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18.0 SERVICING THE BURNER - continued
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 thermocouple needs
replacement.
The gas valve is a non-serviceable item. If this needs replacement,
remove the indicator plate then the securing screw holding the valve
bracket in place, remove all pipe unions, and the complete valve.
Replacement must be original manufacturers parts.
Re-assemble in the reverse of removal. Ensure setting pressures are
as stated in Section 3; Appliance Data.
19.0 PILOT ASSEMBLY
WARNING: NO ADJUSTMENTS ARE TO BE MADE TO
THE ODS PILOT SYSTEM. TAMPERING WITH THIS
SYSTEM CAN BE EXTREMELY HAZARDOUS.
Remove the casing, glass panel and burner unit (as per servicing sec-
tion), lint arrestor and pilot unit by using a screwdriver to remove the
retaining screws.
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 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 dangerous and can have a serious unseen effect on
safety and therefore MUST not be done. Replacements must be origi-
nal manufacturers parts. Re-assemble in the reverse of removal.
Ensure setting pressures are as stated in Section 3; Appliance Data.
20.0 CATALYSTS
It is recommended that the catalysts are inspected for signs of damage
and dirt during routine servicing procedures. The expected life of the
catalysts is in excess of 11,000 hours (10 years of normal use). After
this time the catalyst should be replaced.
If there are any deposits of dirt or soot on the catalysts 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 catalyst may be checked using a combustion
gas analyzer as follows.
Important: The temperature of the gases emitted by the catalytic
converters is in excess of 700
may damage some types of gas analyzers. If in doubt consult the
equipment manufacturer.
F. Measuring gas of this temperature
o
Ignite the fire as per the operating instructions, and run at maximum
setting for 15 minutes. Position gas sample probe directly over a cata-
lyst via the outlet grille, on top of the appliance. Record the carbon diox-
ide (CO2) concentration and then the carbon monoxide (CO)
concentration as displayed by the analyzer - also noting the units in
which the values are expressed. Most analyzers 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 per-
centage. 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.
CO (%)
CO2 (%) = ratio
The combustion ratio of the gasses emitted by the catalytic convertor
should not exceed 0.0015.
If replacing, firstly, remove the decorative fire frame as described in
section 8.0. The catalysts are located on the top of the internal firebox
and can be removed be unscrewing the retaining nuts securing the
clamping plate. Remove the catalysts and the seals and discard.
Refit a new catalyst and seals in reverse order, ensure the catalyst and
door have a good seals.
21.0 TESTING FOR FIREBOX LEAKAGE
Appliances that are several years old or have been extensively disman-
tled should be checked for soundness. It is important that all the prod-
ucts of combustion pass through the catalytic convertors 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 gasket faces, especially around
the door. It is important to note that the appliance can never be expect-
ed 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.
22.0 CLEANING
WARNING: TURN OFF THE UNVENTED GAS ROOM
HEATER AND ALLOW TO COOL BEFORE CLEANING.
GLASS PANEL -This can be cleaned with a suitable glass cleaner, or
proprietary ceramic hob cleaner. Test on a small area first.
PAINTED AREAS - These can be cleaned using a dry cloth.
STAINLESS STEEL AREAS - These can either be cleaned using a
proprietary stainless steel metal cleaner or baby oil. Test on a small hid-
den part of the stainless steel before cleaning. Always clean in the
direction of the grain.
8
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