Polyphosphate dosing unit: dosing device with polyphosphate beads able to prevent the formation of limescale in domestic hot water distribution systems.

In order to protect water and heating systems against limescale deposits and corrosion, it is possible to add specific chemicals (in particular polyphosphate salts) to drinking water. MyDOS polyphosphate dosing unit system supply a precise dosing and correct consumption of polyphosphate based on and in accordance with the water characteristics. Polyphosphate also performs a pipes protective function by exerting an anti-corrosive action. myDOS is a device designed and certified for the proportional dosing of chemical additives for the treatment of drinking water. myDOS container can resist to temperatures down to – 20 °C and contains polyphosphate beads certified for the treatment of up to 30 cu.m of water.

– container resistant to temperatures down to -20 °C
– in-line connection with swivel nut and 1/2″ F fittings
– precise and constant dosing
– treatment of up to 30 cu.m with one Mayline myREDOS certified refill
– max. capacity of 1.5 cu.m/h and max. operating pressure of 8 bar
– innovative design with optimised spaces
– easy and certified refill by inserting the bag with polyphosphate beads in the container
– no turbulence in the container.


Code | Package: MY/DOS | 10 pieces
MY/REDOS | 10 pieces (refill bags)
Important note: MYDOS is a product MADE IN ITALY with high-quality materials such as nickel-plated brass and high-strength polymer. The container (resistant to -20 °C) houses the polyphosphate beads refill bag, designed to treat up to 30 cu.m. of water and last approximately 6 months. The food-grade plastic bag containing the beads must not be removed (DO NOT OPEN the bag with the polyphosphate beads).
The polyphosphate beads comply with existing EC standards (EN 1208) and FAO/WHO regulations. The refills are also NSF certified according to NSF/ANSI Standard 60. MYDOS complies with the requirements of the Decree of the Italian Ministry of Health no. 174 of 6 April 2004, and is therefore suitable for use on drinking water.
Using refills with polyphosphate beads other than myREDOS original ones by Maychem will void the warranty.
Instructions for use: 1) Disconnect power to the boiler and close the upstream domestic cold water inlet by acting on the tap, open any domestic water tap and the domestic draining tap to allow the pressure in the domestic water circuit to be released.
2) Locate an appropriate position for dosing unit installation considering also the spaces required to remove the container for inserting the beads refill with the bag (DO NOT OPEN the bag with the polyphosphate beads).
3) Install and connect the dosing unit under the boiler on the cold water supply pipe for domestic hot water production.
4) Reopen the cold water inlet tap.
5) Open the needle valve: this will allow the water to flow down into the bowl and come into contact with the polyphosphate beads inside the bag. A special feature is the gradual release of the polyphosphate, ensuring a constant concentration.

myDOS - Technical datasheet