Checking The Neutralising System (If Installed) 26. Checking The Diaphragm Expansion Vessel And System Pressure; Checking Firm Seating Of Electrical Connections 29. Checking All Gas Equipment For Tightness At Operating Pressure; Checking Combustion Quality - Viessmann Vitodens 200-W Series Installation And Service Instructions Manual

Commissioning, inspection, maintenance
Checking the neutralising system (if installed)
Checking the diaphragm expansion vessel and system pressure
Note
Carry out this test on a cold system.
1. Drain the system or close the cap valve on the dia-
phragm expansion vessel and reduce the pressure
until the pressure gauge indicates "0".
2. If the pre-charge pressure of the diaphragm expan-
sion vessel is lower than the static system pres-
sure, top up with nitrogen until the pre-charge pres-
sure is 0.1 to 0.2 bar (10 to 20 kPa) higher.
Checking the function of safety valves
Checking firm seating of electrical connections
Checking all gas equipment for tightness at operating pressure
Danger
Escaping gas leads to a risk of explosion.
Check all gas equipment for tightness.

Checking combustion quality

The electronic combustion controller automatically
ensures optimum combustion quality. During commis-
sioning/maintenance, only the combustion values need
to be checked. For this, measure the CO content plus
the CO or O content. For a description of the elec-
2 2
tronic combustion controller functions, see page 102.
Note
Operate the appliance with uncontaminated combus-
tion air to prevent operating faults and damage.
CO content
The CO content must be < 1000 ppm for all gas
■
types.
34
3. Top up with water until the charge pressure of the
cooled system is 0.1 to 0.2 bar (10 to 20 kPa)
higher than the pre-charge pressure of the dia-
phragm expansion vessel.
Permiss. operating pressure: 4 bar (0.4 MPa)
Note
Only use suitable and approved leak detection agents
(EN 14291) and devices for the tightness test. Leak
detection agents with unsuitable constituents (e.g.
nitrites, sulphides) can cause material damage.
Remove residues of the leak detection agent after test-
ing.
CO or O content
2 2
The CO content must be within the following limits
■
2
(for upper and lower heating output respectively):
7.5 to 9.5 % for natural gas E and LL
–
8.8 to 11.1 % for LPG P
–
For all gas types, the O
■
2
4.0 and 7.6 %.
If the actual CO or O values lie outside their respec-
2 2
tive ranges, check the balanced flue system for tight-
ness, see page 29.
Note
During commissioning, the combustion controller car-
ries out an automatic calibration. Only test the emis-
sions approx. 30 s after the burner has started.
content must be between