Remove the plug from the combustion test point, insert the analyser probe
and obtain the CO/CO
2
ratio. This must be less than 0.004. If the combus
tion reading (CO/CO
2
ratio) is greater than this, and the integrity of the
complete flue system and combustion circuit seals has been verified, and
the inlet gas pressure and gas rate are satisfactory either:-
Perform the "Standard Inspection and Maintenance" .
Perform "Setting the Gas Valve" .
Replace and set the gas valve.
1
Combustion test point
2
Incoming air for combustion test point
9.2
Standard inspection and maintenance operations
9.2.1
Annual Servicing
Warning
Ensure that the boiler is cool. Ensure that both the gas and electri
cal supplies to the boiler are isolated.
Caution
Always examine any seals or gaskets, replacing where necessary.
Where a seal or gasket is supplied with a spare part it should be
used, irrespective of the condition of the original. Use only original
spare parts that are intended for use with this type of boiler.
Important
When performing any inspection or maintenance, personal protec
tive equipment must be used where appropriate.
1. Ensure that both the gas and electrical supplies to the boiler are iso
lated and that the boiler is cool.
2. Remove the case front panel and hinge down the control panel.
See
Specific maintenance instructions, page 55
3. Disconnect the pipe from the top of the condensate trap and the
drain pipe from the condensate drain pipe connection. Undo the
screw securing the bracket and trap to the boiler lower panel.
4. Remove the trap. Take care not to spill any residual condensate on
the controls and P.C.B. Thoroughly rinse the trap and examine the
gasket on the trap base, replacing if necessary.
5. Remove the clip securing the gas feed pipe to the air/gas venturi on
the fan. Disconnect the pipe. Do not break the joint between the pipe
ang gas valve unless necessary.
6. Disconnect the electrode lead and the fan electrical plug.
7. Undo the four nuts retaining the burner / door assembly to the heat
exchanger.
8. Carefully draw the burner / door assembly forward and remove.
See
Checking the burner and cleaning the heat exchanger, page 54
9. Clean any debris from the heat exchanger and check that the gaps
between the tubes are clear.
10. Inspect the burner, insulation and position and condition of the elec
trode, cleaning or replacing if necessary. Clean any dirt or dust from
the airbox.
11. Carefully examine all seals and gaskets, replacing if necessary.
Look for any evidence of leaks or corrosion and if found determine
and rectify the cause.
12. Reassemble in reverse order.
Fig.45
Flue adaptor test points
PN-0000363
1
2
Fig.46
Remove the condensate trap
PN-0000381
9 Maintenance
7678846 - A - 22052017
53
