12
SECTION 6 SERVICING
6.1
GENERAL
To ensure the continued safe and efficient opera-
tion of the appliance, it is recommended that it is
checked and serviced at regular intervals.
The frequency of servicing will depend upon the
particular installation conditions, but in general,
once per year should be adequate.
It is the law that any servicing work is carried out
by competent person such as a Vokera engineer,
an approved service agent, British Gas, or other
CORGI registered personnel.
The following instructions apply to the appliance,
but it should be remembered that the domestic
hot water system will also require attention from
time to time.
6.2
ROUTINE ANNUAL SERVICING
●
Check the operation of the appliance and ensure
it functions as described in section 7.
●
Compare the performance of the appliance
with its design specification. The cause of any
noticeable deterioration should be identified
and rectified without delay.
●
Thoroughly inspect the appliance for signs of
damage or deterioration especially the flue
system and the electrical apparatus.
●
Check and adjust – if necessary – all burner
pressure settings (see 7.3).
●
Carry out an analysis of the flue gases (see
7.4), and visually check the condition of the
entire flue assembly.
●
Compare the results with the appliance design
specification. Any deterioration in performance
must be identified and rectified without delay.
●
Ensure both flue venturis are clean and free
from any debris or obstruction.
●
Ensure both the burner and heat exchanger are
clean and free from any debris or obstruction.
●
Inspect all joints for signs of leakage and repair
if necessary.
●
Refer to the commissioning section and/or re-
placement of parts section for detailed
instruction if required.
6.3
REPLACEMENT OF COMPONENTS
Although it is anticipated that this appliance will
give years of reliable, trouble free service, the life
span of components will be determined by factors
such as operating conditions and usage. Should
the appliance develop a fault, the fault finding
section will assist in determining which component
is malfunctioning.
6.4
COMPONENT REMOVAL PROCEDURE
To remove a component, access to the interior of
the appliance is essential. Isolate the appliance
from the electrical supply and remove the fuse.
And when necessary, close all service valves on
the appliance, remove the appliance casing as
described in section 4.7.1, drain the water content
from the appliance via an outlet or appropriate
drain point. Ensure some water absorbent cloths
are available to catch any residual water that may
drip from the appliance or removed component.
Undertake a complete commissioning check as
detailed in section 5, after replacing any
component. ALWAYS TEST FOR GAS
SOUNDNESS IF ANY GAS CARRYING
COMPONENTS HAVE BEEN REMOVED OR
DISTURBED.
6.5
NTC THERMISTORS (see fig. 1)
Carry out component removal procedure as de-
scribed in 6.4.
Locate and remove the ten screws that secure
the air chamber cover.
Remove the air chamber cover.
Disconnect thermistor electrical plug. Using a
13mm spanner slacken and remove the thermistor
and sealing washer. Replace in the reverse order.
6.6
HIGH LIMIT THERMOSTAT (see fig. 1)
Carry out component removal procedure as de-
scribed in 6.4.
Locate and remove the ten screws that secure
the air chamber cover. Remove the air chamber
cover.
Pull off electrical connections from the high limit
thermostat, slacken and remove retaining screws.
Replace in the reverse order.
6.7
FLOW SWITCH (see fig. 16)
Carry out component removal procedure as de-
scribed in 6.4.
Remove the appliance casing as described in
4.7.1. Disconnect the cold water inlet pipe from
the bottom connection of the flow switch.
Disconnect the outlet pipe from the top connection
of the flow switch. Detach the electrical plug/
wires from the flow switch. Slacken and remove
the lock-nut that secures the flow switch to the
lower frame. Replace in the reverse order.
Fig. 16
3
4
5
7
1
2
6
5
1 Screws
2 High limit thermostat
3 Outlet pipe
4 DHW flow switch
5 Locknut
6 Gas valve securing screws
7 Gas valve
