Gas fire problem

[brenda]

In the living room I have a small gas fire with artificial coals at the bottom.It is not state of the art , at least 15 years old , but a cracking little fire in the winter.
The fire fits in to a space in the surround. The walls of the space are brick lined and are a bit discoloured now through use.Have noticed recently a deposit of black soot like powder on ,one side of the brick lining , the other half of the lining is just as it was.

Any suggestions what may be causing this would be really helpful, and what if anything can be done. Many thanks .Brenda.

[DTCwordfan]

gas contains carbon, just like any fire, (CH4 for methane and C2H6 for ethane) you may need your flue cleaned if it hasnt been done in a while

[brenda]

DT-- thank you-- will organise the sweep.

[DTCwordfan]

not a bad thing for safety and some household policies like it to be done annually - read your policy fine print carefully

[brenda]

DT----Thanks again --will do that.

[The Builder]

I don't know if your fire can be serviced/adjusted ............. it's a few years old. I wonder if it's not burning efficiently. Worn jet or something? Do you have the manual?

[DTCwordfan]

could be - but the flue does need cleaning if there is carbon black in there. N-Gas is not pure and once you get to carbon molecules above three (propane) and C4 (butane) you can get isomers being formed....these do not necessarily burn clean and soot is essentially a gradual build up of the carbon crud (not a scientific word) - and of course is inflammable if enough heat gets it going.....and hence the chimney fire. I used to be the marketing director gas for one of the mid sized players

[ixion]

I don't wish to be alarmist but soot at a gas fire is indicative of incomplete combustion - your fire may be producing CO as opposed to CO2 - I'd get it checked by a Gas Safe regd engineer before using it again.

[DTCwordfan]

true there is a small risk of that - the issue is how quick it has accumulated - if sudden that would suggest the burner and the risk is higher.......

[AlBags]

I think you'll find that the shape of the vortex/draught causes uneven sooting.
There should be a small throat vent at the bottom of the register plate behind the fire, which the flue/outlet seals through.
Is this a Robinson-Willey Sahara or something like that?

[AlBags]

Gas fires produce quite high flue temps, but are very clean burning.
As a result, a flue/chimney should not need regular sweeping, like if you were buring wood/coal and damp materials.

[brenda]

Thank you for all your time to answer, much to think about here.

Builder -- no manual, British Gas came last year to service the kitchen boiler and I asked the man about the fire. He was not able to find the make or design amongst those listed on his computer and said it was too old probably.
ixion----had thought of Co myself as well , have a CO detector in the same room , which works.
Albags ---more your Heath Robinson I think!

Think I will have to bite the bullet on this one and get something more modern which I can then have serviced.
Thank you all again for your answers.