S
sturharv
Why does hydrogen sometimes come out of rads when they are bled!
Well I never knew it was hydrogen that filled up raditors to make them cold
- just thought it was air. Anyway this is apparently why:
Even where there is a positive pressure, yet no leakage of water, there may still be contact with the atmosphere, the surface tension of the water may be preventing any flow through capillaries. Under such conditions oxygen will enter the system.
In its simplest form, the reaction between iron (steel) and oxygen in the presence of water produces iron oxides (initially rust) and hydrogen gas. The effect of hydrogen production is to depress the water level in the radiators, so producing a cold area at the top. Sufficient pressure can be produced to split aluminium radiators. The gas will often end up in one radiator at the point of lowest pressure, furthest from the circulator. The gas is slightly soluble in water and, although produced elsewhere, will transfer to the point of least resistance.
- just thought it was air. Anyway this is apparently why:
Even where there is a positive pressure, yet no leakage of water, there may still be contact with the atmosphere, the surface tension of the water may be preventing any flow through capillaries. Under such conditions oxygen will enter the system.
In its simplest form, the reaction between iron (steel) and oxygen in the presence of water produces iron oxides (initially rust) and hydrogen gas. The effect of hydrogen production is to depress the water level in the radiators, so producing a cold area at the top. Sufficient pressure can be produced to split aluminium radiators. The gas will often end up in one radiator at the point of lowest pressure, furthest from the circulator. The gas is slightly soluble in water and, although produced elsewhere, will transfer to the point of least resistance.
S
sturharv
Great reply.
What is the easiest way to stop the problem? I know you can buy inhibitor and stuff to stop bacterial growth (or maybe replace some rads)?
What is the easiest way to stop the problem? I know you can buy inhibitor and stuff to stop bacterial growth (or maybe replace some rads)?
think sostuharve said:
andy2000 said:
Time is it kev?
hydrogen is produced from your radiator rusting inside. It isn't always hydrogen in rads, sometimes it is air that has been drawn in. Flame tests are not advisable but good fun!
Air normally sits on top of water, i guess that why we have always had bleed valves at the top, I dont think it is ever going to be circulated around the system untill it reaches a 'point of least resistance'
Air normally sits on top of water, i guess that why we have always had bleed valves at the top, I dont think it is ever going to be circulated around the system untill it reaches a 'point of least resistance'
E
expertgasman
[/quote]Don't know his DOB, but he IS nearly 3 years older than when he posted!
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