Air vents for radiators?

[Gogs33]

Hi. Not been in this property for long but I'm looking to prolong the life of the rads. They look ok but need bleeding fairly frequently (powered by an oil fired system), this maybe because one has been removed (just the regular fittings left - which I may just put another another rad in) but anyway someone has suggested fitting an Aladdin air vent to the system. Is this a good idea or are there better options?
Cheers...Chris

 

[Newboy]

If you need to bleed the radiators frequently then there may be a number of causes, the most common being gases generated by corrosion. The system may need inhibitor adding as a first action.

 

[Gogs33]

Thanks Newboy. My problem is I've no idea how to do that with this Oil fired system. I was going to ask the service guy but he ran so quickly I couldn't ask him. I did at least find an idea number on the boiler so maybe able to get Bosch to service it now.

Cheers...Chris

 

[Burnerman]

What happens Chris is that the rust from the system (boiler internals, radiator internals etc) forms a black sludge called magnetite. This is capable of generating hydrogen gas by itself, and it could well be that you are bleeding off - together with some air of course.
Believe it or not, a favourite trick is to see if it lights....I kid you not!
If there's a lot of grot in the system, then it could be powerflush time, but I sorted mine by taking each radiator into the garden and flushing it out with a hose.
It doesn't matter if your system is oil or gas here.
John

 

[bernardgreen]

Believe it or not, a favourite trick is to see if it lights....I kid you not!

CAREFUL

as well as hydrogen it also produces oxygen ( from the electrolosis of water ) and the mixture is in the right ratio for very rapid combustion, if it wasn't that some of the oxygen remains dissovled in the water then the ratio of hydrogen to oxygen would be perfect for an explosive combustion. It is unlikely the flame would propagate through the bleed valve into the radiator but if it did while there was still hydrogen and oxygen mixture in there then BOOM

 

[Gogs33]

Thanks Burnerman, Bernard. Yes I recall my chemistry and the hydrogen 'pop' test. I did want to take my rads off to flush but had difficulty getting the first off so left it (followed a good on-line guide). If I can't get a service I'd like to at least put the anti corrosive in but as I said I'm used to putting it in the expansion tank the oil boiler doesn't have that so I'm stumped!

Cheers...Chris

 

[Burnerman]

Combi boiler Chris?
No worries, close a radiator off, disconnect and flush it, and add an inhibitor such as Fernox F1 which is a gel, injected through a bleed valve hole.
Mind you, the whole system needs to be cleaned out for the inhibitor to do its stuff.
John

 

[Gogs33]

It's a Heatslave II systen, fairly old but it has a 'top-up' line on it to ensure the system pressure is maintained. It was low when I moved in so I opened it up until the pressure was ok and then shut off. If I open the drain or a valve on the lowest rad could i flush the system using the 'top-up' line ?

 

[Burnerman]

Good bit of kit, the Worcester Heatslave! Keep it around the 1 bar mark (cold)....that's the central heating pressure and nowt to do with the domestic hot water. As the heating is used, the pressure will increase a few psi.
Every time you open a radiator valve, the pressure drops - which you replenish using the filling loop (top up line).
This injects mains cold water into the radiator return circuit, and can be used for flushing to some degree. However, its not a good idea to introduce fresh water willy nilly as is contains oxygen which promotes corrosion within.....can't win, huh?
For me, its every radiator out for a garden flush - but that's really a summer job!
John

 

[Gogs33]

Ok thanks John. I will try harder next year. So far I've only topped the system up once and will bear your comments in mind.

Regards...Chris
ps The vent cap for my oil tank arrived but it's not quite large enough for the hole. I've made a temporary adaption and it's certainly better than what was there before but I'll need to find something better to keep it in place - possibly a piece of Upvc pipe?

 

[Burnerman]

Yep, do what you can to keep the water out as that will give the burner oil pump a hard time......try to cobble something up with pipe, jubilee clips or whatever.
John