De-scaling Instructions

De-scaling may have to be done periodically depending on the quality of the water you use. Scaling can appear as it does in a kettle if the water is a little hard. You may also have to do this (as I did) when buying a second-hand unit.
I found the cheapest place to buy citric acid powder was from a local home brewing store.

DE-SCALING

1. Heat up one liter of water to boiling temperature then let it cool down a bit (~200°F or 95°C).
2. Mix in one tablespoon of citric acid powder and stir well.
3. Pour the solution into the boiler. Do not turn the machine on before or during the de-scaling procedure.
4. Let the citric acid solution sit in the boiler for 30-60 minutes, then pour it out.
5. If not all of the scale has been removed, repeat steps 1-4.
6. Rinse out the boiler two or three times with warm water.
7. Add fresh water and turn the machine on. Flush out the steaming wand and the group.
   
8. (Note: never force the citric acid solution through the group head as this may damage the piston seals. If you think there is scale in the group head then you will have to dismantle it to clean it properly without damaging the seals.)
9. You are now ready to go!