Commissioning
47
Greenstar 4000 – 6 720 891 162 (2020/09)
6.8
CO and combustion check
The following combustion and flue integrity checks are mandatory and
these values must be recorded on the Benchmark checklist, at the end of
these instructions.
Once the gas rate and pressure have been confirmed as acceptable then
the CO and combustion checks can be undertaken.
The flow chart is given for guidance, the details of the checks are given in
the following sections:
• Checking flue integrity, (
6.9 "Checking flue integrity")
• Flue gas analysis, (
NOTICE
Before CO and combustion checks:
▶ Verify the appliance is connected to the correct gas type.
▶ Ensure the appliance is supplied with the correct gas inlet pressure
and gas rate as specified previously in the Commissioning section.
▶ Visually check the integrity of the whole flue system and confirm that
all the components are correctly assembled, fixed and supported.
▶ The flue gas analyser must be the correct type as specified in BS
7967. Before use the analyser must have been calibrated as
specified by the manufacturer. The installer must be competent in the
use of the analyser.
▶ Check and zero the analyser in fresh air as specified by the
manufacturer.
▶ The air/gas ratio valve is factory set and must not be adjusted during
commissioning unless this action is recommended following contact
with the Worcester, Bosch Group help line 0330 123 3366.
Fig. 67 Commissioning checks flow chart
Yes
No
Yes
Yes
Set boiler to
minimum rate.
Check all seals around the
burner, internal flue seals,
and case seals.
Rectify where necessary.
Turn off boiler and
call Worcester, Bosch
Group help line.
0330 123 3366
No
Boiler is operating
satisfactorily.
No further action
is required.
No
No
Verify flue integrity
O
2
≥ 20.6%
OR
CO
2
< 0.2%
O
2
≥ 20.6%
OR
CO
2
< 0.2%
No
Yes
Check CO and
combustion ratio
at maximum rate
Check CO and combustion
ratio at minimum rate
CO < 350ppm
CO/CO
2
ratio
< 0.004
CO < 350ppm
CO/CO
2
ratio
< 0.004
CO < 350ppm
CO/CO
2
ratio
< 0.004
Flue integrity test
using analyser
Yes
Set boiler to
maximum rate.
START
HERE
0010023581-002
Zero the analyser
in fresh air.
See notice above
Record values.
Do not adjust
the gas valve.
≥
= greater than
or equal to
<
= less than
