Need to bleed rad daily

[caw35slr]

How does air enter a pressurised system?

The towel rail in my 2nd storey loft needs bleeding daily. I'm baffled and can't figure out how air enters a system that is under pressure. There must be an answer!

FYI, boiler on ground floor. No air anywhere else.

 

[RigidRaider]

Might be hydrogen from internal oxidation. If so, you need to drain and refill the system with inhibitor.

 

[caw35slr]

How do I test that? Bleed and apply a flame?

 

[RigidRaider]

Er.... anybody tried this?

 

[greemyamochop]

Er.... anybody tried this?

All the time, if its a green flame its ok if its red add inhibitor

Simples!

 

[caw35slr]

Er.... anybody tried this?

All the time, if its a green flame its ok if its red add inhibitor

Simples!

I tried it and it produced a small flame of purest blue. Well I never! What chemical reaction is happening here? What are my next steps?

 

[misterdubya]

I'd get some inhibitor in, and pronto.

Mr. W.

 

[RigidRaider]

It's something to do with the interaction between that nasty old dihydrogen monoxide in your heating circuit with the iron in your radiators. Can't remember the schoolboy chemistry though - is it the monoxide combining with the iron to produce iron oxide and giving up the dihydrogen?

 

[Muzz]

dihydrogen monoxide is shocking, that stuff is everywhere.

It's a scandal that our environment is full of the stuff, it gets in our bodies, our food, even baby milk and the government does nothing about it despite it causing deaths every year...........

 

[MJN]

Can't remember the schoolboy chemistry though - is it the monoxide combining with the iron to produce iron oxide and giving up the dihydrogen?

Pretty much, althought the actual process is somewhat convoleted involving numerous intermediate steps, not to mention parrallel reactions in the real world. In its most simple form the reaction is:

4Fe (Iron) + 3O2 (Oxygen) ---> 2Fe2O3 (Iron Oxide i.e. rust)

Mathew

 

[caw35slr]

OK, many thanks guys. I'll get onto it.