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2. Main Factors affecting corrosion and System performance
• “PH” or relative Acidity/ Alkalinity are of key importance in managing the production of system corrosion. It is
recommended that PH Level of the system water be between 7 and 8.5 (ideally 7.4/7.5). A Lower PH level than
recommended would be classed as acidic and corrode all metals. Alternatively, too high a PH level would be
alkaline and will corrode aluminium components within the wetted part of the system.
• When considering a chemical treatment product to add to the system, we recommend products which incorporate a
mix for buffering, in order to control the PH level more effectively.
• Oxygen Ingress should be minimised by the use of closed systems and barrier pipe within the system design.
• Aggressive ions (such as flux residues) promote corrosion and, continue to do so unless neutralised or flushed out
completely. We would recommend a jointing approach that removes the need to use such compounds and adopt
the use of heat free systems.
• If traditional solder fittings are used then we would recommend the use of a recognised chemical treatment to flush
out and neutralise the system.
• The accumulation of sludge & debris can cause deposit corrosion which leads to pitting. We recommend the use
of a recognised chemical treatment to flush out and neutralise the system In addition, it is strongly advised to
contact the manufacturer of the chemical treatment to gain early involvement prior to treatment as to the correct
application and chemical to use.
3. Refurbishment and Improvement to existing systems
• It is vitally important that before commencing works on existing systems that a complete scan of the water quality
of the system be taken. If it is found that the system contains products of corrosion and/or PH levels in excess of
the required norms, it is recommended that the existing water is conditioned and treated to PRIOR to the work
commencing.
4. System commissioning (water quality) Water Treatment Chemicals
• We do not recommend the use of raw water for hydraulic testing due to the risk of corrosion of the water being left in
the system and potentially, the internals of the system being exposed to the air due to partial draining.
• Chemically dosed water should be in all filling in activities accordance with the chemical manufacturers’
recommendations and in accordance with BSRIA BG29 2012.
• After a suitable filling and flushing regime is used, relevant to the system material, all chemicals used to be suitable
for HIU must comply with EU norms DIN EN 12828 and current guidelines for heating systems. In addition, they
should also be non hazardous, non toxic and biodegradable.
• The use of correct cleaners and inhibitors is of primary, environmental concern. All chemicals used to treat the
system should not contain phosphates, sulphuric acid, nitrites. See BS7593:2006 Code of Practice for treatment of
water in domestic hot water central heating systems.
• Inhibitors should meet Buildcert as a minimum and preferably be recommended by the Energy Savings Trust (EST).
8. Appendix C
Summary of Contents for Meibes A1CX Series
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