PILOT ASSEMBLY
Clean the pilot assembly with a soft brush and blow through. Check the aeration holes are free of any dirt or
lint. Clean thoroughly internally, the connection can be removed from the base of the pilot unit using two span-
ners to make cleaning easier. Do not damage or try to dismantle the pilot injector.
The unit is factory set and the only check necessary is to ensure the spark gap is correct. See specifications for
gas setting.
NEVER MODIFY OR BEND THE THERMOCOUPLE TO MAKE THE PILOT STAY ALIGHT
. If the pilot will not stay
lit there is a problem with dirt, the gas supply, or the thermocouple needs replacement. Modifications are dan-
gerous and can have a serious unseen effect on safety and therefore MUST not be done. Replacements must be
original manufacturers parts. Re-assemble in the reverse of removal. Ensure setting pressures are as stated in
Section 2; Appliance Data.
CATALYST
It is recommended that the catalysts are inspected for signs of damage and dirt during routine servicing proce-
dures. The expected life of the catalysts is in excess of 11,000 hours (10 years of normal use). After this time the
catalysts should be replaced.
If there are any deposits of dirt or soot on the catalyst they should be cleaned with a soft brush and a vacuum
cleaner. If removed for cleaning ensure the seals are in good condition before replacing the catalyst. New seals
will usually be required. The performance of the catalysts may be checked using a combustion gas analyser as
follows. Any analyser used should conform to EN 50379-3.
Ignite the fire as per the operating instructions, and run at maximum setting for 15 minutes. Position gas sample
probe directly over the catalysts via the outlet grille, on top of the appliance. Record the carbon dioxide (CO2)
concentration and then the carbon monoxide (CO) concentration as displayed by the analyser - also noting the
units in which the values are expressed.
Most analysers display carbon dioxide (CO2) concentrations in percentage (%) terms and carbon monoxide
concentration in parts per million (ppm) terms.
In order to calculate the combustion ratio for the appliance (CO/CO2) it is first necessary to express both gas
concentrations in terms of percentage. To convert from parts per million (ppm) to a percentage (%) divide the
ppm figure by 10,000. Examples : 35ppm = 0.0035%, 15ppm = 0.0015%, 5ppm = 0.0005%.
Now divide the concentration of carbon monoxide (CO) expressed in percent by the concentration of carbon
dioxide (CO2) to obtain the appliance combustion ratio.
The combustion ratio of the gasses emitted by the catalytic convertor should not exceed 0.0015.
If replacing, firstly, remove the decorative frame/glass facia as described in section 8.4. The catalysts are located
on the top of the internal firebox and can be removed be unscrewing the retaining nuts securing the clamping
plates. Remove the catalysts their seals and discard. Refit the new catalysts and seals in reverse order, ensure the
catalysts and the glass door have good seals.
TESTING FOR FIREBOX LEAKAGE
Appliances that are several years old or have been extensively dismantled should be checked for soundness. It
is important that all the products of combustion pass through the catalytic converter at the top of the firebox
before leaving the appliance.
The firebox is heated by lighting for a few minutes to provide a flow through the firebox. The burner is then
shut off and a smoke pellet or match introduced at the base of the fire underneath the burner tray. Large
quantities of smoke will emerge from the top of the appliance, but none should emerge from the joints or gas-
ket faces, especially around the door.
It is important to note that the appliance can never be expected to be 100% smoke tight and small quantities
of smoke may be seen in corners of joints and gasket faces etc without affecting safety when the fire is in
operation.
9
10.3
10.2
CO (%)
CO2 (%) = ratio
10.4
