them. Any suggestions?

Martin Harran wrote:
Two of my radiators have to be bled about every two weeks, the rest
are fine. I can't figure out how the air is getting into them. Any
suggestions?

it isn't air, it's hydrogen and it's being produced because you don't
have any inhibitor in the system. drain the system, add a propretory
system cleaner, leave it in for a few weeks, drain the system and
refill after dosing the system with an inhibitor.

In article ,
"Martin Harran" writes:
Two of my radiators have to be bled about every two weeks, the rest are
fine. I can't figure out how the air is getting into them. Any suggestions?

What type of system: vented (small tank in the loft for it),
or sealed (pressure guage and filling loop, usually in or near
the boiler)?

--
Andrew Gabriel

In message , .
writes
it isn't air, it's hydrogen and it's being produced because you don't
have any inhibitor in the system.

Wow, that is marvellous. How do you manage to rule out air and deduce
all of that from the info given by the OP?

--
Bill

In an earlier contribution to this discussion,
.. wrote:

Martin Harran wrote:
Two of my radiators have to be bled about every two weeks, the rest
are fine. I can't figure out how the air is getting into them. Any
suggestions?

it isn't air, it's hydrogen and it's being produced because you don't
have any inhibitor in the system. drain the system, add a propretory
system cleaner, leave it in for a few weeks, drain the system and
refill after dosing the system with an inhibitor.

That's a very definite 'diagnosis' - based on very little information, and a
lot of assumptions!

It *may* be hydrogen - it may not. How do you *know* that there's no
inhibitor in the system?

To the OP: You need to tell us a bit more about the system - whether it's
sealed (pressurised) or vented and, if vented, whether there's any evidence
of pumping over.

Next time you have to bleed a radiator, test for hydrogen by applying a
lighted taper to the gas which comes out. It it burns with a blue flame,
it's hydrogen.
--
Cheers,
Roger
______
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monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

"Andrew Gabriel" wrote in message
...
In article ,
"Martin Harran" writes:
Two of my radiators have to be bled about every two weeks, the rest are
fine. I can't figure out how the air is getting into them. Any
suggestions?

What type of system: vented (small tank in the loft for it),
or sealed (pressure guage and filling loop, usually in or near
the boiler)?

Vented, there's no obvious signs of the system boiling over into the venting
tank - i.e. I never hear it doing so but maybe I shlod go up into the loft
and have a look when the heating is on..

Bill wrote:
In message , .
writes
it isn't air, it's hydrogen and it's being produced because you don't
have any inhibitor in the system.

Wow, that is marvellous. How do you manage to rule out air and deduce
all of that from the info given by the OP?

experience ?

"Martin Harran" wrote in message
...

"Andrew Gabriel" wrote in message
...
In article ,
"Martin Harran" writes:
Two of my radiators have to be bled about every two weeks, the rest are
fine. I can't figure out how the air is getting into them. Any
suggestions?

What type of system: vented (small tank in the loft for it),
or sealed (pressure guage and filling loop, usually in or near
the boiler)?

Vented, there's no obvious signs of the system boiling over into the
venting
tank - i.e. I never hear it doing so but maybe I shlod go up into the loft
and have a look when the heating is on..

Any boiling normally vents into your cold water tank. So if you haven't
recently flushed the toilet with warm water you probably are not
overheating. (Besides the rads would be uncommonly hot)

I once lived in a house where one upstairs rad needed total bleeding once a
week and was told that this was because (the right words will fail me here)
the air pressure valve was located too close to the pump/ or was it too
close to where the pipes split to go upstairs. Also this was a rad that
would heat by hot water or by c/h (ie bathroom rad) and no other rad ever
needed bleeding.

Peter

In an earlier contribution to this discussion,
Peter wrote:


Any boiling normally vents into your cold water tank. So if you
haven't recently flushed the toilet with warm water you probably are
not overheating.

Eh?
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

"Roger Mills" wrote in message
...
In an earlier contribution to this discussion,
. wrote:

Martin Harran wrote:
Two of my radiators have to be bled about every two weeks, the rest
are fine. I can't figure out how the air is getting into them. Any
suggestions?

it isn't air, it's hydrogen and it's being produced because you don't
have any inhibitor in the system. drain the system, add a propretory
system cleaner, leave it in for a few weeks, drain the system and
refill after dosing the system with an inhibitor.

That's a very definite 'diagnosis' - based on very little information, and
a
lot of assumptions!

It *may* be hydrogen - it may not. How do you *know* that there's no
inhibitor in the system?


Agreed, I don't have any inhibitor and I never have to bleed except when the
system is refilled where I have to bleed all season long, but after that not
at all.
Conclusion: It's air! There is an awful lot of it in fresh water. And it
takes along time of continual heat/cool to get it all out.

--
Mike W

"Roger Mills" wrote in message
...
In an earlier contribution to this discussion,
Peter wrote:


Any boiling normally vents into your cold water tank. So if you
haven't recently flushed the toilet with warm water you probably are
not overheating.

Eh?
--
Cheers,
Roger
______

exactly Eh I don't know of a system where the toilet is connected to either
tank in the loft let alone the expansion tank for the heating system

In article ,
"Mr Fixit" writes:

exactly Eh I don't know of a system where the toilet is connected to either
tank in the loft let alone the expansion tank for the heating system

Filling the toilet from the cold water storage tank is not uncommon,
although that's nothing to do with the central heating.

--
Andrew Gabriel

(Andrew Gabriel) wrote in
:


Filling the toilet from the cold water storage tank is not uncommon,
although that's nothing to do with the central heating.

It is in Peter's house

mike

"mike" wrote in message
. 1.4...
(Andrew Gabriel) wrote in
:


Filling the toilet from the cold water storage tank is not uncommon,
although that's nothing to do with the central heating.

It is in Peter's house


Haha ... ok the hot water tank expansion overflow, overflowed into the
cold water storage tank, so that when the immersion thermo failed the water
boiled into the cold tank and the toilet got a good umm cleaning.
Having said that, its somewhat divorced from the OP's problem I now realise.
(mental note... must learn to read)

Peter

mike