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Boat stove problems

I have a Valor Willow stove on our boat. We seem to have an air problem, it doesn't draw very well. I have checked Valors website and they recommend a flue/chimney length of at least 4.5 metres. Other manufacturers recommend similar length flues. How do I get my stove to burn better, with the standard boat flue/chimney?

Asked by: Tom Brady  | 7.39pm, Sunday 12 February

WW says:

One of the reasons that the new standards suggest double-walled flues is to increase the draw on stoves with a small length flue on boats, as keeping the temperature in the flue higher helps the stove draw.
It might be worth considering a longer external chimney for when tied-up, and a shorter one for when cruising; although how much difference this will make it questionable.
It may be worth checking that the flue is clear (no soot deposits), especially if there are any bends in the system, and also where it passed through the deck fitting.
Inside the stove, make sure that there is nothing restricting the passage of gases- such as the diverter plate being out of place inside the stove.
The other main area might be to try different fuels. Starting on wood, then converting to solid fuel (or vice-vera) may suit your stove. Different solid fuels perform better or worse in different stoves, so a degree of experimentation might be useful. Bigger nuggets often work better in low-air situations, and wood usually burns very well.
SOrry not to be able to give a more definate view. Speaking to one of the suppliers might be able to help you- or to configure the internal fittings of the stove differently- alas, I don't have personal experience of this stove. Some domestiv based sf stoves just don't seem to give good service on boats alas: not sure if this is the case here. Some are far more tolerant of short flues than others. The most popular stoves are there for a reason, as they work well- like the Morso Squirrel, etc.

Mark Langley  | 3.45PM, Wednesday 15 February

I think one of the reasons that the Squirrel is so effective, is the large range of air inlets that can be used, which possibly give a greater possibilty of running. I will have a look into the stove design in detail, to see if I can find anything else out for you.
The double skin flue does make a big difference to the running of the stove and can reduce carbon monoxide levels in the flue gas as well.

Mark Langley  | 8.31PM, Wednesday 15 February

If you have a rain cap on the chimney, it will restrict the draw slightly, it might be worth considering one of the rotating angled caps ( sometimes with a bird motif) that are said to increase the draw.
What is the flue diameter? Sometimes stoves are fitted with flues that are of smaller diameter than the stove outlet, to the detriment of the operation. The flue diameter should never be smaller, 5 or 6 inch is normal.
A word of warning, do not fit an insulated flue pipe without an insulated roof collar. The increased flue temperature could set fire to the roof lining.

Rupert Smedley  | 10.50AM, Monday 20 February

Readers say:

Thanks for your suggestions Mark. I've looked at Morso's website and they recommend a flue of at least 4.0 metres. I've tried various fuels and wood seems best, but some of the wood waste briquettes are more like coal and don't burn well. From the Morso website it looks as though your suggestion of the double skin flue is worth following. By raising the flue temperature the draw should improve. I suppose I could consider a 3.0 metre chimney on top of the boat if all else fails!

Tom Brady  | 7.28PM, Wednesday 15 February

Thanks for your suggestions Rupert, I have just come home from the boat. I think the flue is 6inch diameter. I have a cap on the flue, so removing that would be easy to try. The rotating type of cap is a possibility, I can see how it could improve the draw. Thanks for the advice on the double skin flues, it's somethig I hadn't thought of. I did notice another boat at our moorings with a 6 foot length of stainless steel pipe poking out of the roof flange, I think they've made a total length of around 11 foot.

Tom Brady  | 8.30PM, Wednesday 22 February

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