![]() | Boiling Point No. 17 - December 1988 |
Extract from "Improved Wood, Waste and Charcoal Burning Stoves", "A Practitioner's Manual by ITDG, 1987, pp 230, £9..95 from IT Publications Ltd.
Repair Guidelines for Use in the Field
The first step is to check that the stove to be repaired has been constructed according to the original plan(s). If the stove does not follow the original plan this will most probably be the reason for unsatisfactory performance, given the same operating conditions (pots, fuel, chimney height, etc.) for the original stove and the stove being repaired. Determine whether any modifications have been made and the reason why.
The next step is to discover, by interview, what problems the user may have with the stove, and to observe a fire burning if possible.
The common problems which will be encountered, their causes, and the various solutions available to remedy them, are tabled below.
Table 1: Multi-Pot Chimney Stoves
Problem |
Cause |
Solutions |
Always slow to cook |
Firebox too deep and names not touching first pot. |
Reduce firebox height by raising the floor. |
Low draught and very little flames. |
Increase tunnel size* |
|
High draught and flames flaring straight out without good pot contact. |
Increase baffle gap |
|
Increase chimney height. |
||
Reduce baffle gap |
||
Decrease back tunnel size |
||
Decrease front tunnel size |
||
Decrease chimney height. |
||
Slow cooking problem developed after a few hours use. |
Clogged chimney chimney cap or tunnel |
Clean out chimney chimney cap and tunnel. |
Burning too much fuel and burning it quickly |
High draught |
Reduce baffle gap |
Decrease back tunnel size* |
||
Decrease front tunnel* |
||
Decrease front door area* |
||
Decrease chimney height |
||
Smoke always coming out of the front door |
Low draught |
Increase tunnel size* |
Increase baffle gap stove |
||
Increase chimney height |
||
Smoke coming out of front door of stove when windy |
Poor chimney placement as wind is forced down chimney |
Change chimney position |
Not enough heat to second pot |
Baffle gap is too great and flames do not have good pot contact |
Decrease baffle gap |
First tunnel is too small and total power output is low |
Enlarge first tunnel |
|
Baffle gap is too small and total power output is low |
Increase baffle gap slightly |
|
Baffle angle is wrong |
Change angle* |
|
Too much of total heat going to the second pot |
High draught |
Reduce baffle gap |
Decrease back tunnel |
||
Decrease front tunnel |
||
Decrease chimney height |
||
High fuel consumption |
Draught too large, or small |
Increase or decrease the height or position of baffles |
Check diameler/height of chimney |
||
Increase or decrease fuel entrance or air entrance* |
||
Pots wrong design or size |
Check pot with stove design recommendations. |
|
Combustion chamber too large, or too small |
Check combustion chamber shape and size in design recommendations. |
|
Cooking performance poor ie. Slow to cook |
Power output low |
Check moisture content of fuel |
Poor heat transfer |
Increase fuel load Increase draught, reduce baffle height, increase chimney height |
|
Check draught |
||
Difficult to ignite |
Cold or wet stove |
Light fire with as much paper and kindling as possible |
Blocked chimney or flue |
Clean stove |
|
Wet wood |
Use drier wood to start, adding wet wood only when stove is well alight |
|
Difficult to burn wet wood |
Insufficient draught |
Increase chimney height |
Decrease baffles |
||
Clean stove |
||
Stove very smoky |
Insufficient draught |
Increase chimney height |
Decrease baffles |
||
Fuel load too large |
Reduce fuel load |
|
Excessive soot deposits |
See 'Stove very smoky' |
Clean stove and chimney |
Insufficient heat to second pot |
Insufficient draught |
Increase chimney height |
Decrease baffles |
||
Baffle wrongly positioned or wrong size |
Check position and size of baffle |
|
Excessive heat to pots |
Too much draught |
Increase baffles |
Decrease chimney height |
||
Smoke exits from the fuel entrance or fire burns back out from the entrance |
Wrongly positioned chimney - wind blows down it. |
Re-locate chimney or cover with cowling |
Insufficient draught |
Increase chimney height |
NOTE:
* These solutions not applicable for all pottery stoves
+ These solutions not applicable for pottery stoves not surrounded by mud