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Cleaning and treating an existing central heating system – Silver Clean

Procedure1. Identify and rectify mechanical faults.

2. Dump system water to a foul drain and refill with fresh plain water. Install a Fernox TF1 Total Filter or TF1 Compact.

3. Add Fernox Cleaner F3 or Cleaner F5 at the recommended dose through a radiator, the TF1 or filling loop.

4. Turn on the boiler and circulate the Cleaner F3 for a minimum of one hour.

5. Turn off the boiler and close the flow valve to the TF1. Remove the TF1 magnet and open the drain valve. Drain contents into a suitable container until the water runs clearer. Close the drain valve, open the flow valve and re-insert the TF1 magnet. Switch on the boiler.

6. Isolate all radiators by closing the wheel-head valves or TRVs except that furthest away from the boiler. Circulate the cleaner through the radiator for five minutes or until efficiency is restored. Check using a ‘touch test’. If the radiator remains cold at the bottom in the centre, rolling a Fernox MaxMag upwards from the bottom of the radiator can help to dislodge any persistent sludge in the base. Close the flow to the radiator.

7. Repeat step 5.

8. Repeat steps 6 and 7 for all radiators in the system.

9. Turn off the boiler, remove the magnet from the TF1 and open all radiators. Purge the system water to drain whilst at the same time introduce fresh water via the feed and expansion cistern or via the filling loop. Flush through until the water runs clear.

10. Isolate all radiators except that furthest away from the boiler, and continue to purge for five minutes.

11. Repeat step 10 on all radiators.

12. Use a Fernox TDS Meter to ensure that the total dissolved solids have been satisfactorily removed. The system can be regarded as being thoroughly flushed when the system water value is within 10% of the mains water. Differences over 10% mean that significant cleaner residues have been left in the system and further flushing is required.

13. Add Fernox Protector F1 500ml or Express at the recommended dose.

14. Refit the magnet assembly in the TF1 Filter.

15. The retreatment sticker provided with all Fernox Protectors should be correctly completed and applied to the boiler casing.

Note: For continual protection Fernox recommend Protector levels are checked annually (usually during the service) or sooner if the system content is drained down. This should be carried out using a Fernox Protector Test Kit.

If you are unsure of dose rates or require further advice, contact Fernox Technical Services on +44 (0)870 870 0362 or visit www.fernox.com

NB: Motorised valves should be manually opened during the flushing process and any anti-gravity valves should be by-passed or removed temporarily. If it is necessary to cap off the open vent during the mains flush to prevent overflow ensure the cap is removed prior to restarting the appliance.