3.1 SERVICING SCHEDULE
CLEANING PROCEDURE
1. Remove the casing.
2. Visually check the appliance for signs of leakage.
3. Remove the flue manifold.
4. Remove the fan.
5. Remove the burner.
6. Refit the sump outlet cover.
7. Clean the heat exchanger by pouring warm water across
the whole heat engine to flush deposits taking care to
avoid pouring water over the electrode.
8. Check the electrode for damage and clean using an
abrasive cloth. Check and adjust the spark gap. Replace
the electrode if damaged.
9. Clean out the sump outlet to ensure any debris is
removed.
10. Remove and clean the condensate trap and re- prime the
trap before re-installing.
11. Check the DHW filter for blockage.
12. Re-assemble the components in reverse order.
13. Carry out post service checks on the combustion circuit.
See General below.
14. Check the system water quality in accordance with
BS7593:2019.
15. Complete the service record in the Benchmark section.
Do not operate the boiler if the front panel is not fitted
.
PRELIMINARY INSPECTION
1. Light the boiler and carry out a pre-service check, refer to
the fault finding chart.
2. Check the flue terminal (and terminal guard if fitted) for
damage and obstruction.
3. Check combustion by connecting the flue gas analyser to
the flue gas sampling point as shown in the diagram and
measure CO and CO
2
at maximum rate. Set the boiler to
Maximum and Minimum heat inputs.
Refer to Section
2.34
If the CO / CO
2
ratio is greater than 0.004 please proceed
to “Cleaning Procedure”.
If the CO / CO
2
ratio is less than 0.004 please proceed to
“Check Procedure”.
CHECK PROCEDURE
1. Check all water and gas joints for signs of leakage.
Remake any suspect joints ensuring a gas tightness
check is carried out if applicable and the water system is
correctly refilled, vented and re-pressurised.
2. Proceed to “IMPORTANT”.
IMPORTANT
1. If, for any reason, the condensate trap has been removed,
ensure the trap is refilled with water before re-assembling.
2. After completing the servicing or exchange of
components, always ensure all gas valve connections
are gas tight with a gas soundness check up to the gas
control valve.
3. When work is complete the front panel MUST be correctly
refitted, ensuring that a good seal is made.
4. Complete the service section in the Benchmark
Commissioning Checklist.
GENERAL
During Servicing, and after any maintenance or change of
part of the combustion circuit, the following must be checked:
-
The integrity of the flue system and the flue seals.
-
The integrity of the boiler combustion circuit and the
relevant seals.
-
The operational (working) gas inlet pressure at maximum
rate.
-
The gas rate.
-
The combustion performance.
To ensure the continued safe and efficient operation of the appliance, it is recommended that it is checked at regular intervals
and serviced as necessary. The frequency of servicing will depend upon the installation condition and usage but should be
carried out at least annually.
For the latest copy of literature, visit our website Keston.co.uk.
WARNING:
Servicing can only be carried out by Gas Safe Registered Engineers. In IE servicing work must be carried
out by a Registered Gas Installer (RGII)
Always turn OFF the gas supply at the gas service cock, and switch OFF and disconnect the electricity supply to the
appliance before servicing
Combustion testing must be carried out by a competent person using a combustion analyser conforming to
BS EN 50379-3:2012.
Section 3 - Servicing
Flue
Sampling
Point
Air
Sampling
Point
Ensure all caps and
seals
are re-fitted after
use.
56.5
65
37.5
38
Installation and Servicing
SER
VICING
