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Vitocrossal 300 CU3A 26 to 199 Service
5673 649 - 18
28
Service
Check CO
2
Setting
The Vitocrossal 300 CU3A boiler is equipped with
the Combustion Management System developed by
Viessmann which ensures optimal combustion quality
independent of gas quality and type. (For a description of
the Combustion Management System, see page 29 in this
manual). During initial start-up and maintenance you will
only need to check the CO
2
and O
2
content at the boiler
vent pipe.
Note:
The Vitocrossal 300 CU3A boiler comes factory
set to operation with natural gas. (For instructions
on how to convert to operation with liquid propane
gas, see page 17). For high-altitude operation above
5,000 ft. (1,500 m), see page 16. The MatriX burner
of this boiler is preset for the entire gas group. No
adjustment or readjustment of the burner is required.
1. Connect a flue gas analyzer to test port
A
at boiler
vent pipe adaptor.
2. Open gas shut-off valve, start up boiler and create
heat
demand.
3. Select higher/lower output
:
Service
menu
- Press OK and
simultaneously for approximately
4
seconds.
- “Actuator test”
- Select lower heating output: select “Base load OFF”.
Then “Base load ON” appears and the burner
operates at its upper heating output.
- Select upper heating output: select “Full load OFF”.
Then “Full load ON” appears and the burner
operates at its upper heating output.
- Terminate with OK or .
4. Measure
CO
2
and O
2
content at boiler vent pipe.
If the measured values deviated by more
than 1% from the ranges for the respective fuel
type listed in the right column or in the table on
page
29.
- check the venting system for leaks
(see subsection on page 20).
- check that the boiler is set for the gas type used
(see subsection on page 17).
CO
2
content range:
- 7.6 to 11.0% for natural gas
- 9.0 to 11.3% for LPG
O
2
content range:
- 3.8 to 7.3% for all gas types
5. Enter measured values into the Maintenance Record
on page 113.
6. Select the upper output: Select “Full load ON”.
Confirm with OK.
7. Measure
CO
2
and O
2
content at boiler vent pipe
adaptor. If the measured values deviated by more
than 1% from the ranges listed in the right column
or in the table on page 29.
- check the venting system for leaks
(see subsection on page 20).
- check that the boiler is set for the gas type used
(see subsection on page 17).
CO
2
content range:
- 7.6 to 11.0% for natural gas
- 9.0 to 11.3% for LPG
O
2
content range:
- 3.8 to 7.3% for all gas types
8. Press
OK
and after testing and enter measured
values into the Maintenance Record on page 113.