SERVICING THE BURNER UNIT AND GAS ASSEMBLY (continued)
Remove the pilot and main burner pipes and blow through to dislodge any debris. Now remove the
restrictor elbow and blow through to make sure it is entirely clear.
Unclip the pilot lint gauze and clean with a soft brush. Clean the exterior of the pilot assembly with a
soft brush and blow through the flame ports on the pilot head. Check the aeration holes are free from
lint or dirt. The pilot assembly can be removed if required by disconnecting the electrode HT lead, gas
pipe and unscrewing the mounting screws and lifting away.
The pilot assembly is a non-serviceable item and should not be taken apart. Aeration holes must be
absolutely clear internally for proper operation.
NEVER MODIFY OR BEND THE THERMOCOUPLE TO
MAKE THE PILOT STAY ALIGHT
. Modifications are dangerous and can have serious unseen effects
on safety. If the pilot will not stay lit there is a problem with dirt, the gas supply to it, or the thermo-
couple needs replacement.
The gas valve is a non-serviceable item. If this needs replacement, remove M4 securing screw holding
the valve in place, remove all pipe unions, electrode lead, thermocouple lead and then the complete
valve. Replacement must be original manufacturers parts. Re-assembly is the reverse of removal.
Ensure setting pressures are as stated in Section 2; Appliance Data.
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 spanners 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 speci-
fications 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 dangerous 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 servic-
ing procedures. 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 cat-
alyst. 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. A suitable analyser is a Telegan Sprint 2000 XT
Combustion Flue Gas Analyser.
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 locat-
ed on the top of the internal firebox and can be removed be unscrewing the retaining nuts securing the clamp-
ing 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 fire-
box 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 gasket 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.
8
©
2012 Acquisitions of London
10.1
10.3
10.2
CO (%)
CO2 (%) = ratio
10.4
