Setting The Appliance To Maximum; Setting The Appliance To Minimum; Exiting Chimney Sweep Mode; Checking Gas Inlet Pressure - Worcester Greenstar 4000 Installation And Maintenance Instructions Manual

6.4.1

Setting the appliance to maximum

Maximum output mode
▶ A hot water outlet must be opened to prevent the appliance from
shutting down due to high temperature during testing.
▶ Press the ok key for 5 seconds until Chimney sweep is displayed.
▶ Confirm you have read and understood the alert message, press ok.
– The appliance enters chimney sweep mode and automatically
enters maximum output.
– The display shows the maximum percentage power (100%)
alternating with the flow temperature.
– The appliance will ramp up to maximum output in approximately
30 to 35 seconds.
6.4.2

Setting the appliance to minimum

Whilst the appliance is already in chimney sweep mode - maximum
output.
▶ Press the  button to set the appliance to minimum output.
– The display shows the minimum percentage of the power
alternating with the flow temperature.
– The appliance will take approximately 30 to 35 seconds to ramp
down to minimum output.
– Wait a further 30 seconds to allow the appliance to stabilise at
minimum output.
6.4.3

Exiting chimney sweep mode

To exit the chimney sweep mode:
▶ Press ok or d and the appliance will return to normal operation.
– If left in the chimney sweep mode the boiler will return to normal
operation after 15 minutes.
When exiting chimney sweep mode the pump will continue to run in
order to cool the heat exchanger. Boiler status code 208 will be visible
during this operation.
Greenstar 4000 – 6 720 891 162 (2020/09)
6.5

Checking gas inlet pressure

Measuring the inlet pressure
▶ Switch off the appliance and close the gas isolator.
▶ Unscrew the screw on the test nipple for the gas supply pressure and
connect a pressure gauge.
1
Fig. 64 Checking the gas supply pressure (above: SIT valve, below:
Honeywell valves)
[1] Gas valve - NG
[2] Gas valve - LPG
▶ Open the gas isolator and switch on the appliance.
▶ Ensure that there is heat transfer by opening the radiator valves and
any zone valves fitted.
Internal diverter valve: When running in maximum output in test mode,
and the water temperature is 74°C or less, the appliance will operate
both the central heating and DHW circuits with the internal diverter valve
in the mid position. It will be necessary to run sufficient water through
the DHW circuit to ensure that the appliance will not cycle on low heating
demands. This is to allow sufficient time for the setting procedure. When
the water temperature reaches 75°C the diverter valve will switch to CH
only and will only return to the mid position if the temperature is 65°C or
less.
External diverter valve/s: When the internal diverter valve is not fitted,
it is recommended to position the external diverter valve in the central
heating position.
▶ Set the appliance running at maximum output in chimney sweep
mode ( 6.4 "Chimney sweep mode").
▶ Check the required gas supply pressure according to following
section "Gas pressure within the system".
Commissioning
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