Main 12 HE A, Installation & Service Instructions Manual

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14.0 Servicing the Boiler
42
© Baxi Heating UK Ltd 2014
14.1 Annual Servicing
1. For reasons of safety and economy, it is recommended that
the boiler is serviced annually. Servicing must be performed by a
competent person in accordance with B.S. 7967-4.
2. After servicing, complete the relevant Service Interval Record
section of the Benchmark Commissioning Checklist at the rear of
this publication.
IMPORTANT:
During routine servicing, and after any
maintenance or change of part of the combustion circuit, the
following must be checked:-
• The integrity of the complete flue system and the flue seals.
• The integrity of the boiler combustion circuit and relevant
seals as described in Section 14.2.
• The operational gas inlet pressure as described in Section
12.2.1 to 12.2.3 and the gas rate as described in 12.2.4.
• The combustion performance as described in ‘Check the
Combustion Performance’
(14.1.4 to 14.1.6 below).
3. Competence to carry out Checking Combustion
Performance
B.S. 6798 ‘Specification for Installation & Maintenance of Gas
Fired Boilers not exceeding 70kW’ advises that:-
• The person carrying out a combustion measurement should
have been assessed as competent in the use of a flue gas
analyser and the interpretation of the results.
• The flue gas analyser used should be one meeting the
requirements of BS7927 or BS-EN50379-3 and be calibrated
in accordance with the analyser manufacturers’ requirements.
• Competence can be demonstrated by satisfactory
completion of the CPA1 ACS assessment, which covers the
use of electronic portable combustion gas analysers in
accordance with BS 7967, Parts 1 to 4.
Check the Combustion Performance (CO/CO
2
ratio)
4. Set the boiler to operate at maximum rate as described in
Section 12.2.
5. Remove the cap from the flue sampling point, insert the
analyser probe and obtain the CO/CO
2
ratio.
This must be
less than 0.004
.
6. If the combustion 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 ‘Annual Servicing - Inspection’ (Section 14.2) &
re-check.
• Replace the gas valve (Section 15.8) & re-check.