Commissioning; Cleaning The Primary Circuit; Flushing Kit Accessory; Filling And Venting The Unit - Bosch Worcester Greenstar HIU E Installation And Maintenance Instructions Manual

Commissioning

6 Commissioning
6.1

Cleaning the primary circuit

Ensure the pipe-work systems connected to the heat distribution unit
have been cleaned and flushed in accordance with the relevant
standards and regulations.
Refer to BSRIA guide BG29 for further guidance on water quality
requirements.
6.2

Flushing kit accessory

There is a flushing kit available as an accessory. This component
connects between the district/centralised heat source, external to the
appliance isolation valves. The benefit of this is that the primary circuit
can be flushed separately without the HIU being connected directly to
the primary circuit before the commissioning of the HIU.
To clean the newly installed pipe work between the appliance and the
district services pipe work.
▶ Ensure the appliance district isolation valves are in the closed
position to prevent any debris entering the HIU.
▶ Open the isolation valve on the flushing valve to flush the pipe work.
▶ Close the isolate valve once flushing is complete.
NOTICE: Reduced performance.
Flushing kit isolation valve left in the open position can
lead to poor network performance.
▶ Close the isolation valve upon completion of flushing
the primary circuit.
90°
Fig. 38 Flushing kit
6.3

Filling and venting the unit

Control valves
▶ In order to completely open the control valve, service
position can be used. This first calibrates the
valve and then after 10 seconds opens the valve for
10 minutes.
▶ Depending on the system configuration this can allow
higher than recommended flow temperatures if an
under-floor circuit if fitted.
30
6.3.1
▶ When opening the isolation valves take care not to induce any water
hammer.
▶ Open the district heating supply isolation valve.
▶ Open the district heating return isolation valve and release any air
using the manual air vent.
▶ Slowly open the isolation valve on the mains cold water inlet.
▶ Slowly open the isolation valve on the domestic hot water outlet.
▶ Venting district circuit (domestic hot water side): Provide a domestic
hot water demand in order for the domestic hot water control valve
to open, then any air can be vented out using the manual air vents at
the top of the plate heat exchanger.
▶ Open the central heating flow isolation valve
▶ Open the central heating return isolation valve
▶ Pull the lever [1] down to start the filling the central heating system.
▶ Monitor the pressure gauge needle [2].
▶ When the needle reaches between 1 to 1.5 bar on the gauge [3],
release the lever [1] to stop the filling process.
▶ Venting district circuit (central heating side): Provide a central
heating demand in order for the central heating control valve to open,
then any air can be vented out using the manual air vents at the top of
the plate heat exchanger.
90°
1
Fig. 39 Filling link operation
▶ Check the pressure and top up the central heating system if required.
▶ Repeat this process until there is no more air in the system and the
operating pressure remains stable at between 1 to 1.5 bar.
▶ When venting is complete:
– Ensure that all manual air vents are fully closed.
– Check for any leaks.
Fig. 40

Integral keyless filling link

District heating supply:
The maximum district heating system pressure is 10 bar.
▶ Ensure that the system pressure in the district
heating circuit does not drop below 1 bar as this may
effect system performance.
1.5 bar
3
1 bar
Min
2
Max
6720808917-43.1Wo
6 720 808 928 (2017/06)