Flue Gas Analysis; Checking The Flue Integrity; Cleaning The Siphon And Heat Exchanger; Cleaning The Heat Exchanger - Worcester Greenstar 2000 Installation And Maintenance Instructions Manual

9.6

Flue gas analysis

NOTICE
Combustion testing
▶ Combustion testing must be carried out by a competent person.
Testing must not be attempted unless the person carrying out the
combustion check is equipped with a calibrated flue gas analyser
conforming to BS 7967 and is competent in its use.
Flue gas analysis
▶ Ensure that the gas inlet pressure has been checked and is
satisfactory.
▶ Refit the test point plugs after the test has been completed.
▶ Set the appliance to maximum and minimum output in chimney
sweep mode ( 6.5 "Chimney sweep mode") for the flue gas
analysis checks.
▶ Check that the readings conform to those given in the following
tables. In addition to CO and CO/CO
maximum and minimum CO
2
Appliance combustion contents settings
CO Reading
2
Natural Gas - Maximum rated Output
Between 9.0 and 10.8%
Natural Gas - Minimum rated Output
A minimum of 0.6 lower than the maximum reading
taken but above 8.2%
1) Should be measured 10 minutes after firing the appliance
Table 33 CO settings
2
CO Reading
2
LPG - Maximum rated Output
Between 10.6 and 11.0%
LPG - Minimum rated Output
A minimum of 0.3 lower than the maximum reading
taken but above 10.2%
1) Should be measured 10 minutes after firing the appliance
Table 34 CO settings
2
If the CO is out of tolerance then please check:
2
▶ The gas inlet pressure.
▶ The gas rate.
▶ The fan test pressure.
▶ The flue and air intake, plus any possible blockages in the condensate
disposal.
▶ The condition of burner.
▶ For leaks or obstructions in the exhaust paths.
▶ That the injector is clean.
After all checks have been completed and the CO
then contact Worcester, Bosch Group helpline 0330 123 3366 before
making any adjustment to the gas valve.
Greenstar 2000 – 6 721 820 552 (2021/02)
ratio checks also check the
2
percentage reading.
CO Reading
1)
<250ppm
<250ppm
CO Reading
1)
<250ppm
<250ppm
is still out of tolerance
2
9.7

Checking the flue integrity

NOTICE
▶ Check flue joints are secure, the terminal and the terminal guard, if
fitted are clear and undamaged.
▶ Combustion testing must be carried out to BS 7967 by a competent
person. Testing must not be attempted unless the person carrying
out the combustion check is equipped with a calibrated Combustion
Analyser conforming to BS EN 50379 and is competent in its use.
Flue gas analysis
▶ Ensure that the gas inlet pressure has been checked and is
satisfactory.
▶ Refit the test point plugs after the test has been completed.
▶ Refer to chapter 6.10 "Checking flue integrity" and check that the
readings conform to those given, confirming flue system and
combustion circuit are ok.
9.8

Cleaning the siphon and heat exchanger

WARNING
Gaskets and seals - gas related components
▶ Burner/electrode assembly gasket must be replaced if disturbed.
▶ Other gaskets/seals must be checked and replaced where necessary.
▶ Do not attempt the cleaning procedure unless new gaskets and seals
are available.
9.8.1

Cleaning the heat exchanger

There is an optional tool available to assist in cleaning the heat
exchanger, part number 7 733 600 091.
Checking the electrodes and cleaning the heat exchanger
CAUTION
Risk of burns due to hot surfaces!
Individual components of the appliance can become very hot even after
being shut down for a long time.
▶ Allow the appliance to cool down before carrying out any work.
▶ If necessary, wear protective gloves.
WARNING
Material damage due to hot flue gas! - Gaskets and seals - gas related
components
Hot flue gas can leak through defective gaskets, damage the appliance
and endanger safe operation.
▶ Burner/electrode assembly gasket must be replaced if disturbed.
▶ Other gaskets/seals must be checked and replaced where necessary.
▶ Do not attempt the cleaning procedure unless new gaskets and seals
are available.
▶ Ensure that the gaskets are positioned correctly.
Inspection and maintenance
61