Commissioning; Pre-Commissioning Checks; Filling The System; Water Treatment - Worcester 27i System Compact Installation, Commissioning And Servicing Instructions

NOTICE:
▶ External diverter valve(s) and all other 230V parts are
not supplied with the boiler.
▶ Refer to the manufacturer's instructions when
connecting external parts to the wiring centre.
▶ Worcester, Bosch Group cannot be held responsible
for wiring errors.
▶ A fascia mounted digital programmer/timer cannot be
fitted unless the optional integral diverter valve is
installed.
▶ There is an option to fit an internal diverter valve. This
also requires fitting an extra connector and a code
plug change.
See "Optional Diverter Valve". Mechanical and wiring
instructions supplied with integral diverter valve kit.
▶ Optional Integral Diverter Valve kit:
27kW - 7 716 192 758
30kW - 7 716 192 759
OPTIONAL EXTERNAL FROST STAT CONNECTION FOR PROTECTION
OF SYSTEM PIPEWORK IN UNHEATED AIR SPACE
Frost Thermostat
Pipe Thermostat
Wiring to Part L
zoned controls
FR FS LR LR
Fig. 55 Frost Thermostat
▶ Connect frost thermostat cables to terminals F
▶ These connections are not polarity sensitive.
▶ The external frost thermostat operates the pump, and may start the
burner.
5

COMMISSIONING

5.1

PRE-COMMISSIONING CHECKS

CAUTION: MAINS SUPPLY
▶ Isolate the mains electricity supply before starting
any work and observe all relevant safety precautions.
Check that the service and water pipes are connected to the correct
positions on the manifold.
Ensure that the washers have been fitted to the water connections and
the bonded washer to the gas connection on the manifold, refer to
Fig. 27.
1. - CH Flow (22mm)
2. - Gas inlet (22mm)
3. - CH Return (22mm)
▶ Check the gas type specified on the data label, on the right hand side
of the combustion chamber, matches that of the gas supply.
▶ Turn on the main gas supply, carry out a tightness test on the gas
pipework and connections with the boiler gas isolating pipe valve
open. Rectify any leaks.
▶ Check that the condensate pipe has been connected and correctly
fitted to the siphon.
Greenstar i System Compact - 6 720 807 726 (2013/05)
230V
MAINS
SUPPLY
E L N
230V 230V
OUT IN
N L N L N L N L N L
& F .
S R
▶ Check pressure relief drain pipe is correctly fitted and securely hand
tightened.
NOTICE: If the boiler is not to be commissioned
immediately then, after successfully completing all of
the checks and any rectification work:
▶ Close the gas valve
▶ Close the water shut off valve
▶ Isolate the gas supply
▶ Isolate the electricity supply
▶ Label appropriately
5.2

FILLING THE SYSTEM

1. Turn on the water main and open the system valves.
2. Open all radiator valves.
3. Fill the system via a WRAS approved filling loop to 1 bar then turn
close the filling loop valve.
4. The Automatic Air Vent will release any air trapped in the boiler.
5. Manually vent all radiators, tighten when completed and check the
system and correct any leaks.
▶ The boiler integral expansion vessel is pre-charged to 0.75 bar (equal
to a static head of 7.5m (22ft). A Schraeder 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 return,
adjust this to the same pressure as the appliance's internal expansion
vessel, refer to separate instructions with the extra expansion vessel.
6. If required increase system pressure back to 1 bar.
7. Isolate and remove filling loop connection to system.
5.3

WATER TREATMENT

NOTICE:
▶ Artificially softened water must not be used to fill the
central heating system.
ENSURE THAT THE SYSTEM HAS BEEN CLEANED.
REFER TO SECTION 3.1 OF THESE INSTRUCTIONS.
FLUSHING (Central Heating):
▶ Ensure the boiler is switched off.
▶ Open all drain cocks and drain the system while the boiler is hot.
▶ Close drain cocks and add a suitable flushing agent at the correct
strength for the system condition in accordance with the
manufacturer's instructions.
▶ Run the boiler/system at normal operating temperature for the time
stated by the manufacturer of the flushing agent.
▶ Drain and thoroughly flush the system to remove the flushing agent
and debris.
INHIBITOR (Central Heating):
▶ Check the drain cocks are closed and all the radiator valves are open
before adding a suitable inhibitor compatible with aluminium (or
combined inhibitor/anti-freeze if the system is exposed to freezing
conditions) to the heating system water in accordance with the
manufacturers instructions.
The pH value of the system water must be less than 8 or
the appliance guarantee will be invalidated.
▶ Fill the system via a WRAS approved filling loop to between 1 and 1.5
bar.
▶ Vent all the radiators; tighten vents when complete.
▶ Re-pressurise if necessary to 1bar.
▶ Set all controls to maximum.
▶ Record the date when the inhibitor was added to the system on the
Benchmark checklist.
COMMISSIONING
31