Water Treatment; Filling The Appliance And Adding Inhibitor - Bosch Worcester 2000 Series Installation And Maintenance Instructions Manual

6.2

Water treatment

Primary system flushing (Central Heating)
Ensure that the system has been cleaned:
• Following the guidance of BS 7593:
– Code of Practice for treatment of water in hot water central
heating systems.
• Overview available in Pre-installation, Cleaning primary systems
section.
Inhibitor (Central Heating):
Add a suitable inhibitor that is compatible with aluminium (or combined
inhibitor/anti-freeze, if the system is exposed to freezing conditions), to
the heating system in accordance with the DWTA code of practice and
manufacturer's guidelines.
The pH value of the system water must be between 6.5 and 8 or the
appliance warranty will be invalidated.
The inhibitor or combined inhibitor/anti-freeze must not cause damage
to the materials within the appliance (aluminium, mild steel, stainless
steel, copper and brass) and any other materials/components within the
system.
▶ Record the date when the inhibitor was added to the system on the
guarantee card.
▶ The concentration level of inhibitor in the system should be checked
every 12 months or sooner if system content is lost.
NOTICE:
Sealing agents
Normally the addition of sealing agents to the system water is not
permitted as this can cause problems with deposits left in the heat
exchanger.
▶ In cases where all attempts to find a system micro leak have failed,
Worcester, Bosch Group supports the use of Fernox F4 leak sealer.
Worcester 2000 – 6 721 814 551 (2019/09)
6.2.1

Filling the appliance and adding Inhibitor

Before pressurising the system.
The appliance integral expansion vessel is pre-charged to 0.75 bar
(equal to a static head of 7.5m (24.6ft)). A Schrader type valve is fitted
to the expansion vessel to allow for pressure adjustment if required.
▶ If an extra expansion vessel is fitted to the central heating system,
ensure that it is set to the same pressure as the appliance internal
expansion vessel, refer to separate instructions supplied with the
extra expansion vessel.
Filling the system - Sealed systems
NOTICE:
▶ Salt based softened water must not be used to fill the central heating
system.
▶ Check drain cocks and manual air vents are closed and all radiator
valves are open. Add a suitable inhibitor or combined inhibitor/anti-
freeze, if the system is exposed to freezing conditions, to the heating
system water in accordance with the manufacturers instructions.
▶ Turn on the water main and open the system valves.
▶ Fill the system to between 1 and 1.5 bar via a WRAS approved filling
loop or one of the filling link accessories.
– Refer to filling link accessory instructions for operation and use.
▶ The Automatic Air Vent will release any air trapped in the appliance.
▶ Manually vent all radiators, tighten when completed and check the
system for any leaks and correct if required.
▶ Top up the system pressure if the pressure drops below 1 bar.
▶ Isolate and remove filling loop connections to the system.
– Refer to Integrated filling link accessory instructions for any
further actions required after filling the system.
An optional filling link is available as an accessory. This can be used to fill
the system.
▶ Refer to Scope of delivery to check if an filling link is supplied with the
appliance.
Keyless filling link
▶ An additional 0.75bar static mains pressure is required above
required system pressure to ensure the effective operation of the
keyless filling link accessory.
Adjusting the operating pressure of the heating system
Display on the pressure gauge
1 bar Minimum charge pressure (when system is cold)
1 - 1.5 bar Optimal charge pressure
3 bar Maximum charge pressure at maximum heating
water temperature must not be exceeded (pressure
relief valve opens).
Table 18
If the indicator is below 1 bar when the system is cold:
▶ Top up the water until the indicator is between 1 bar and 1.5 bar
again.
If pressure is not being maintained:
▶ Check tightness of expansion vessel and heating system.
Commissioning
37