Checking The Expansion Vessel And System Pressure; Servicing The Safety Valves And Checking Their Operation; Cleaning The Flue Pipe; Checking The Gaskets And Seals - Viessmann VITOLIGNO 300-C Installation And Service Instructions Manual

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.
1. Drain the system until the pressure gauge shows
"0".

Servicing the safety valves and checking their operation

Servicing thermally activated safety equipment
!
Please note
Faulty thermally activated safety equipment can
lead to injury and material damage.
Check and clean the filter at the coolant inlet.
■
Do not loosen or tighten the nut on the red
■
operating button on the safety valve.

Cleaning the flue pipe

Checking the gaskets and seals

Check the following gaskets and seals:
Boiler
■
Ash box cover
–
– Ash removal cover
– Profiled cover seal
– Gasket, connection piece, ash box
– Combustion chamber door
– Maintenance cover, grate
Heat exchanger cover
–
Packing cord of combustion chamber bricks
–
■ Charging
– Pellet hopper cover
– Pellet hopper maintenance cover

Checking the grate limit switch and end position

Danger
Risk of crushing and entanglement through the
grate
Do not reach in through the maintenance cov-
ers.
Commissioning, inspection, maintenance
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.
3. Top up with water until the charge pressure of the
cooled system is at least 1.0 bar (0.1 MPa), and is
0.1 to 0.2 bar (10 to 20 kPa) higher than the pre-
charge pressure of the expansion vessel.
Permiss. operating pressure: 3 bar (0.3 MPa)
Carry out a manual performance verification.
When pushed, the red button opens the safety valve
and releases the coolant.
The position switch and the end position of the grate
are checked visually. The grate must be horizontal in
its end position.
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