Graphite GR910-B, Instruction Manual

TROUBLE-SHOOTING

CHIMNEY FIRE

If your stove has been installed correctly and you have 
also operated it correctly and regularly carried out the 
recommended routine checks then it is unlikely that 
you will ever experience a chimney fire, which can be 
highly dangerous.
Chimney fires can be detected by an unusual roaring 
sound and / or unusual vibrations coming from the 
chimney breast or the stove itself. The sound is not to 
be confused with the gentle ‘rushing’ sound you may 
normally hear when a stove has a well performing 
up-draught. During a chimney fire you may also see 
sparks or flames exiting from the chimney terminal 
outside.

• Prevention 

If you suspect a chimney fire then immediately close 
the Primary and Secondary Air controls, as well as the 
Thermostat Control, evacuate the building and call 
the Fire Service. 

Never 

open the stove door as this will 

make the chimney fire worse by providing additional 
combustion air. Do not re-enter the building until you 
have been advised by the Fire Service that it is safe.
Do not re-light the stove until the flue system has 
been thoroughly inspected by an approved installer or 
chimney sweep and any necessary repairs have been 
carried out.

• 

Causes: Inadequate cleaning 

Chimney fires occur when soot and creosote have 
built up to such a level that they ignite. It is important  
therefore that your flue system has as many cleaning 
access points as practicable to enable comprehensive 
removal of soot, creosote and other debris. This will 
also minimise the amount of time it takes for a  
qualified sweep to clean the system making the  
system safer and its cleaning more cost-effective in 
the long run. 

• 

Causes: Continuous low burning

To discourage the potential for such soot and  
creosote build-ups, long periods of consistent  
‘slumber’ or overnight burning should be avoided 
or that these should at least be compensated for by 
regular burning on full output for short periods (eg 30 
minutes per day) to help burn off any likely deposits 
before they become problematic. 

• 

Causes: Poor fuel choice 

As previously mentioned 

unseasoned or damp wood or fuel should always be 
avoided as these produce excessive soot and creosote.  
This is particularly problematic for boiler stoves where 
the fire chamber temperatures are much lower than 
in a non-boiler stove and therefore the potential to 
promote the conditions for dangerous deposits from 
damp fuel is much greater.  
 

SYSTEM BALANCE

With all wood burning and multi fuel boiler stoves, 
given their particular heat cycle and the natural gravity 
fed flow, it is extremely important that the radiators 
are balanced to ensure an efficient distribution of heat 
as well as an even heat balance from one radiator to 
the next. The idea is to reduce the flow to the hottest 
radiators so that more hot flow is available to heat the 
coolest ones. The system is ‘balanced’ when there is a 
good hot water flow through every central heating 
radiator.
To undertake this, all of the system valves should be 
set to open (including any lock shield valves (LSVs) 
on the heat leak radiator) and the circulation pump 
adjusted to the correct flow speed. Thermostatic 
radiator valves (TRVs) should also be set to maximum 
to ensure that these are not activated during the 
balancing process. All radiators should be fully bled 
of air and the system should be at full operating 
temperature. Please note it could take the system 2 
– 3 hours, depending on the size of the system and 
the fuel loads, to reach full operation.
The objective is to get a consistent temperature 
difference of approximately 10ºC between the flow 
(80ºC) and the return (70ºC) on each radiator. If the 
circulating pump flow rate is set too high then the 
temperature drop between flow and return will be 
less than 10ºC. Balancing the system means adjusting 
all of the various thermostatic valves, thermostats, 
lock shield valves on each radiator and the circulating 
pump speed to give the desired temperature in each 
room for the least amount of fuel used. This can be 
a time-consuming process, but is well worth it, and 
therefore is best left to an experienced installer.
With the system at full operating temperature and 
all of TRVs fully open, if the temperature drop is 
different from 10ºC but consistent across all of the 
radiators then it will be a simple matter of adjusting 
the circulating pump flow to achieve the desired 
10ºC drop. Slow down the pump flow to increase the 
drop difference and speed it up to reduce it. In reality 
it does not matter if some radiators have a slightly 
smaller temperature drop, hence a higher flow, so 
long as there is enough flow to get all of the radiators 
at a desirable temperature.
Fortunately, a balanced system does not mean 
that all of the radiators have to be set at the 
same temperature. How hot a radiator is once the 
thermostatic valve is operating will depend on many 
variables including the size of the room, how high the 
TRV is set and how big the radiator is. Radiators are 
likely to be slightly hotter at the top than the bottom 
but this will vary from system to system and the 
design of the radiator itself. Provided the temperature 
difference from the top to the bottom of the radiator 
is no more than the 10ºC flow and return difference, 
then this is not generally an indication of a system 
problem.

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