Airlock with no leak in home heating system (oil)

Does it burn with a clear flame? I seem to be able to light the gas coming off the bleed valve of the radiator - I can hear it burning and feel the heat but see no flame (in daylight).

This is getting very interesting! You might be on to something

tentimes said:

Does it burn with a clear flame? I seem to be able to light the gas coming off the bleed valve of the radiator - I can hear it burning and feel the heat but see no flame (in daylight).

This is getting very interesting! You might be on to something

Click to expand...

Yes hydrogen burns with an invisible flame.

So I may have an electrical problem in the boiler.

At this point, what type of tradesman do I need?

And can you say any more about what the problem might be? Some sort of short or something? A faulty earth?

tentimes said:

So I may have an electrical problem in the boiler.

At this point, what type of tradesman do I need?

And can you say any more about what the problem might be? Some sort of short or something? A faulty earth?

Click to expand...

More likely an electrical problem in the house.
Could be the central heating pump as well.

Get a spark in to test the system pipework for electrical current leaks and correct continuity bonding.
Excessive corrosion in the rads/system can also created hydrogen as well as electrically induced electrolysis.
Unprotected/old Mixed metal systems can be more susceptible to creating hydrogen gas through electrolysis.
Do you have adequate inhibitor added to your system, get a professional to check concentrations.

Several of the radiators burst one winter and were soldered back together instead of replaced - could this be leading to the electrolysis?

We are very short of money but it looks like maybe this could be the culprit and we will have to save up to replace them (times are tough).

They have been like this for several years but the airlocking only started about a year ago.

EDIT: Not sure what an inhibitor is btw.

Depends what metal was used to solder, lead based solder could add to the issue as it's another metal that could react with another within the system. Inhibitor is a fluid added to the central heating system that minimises the conditions that can cause corrosion, reducing the likelyhood of electrolysis between different metals/materials.

tentimes said:

Several of the radiators burst one winter and were soldered back together instead of replaced - could this be leading to the electrolysis?

We are very short of money but it looks like maybe this could be the culprit and we will have to save up to replace them (times are tough).

They have been like this for several years but the airlocking only started about a year ago.

EDIT: Not sure what an inhibitor is btw.

Click to expand...

No sounds like a good old short. Cable letting electric straight into the piping.
Little bits of solder here or there are not going to lead to the amount of gas you describe. It needs a steady small current.

I'm no expert, but this is what happened to my system this year....

Firstly we go back to March last year, when 2 of my upstairs radiators needed bleeding regularly. Then one double rad downstairs would gurgle away for 10-15seconds every time the boiler and pump started, but no amount of bleeding would solve that - clear water just poured from it all the time.

November came and the heating went back on and the bleeding and gurgling started again. Then we starting getting trickling noises in our bedroom as the water was entering the rad. This also started happening in the hall radiator and before long two more radiators were doing it. Radiators also seemed not to get as hot as they used to.

I doubted it was dirty in the system as the system was thorough flushed out in June 2013 and fresh inhibitor added.

The psychic side of me decided to pay a visit to the header tank and there I discovered what I can only describe as a transparent gel-like globule (looked like a small amount of wall paper paste) floating about, it wasn't easy to see, I just has a really strong torch with me. I scooped it out and thought no more. A few weeks later I thought i'd just check again and this time found my tank had what looked like a Yorkshire pudding floating on top!

I got in touch with Fernox and asked their advice, they told me I had either a bacterial or fungal infection in the CH water and needed to add a biocide to the header tank after thoroughly cleaning it out (that was yucky).

That was three weeks ago and the system is now running sweetly - the best it's been in a long time! I haven't had to bleed any rads, no noises from the system and rads getting nice and hot - it seems even your heating system can get a snotty cold!

I should add that Fernox told me that this "infection" results in the build up of scum and this inturn produces gases in the system, hence the bleeding required and gurgling noises - also made worse by the scum/globules.

Wow. Thanks Ronob - I might not have the same thing, but the more I read the more I think this problem is starting at the header tank one way or another.