Rayburn Rembrandt open fire

twiglet98

My house is a 1920s farm cottage, timber framed with poured concrete infilled panels. The chimney is concrete, thought to have been cast in a single piece. A Rayburn Rembrandt cast iron open fire was already installed when I moved here 21 years ago. There is oil central heating by radiators so the fire is not essential, but I have to reduce what I spend on oil and would like to use the fire more.

Previous owners said they burned wood or coal, whatever they happened to have (vague in all areas, as I have found to my cost over the years!). I have only ever burned wood.

Swept last month by a new, cheaper sweep, who said these fires always fall to bits. He said there was some tar in the chimney from burning softwood (deal?) that I get free from work, and recommended using Hotspot chimney cleaner twice a week.

The bottom grate has a hole in it which is covered with an old iron gully grid. The firebricks are all broken and only the bottom few inches remain. I'd love a stove with doors, a stove which would burn all night and still be warm in the morning. However, I can't afford to replace it and wondered if it's worth buying new firebricks - I guess they need professional fitting - so I googled the model, and found a PDF online of the user manual.

It says: RECOMMENDED FUELS
Welsh Dry Steam Coal (Large Nuts), House Coal - Trebles
or Doubles.
Manufactured smokeless fuels such as Coalite, Homefire,
Homefire Ovals, Newflame and Supacite.
IT IS NOT RECOMMENDED TO BURN WOOD.
IMPORTANT: FUELS SHOULD BE ADEQUATE IN SIZE.
FUEL SMALLER THAN 1” DOES NOT GIVE
SATISFACTORY RESULTS. FUEL SHOULD BE KEPT
DRY AND STORED UNDER COVER.
PETROLEUM COKE SHOULD NOT BE USED.

It does not say WHY it is not recommended to burn wood. None of the three sweeps I have used over the years has advised me not to burn wood. Can anyone explain the reasons?

I know wood should burn on a bed of ash, and that can't happen with a grate in place, without damaging the grate. I assume that's why my grate has a hole in it, but is that the only reason the makers say not to burn wood?

Also, in the manual there is advice on overnight burning, which says a light covering of slack helps to slow down the rate of burning. What is 'slack'?

Thanks...

Greenfires

Not entirely sure why they'd advise against wood, apart from the fact that it's sort of "designed" as a coal/smokeless thing. The Hotspot stuff basically converts the hard shiny tar into a crispier version that will often fall off itself, or at least will be much easier for the sweep to remove - but don't look at it as an alternative to a sweep!

Slack is basically very fine coal and coal dust - sort of stuff you'd find in the bottom of the coal bunker. It basically just chokes the fire - and will probably produce a lot of smoke at the same time. In my coal burning days - a long time back - we used to stoke the fire up, and then cover it with ash from the ash pan - this would keep it in all night. Not a very green option though!!

Andy

suki1964

Your grate could also have a hole in it from the ash pan not being emptied often enough- we get through one or two a year in work because some staff think fire cleaning is beyond them. Red hot ashes building up under the grate and a red hot fire in the grate and the grate will fall to bits really quite quickly

Slack is fine coal - not quite dust - like gritty sand. A trick here is to dampen it before using it. You just cover the whole of your fire with slack and it should keep it in over night, just needing a few kindlers to get a fire going again in the morning. You do need to put it on a good hot fire as otherwise it will smoke

twiglet98

Thanks, is slack not something I'd buy, then? It would be a natural addition to a delivery of coal - not smokeless fuel? However, I really do just want to burn wood, which I enjoy handling, and can collect plenty for free. My concern really is that until googling the model to research replacement firebricks, I had never seen a user manual, and didn't know the manufacturers did not recommend burning wood. It is actually described as the "Rayburn Rembrandt solid fuel open fire".

It's alight now, the ashpan is very full, with a bed of ash over the grate (helping it disintegrate!) and it will be Saturday morning before I can empty it. Puzzled as to why I should not burn wood, I'm trying to fathom a way of using the fire without the grate in place... but without the grate, surely it would need an ash box several inches deep.

suki1964

There are those who just burn on the floor of their fire on a good bed of ash. I used to go with a guy whos fire was just that - open space with a pile of logs burning away

Its because you have the grate your stove is for coal and if you dont keep the ashes down you will burn through grate upon grate. Burn wood by all means but accept you will be burning it fast as there will be too much air getting to it and you wont get the heat out put you would with using solid fuel

If you remove the grate then you just leave the ashes and just shovel out when need be ( you need a hot ash can for obvious reasons)

Slack is bought from the coal man. Its quite dear for what it is but you get it nice and damp and you wont need too much so a bag should last a while

A._Badger

Suki is right but just to clarify, because wood burns cooler than coal and smokeless fuel, you can let the ash build up over the bars of the grate and burn wood on a bed of that ash. Just don't try the same thing with coal or smokeless, which burns hot enough that without a draught of air coming from beneath, through the bars, they will simply, if gradually, melt.

If it were me, I wouldn't worry about the recommendation not to burn wood (which seems difficult to explain on any rational basis as it's a cooler burn). But it is very important to make sure your wood is properly seasoned. The tar build-up in your chimney is almost certainly due to burning wood which isn't sufficiently dry.

twiglet98

Thanks for all the advice. I saw rectangular blocks of firebrick in Wilkinsons today much cheaper than the ones online that are shaped to fit this fire, though I can't see how to cut the cheap ones, or even how I'd fit either sort. They sell grates too, incidentally, but they were very lightweight and flimsy.

In terms of making it burn slower and for longer, it seems I should be looking at something like Homefire smokeless - but I get a lot of wood free from the farm where I work, also gather it all year from the woods. I like handling wood (though I still need a powered saw) and I have a fair pile in the barn to work through. I might just get a small bag of smokeless to compare how long the fire lasts. If I clean out the present deep bed of ash, which covers the grate, I suppose I could save it and put it back if I don't like the smokeless fuel!