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Alpha CD12S/20S/28S - Routine Servicing
7 ROUTINE SERVICING
To ensure efficient operation of the boiler it is recommended that it is checked and serviced as necessary at regular intervals.
The frequency of servicing will depend upon the particular installation conditions and usage, but in general once per year
should be adequate.
It is the law that any service work must be carried out by a competent person, i.e. Gas Safe registered personnel.
Warning:
Before servicing the boiler, isolate the electrical supply and close the boiler gas service cock. Allow the boiler to cool.
The data label is positioned on the inside of the left hand side panel.
Always test for gas tightness after servicing any gas carrying components.
Always carry out electrical system checks i.e. Earth Continuity, Resistance to Earth, Short Circuit and Polarity with a suitable
meter after servicing.
General
Please Note:
During routine servicing, and after any maintenance or change of part of the combustion circuit, the following
must be checked:
1. The integrity of the flue system and the flue seals, as described in Section 4.6 and 4.7.
2. The integrity of the boiler combustion circuit and relevant seals.
3. The operational (working) gas inlet pressure at maximum rate, as described in Section 5.5.3.
4. The combustion performance, as described in Section 7.
Competence to carry out the check of combustion performance
Please Note:
BS 6798:2009 Specification for installation and maintenance of gas-fired boilers of rated input not exceeding
70 kW net
advises that:
1. The person carrying out a combustion measurement should have been assessed as competent in the use of a
flue analyser and the interpretation of the results.
2. The flue gas analyser used should be one meeting the requirements of BS 7927 or BS-EN 50379-3 and be
calibrated in accordance with the analyser manufacturers' requirements, and
3. Competence can be demonstrated by satisfactory completion of the CPA1ACS assessment, which covers the use
of electronic portable combustion gas analysers in accordance with BS 7967, Parts 1 to 4.
Combustion check
Connect the flue gas analyser to the flue gas sampling point as shown in Fig. 29.
Notes: 1.
Prior to servicing, it is recommended that a flue gas analyser is used to measure the performance of the boiler
(refer to Fig. 28 for the position of the flue sampling point). If the CO/CO
2
ratio measured is greater than 0.003
or
when other checks and comments from the customer have indicated that there may be problems, cleaning of
the heat exchanger will be necessary. All Sections 7.1, 7.2, 7.3 and 7.4
must
be carried out. Repeat the flue gas
analyser test after reassembling the boiler and check that the CO/CO
2
ratio is less than 0.003.
If the CO/CO
2
ratio reading is still above, then you must repeat Sections 7.1, 7.2, 7.3 and 7.4 until you obtain a
ratio reading of below 0.003.
If the combustion reading is greater than the acceptable value AND the integrity of the complete flue
system and combustion circuit seals have been verified and the inlet gas pressure (and gas rate) have
been verified. Please call our Technical Helpline.
2.
If the CO/CO
2
ratio measured is less than 0.003 and other checks and comments from the customer suggest
there are no problems then only Section 7.1 and Section 7.2 paragraphs 1, 2 and 3 need to be carried out to
allow a visual check of the components within the room sealed chamber.
3.
If a flue gas analyser is not available, then all Sections 7.1, 7.2, 7.3 and 7.4
must
be carried out.
7.1 IMPORTANT NOTES PRIOR TO SERVICING
1. Check the flue terminal outside and ensure it is not blocked.
2. Run the boiler and check the operation of its controls.
3. Refer to Fig. 2 for location of flue sampling point.
4. Ensure that all system connections and fittings are sound. Remake any joints and check the tightness of any fittings that
may be leaking.
5. Refill, vent and re-pressurise the system as necessary. (Refer to Commissioning, Section 5.1).
If the system pressure exceeds 2.5 bar when operating at maximum temperature, the heating expansion vessel should
be checked and re-pressurised, if necessary.
Notes: 1.
Check the expansion vessel charge only when the system pressure is zero.
2.
The expansion vessel pressure test point is accessible from inside the boiler at the top.
6. Check that the condensate trap drain pipe is connected and all joints are sound.
7. Record details of the service in the Service Record in Section 12.
Содержание CD12S
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