Cleaning The Sensor Well For Flue Gas Temperature Sensor; Checking The Expansion Vessel And System Pressure - Viessmann Vitoligno 200-S Installation And Service Instructions Manual

Cleaning the air box and secondary air supply
D
C
Fig. 31
1. Remove air box and replace self-adhesive gas-
A
ket B if required.
2. Remove sealing flange

Cleaning the sensor well for flue gas temperature sensor

A
Fig. 32

Checking the expansion vessel and system pressure

Note
The expansion vessel can lose some of its charge
pressure over time. When the boiler heats up, the
pressure gauge will indicate a higher pressure of 2 or
3 bar (0.2 or 0.3 MPa). The safety valve may also
respond and discharge the excess pressure.
Therefore check the expansion vessel pre-charge
pressure annually.
Check whether the installed expansion vessel is ade-
quate for the system water volume (GB only).
Carry out this test on a cold system.
.
C
Commissioning, inspection, maintenance
(cont.)
B
A
3. Replace packing cord
Remove and clean sensor well
Note
When replacing the flue gas temperature sensor, do
not remove the sensor well; only undo the cable fitting.
1. Drain the system until the pressure gauge shows
"0".
Alternatively, close the cap valve on the expansion
vessel and reduce the pressure until the pressure
gauge indicates "0".
2. If the pre-charge pressure of the expansion vessel
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 system
pressure.
.
D
.
A
43