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 Installation And Service Instructions Manual

Commissioning, inspection, maintenance
Checking the neutralising system (if installed)
Checking the diaphragm expansion vessel and system pressure
Note
Check the diaphragm expansion vessel when the sys-
tem is cold.
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 diaphragm expansion vessel pre-charge pres-
sure is lower than the static system pressure: top
up with nitrogen until the pre-charge pressure is 0.1
to 0.2 bar (10 to 20 kPa) higher than the static pres-
sure.
Checking the function of the 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 120.
Note
To prevent operating faults and damage, operate the
appliance with uncontaminated combustion air.
CO content
■ The CO content must be < 1000 ppm for all gas
types.
38
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.
nitrides, sulphides) can cause material damage.
Remove leak detection agent residues after testing.
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 33.
Note
During commissioning, the combustion controller car-
ries out an automatic calibration. Only measure the
emissions approx. 30 s after the burner has started.
content must be between