Graphite GR910-B, Instruction Manual

Secondary Air controls are in the fully open position, 
will provide limited heat output. Check that any  
permanent air vent fitted to supply the extra  
combustion air required for the stove has not been  
accidentally blocked. Remember there should never 
be an extractor fan in the same room as a stove. 
A simple way of confirming whether or not the stove 
is receiving enough combustion air is to open a  
window in the same room as the stove. If this  
improves the problem then this would certainly 
indicate that the stove is being starved of combustion 
air and the advice of the original installer should be 
sought.

• Causes: Blockages

 When safe to do so, examine 

the flue-way above the baffle plate as well as the flue 
liner or chimney system, either through the stove or 
via any inspection hatches. Clear any soot blockages. 
Excessive deposits could also indicate a poor choice  
of fuel or that the chimney or flue itself also needs  
cleaning more often than previously thought. 

• Causes: Circulation Pump

 This may need  

re-adjusting to slow down the system’s flow because 
it does not provide the water with a slow enough  
passage through the stove’s boiler to heat up the  
water sufficiently. This in turn prevents the fire  
chamber from ever reaching a good operating  
temperature. It could also be that the central  
heating system may need to re-balanced at the same 
time

.

 See pages 22 and 26 

GLASS STAINING OR BLACKENING

Glass can be cleaned easily if it is undertaken regularly 
and the deposits are not allowed to build up.  
A proprietary stove glass spray or gel is strongly  
recommended.

• Causes: Air Controls

Ensure that you fully  

understand how the Airwash system works and that 
you have determined, through some trial and error 
that you have the correct balance between the  
Primary, Secondary and Thermostat Controls that your 
stove needs. Generally, try to use more Secondary Air 
when burning wood as this air flows down and over 
the glass to help burn and wash away any particulates 
that have accumulated there. 

• Causes: Poor fuel

 Burning damp or unseasoned 

wood will cause the glass to stain as the moisture 
from the fuel considerably reduces the fire chamber 
temperature reducing the effectiveness of the  
Airwash system. ‘Green’ wood will also encourage 
sticky deposits on the glass which will prove difficult 
for the impaired Airwash system to remove.

• Causes: Continuous low burning 

Continuously 

burning your stove with a very low flame, such as 
slow overnight burning will also cause this problem 
because the Airwash does not get hot enough and 
some blackening of the glass should be considered a 

because draught stabilisers limit the exit of flue gases 
from the stove, they should only ever be specified,  
fitted and subsequently tested by an approved  
installer.

• Causes: Fuel 

The fuel itself may be of poor quality. 

For example pine and other softwoods used in the 
building trade will burn much quicker than a good 
hard wood log, such as Oak. 

• Causes: Faulty Door Seals 

The rope seals around 

the fire chamber door could have become worn and 
may not create the air-tight seal needed for the  
Primary and Secondary Air controls to function  
correctly. When the stove is cold, you can easily check 
this seal by placing strips of paper at various points 
between the door and chamber and checking that 
when the door is closed it grips this paper. Any paper 
which can be removed easily would indicate  
a weakness of the door seal in that particular spot, in 
which case a complete new rope seal should be  
fitted. 
 

STOVE NOT PROVIDING ENOUGH HEAT

This problem is also usually indicated by dull orange 
lifeless flames and wood that remains black when 
burning instead of light grey. 

• Causes: Poor fuel

 Poor heat output is more than 

likely caused by poor fuel, such as ‘green’ or  
unseasoned wood or even wet wood. We cannot 
over-estimate how critical it is to use fully seasoned 
dry wood in a boiler stove. The easiest way to check 
whether your wood is fully seasoned is to invest in 
a moisture meter specifically designed for testing 
wood fuel. These are relatively inexpensive and can be 
purchased from your stove dealer. When you bear in 
mind that seasoned wood with a moisture content of 
less than 20% will give you approximately 50% more 
heat than unseasoned wood, a moisture meter is a 
modest investment which will more than pay for itself. 
Wet or unseasoned wood introduces unwanted  
moisture into the fire chamber, again, this is more  
problematic with boiler stoves which are already  
operating at a lower temperature because of the  
‘radiator’ affect of the boiler. Wet wood reduces the 
boiler stove’s fire chamber temperature and thus the 
effectiveness of the air wash system. In addition it will 
cause problems of increased soot and harmful  
creosote deposits within the flue system. 
Softwoods such as Pine produce significantly less heat 
output than hardwoods. 

• Causes: Air controls 

Ensure that you fully  

understand the difference that using the Primary,  
Secondary and Thermostat controls make to the  
performance of the stove and how they need to be  
balanced to determine the best way to burn your fuel. 

• Causes: Inadequate Combustion Air

 A stove 

starved of combustion air, even when the Primary and 

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