57
Checking the expansion vessel and process circuit pressure
Note
Carry out this test on a cold system.
C
B
A
Fig. 44
1.
Remove cap
B
from the expansion vessel.
Drain the process circuit until pressure gauge
C
indicates "0".
2.
Top up with nitrogen at connection
A
until the pre-
charge pressure is 1.7
±
0.25
bar (170
±
25
kPa).
3.
Fill the process circuit with suitable water and
purge; see page 41.
Operating pressure: 2.8 to 3.0 bar (0.28 to
0.3 MPa).
Note
■
Observe the safety valve tolerance of
±
10 %.
■
Take into account the increased volume and
pressure caused by heating of the fill water dur-
ing operation.
Checking the 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.
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.
Checking the 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 and
the CO
2
or O
2
content. For a description of the elec-
tronic combustion controller functions, see page 149.
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.
CO
2
or O
2
content
■
The CO
2
content must be within the following limits
for the lower and upper heating output respectively:
–
7.5 to 9.5 % for natural gas E and LL
–
8.8 to 11.1 % for LPG P
■
The O
2
content must be between 4.0 and 7.6 % for
all gas types.
Commissioning, inspection, maintenance
Checking the neutralising system (if installed)
5678 044 GB
Summary of Contents for D2RA
Page 113: ...113 Maintenance Checking the Vitotronic 200 H accessories cont 5678 044 GB Maintenance ...
Page 133: ...133 Parts lists Sorption module hydraulics cont 5678 044 GB Components ...
Page 136: ...136 0001 0002 0003 0004 0005 Fig 83 Parts lists Miscellaneous 5678 044 GB Components ...
Page 163: ...163 5678 044 GB ...
