Servicing 6; Routine Service; 6-1.1 Service Procedure - OSO Dualstream Technical Installation Manual

6-1 ROUTINE SERVICE

The OSO Dualstream system should have a routine service at least once in 12 months.
IMPORTANT: Always turn off the heating system and electricity supply to the OSO Dualstream before
working on the System.

6-1.1 Service Procedure

1. Turn the Heating System OFF.
2. Turn the electrical supply to the OSO Dualstream OFF.
3. Close the Stop Cock.
4. Open the hot taps.
5. Attach a hose to the Cylinder Drain Cock and empty the Cylinder.
6. Remove Immersion Heater, remove limescale and examine the element.
In hard water areas it is probably better to replace the Immersion Heater if heavily scaled.
7. Replace Immersion Heater 'O' Ring.
8. If heavy scaling is evident then descaling the system is recommended.
9. Clean and check the line strainer in the Pressure Reduction Valve - replace if required.
10. Check and clean the expansion relief valve - replace if required.
11. Flush the system if descaling has been carried out and refill the system.
12. Open the cold tap to empty the accumulator.
13. Check Accumulator pressure is 1-1.5Bar below the set pressure of pressure reducing valve.
14. Check the system for leaks including accumulator and around the Immersion Heater.
15. Test the operation of the Pressure and Temperature Relief Valve by turning the Cap to the left and ensure that
the water flows freely and safely to waste.
16. Test the operation of the Expansion Relief Valve by turning the Blue Cap to the left and ensure that the water
flows freely and safely to waste.
17. Check that no water is passing through the Expansion Relief Valve or the Pressure and Temperature Relief
Valves, this will be evident at the Tundish.
18. Switch on the heating system.
19. Check operation of Motorised Valve by setting heating system to call for hot water. The valve should open.
Then turn hot water off - the valve should close.
20. Wait for the system to heat up.
21. Check temperature of tap water.
22. Check operation of Cylinder Thermostat. When turned down below tank temperature the Motorised Valve
should close. When turned up above tank temperature the Motorised Valve should open.
23. Check for leaks again when the system is up to temperature.
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SERVICING 6