Checking The Expansion Vessel And System Pressure - Viessmann VITOPLEX 200 Instructions Manual

Commissioning, inspection, maintenance
Checking the function of the safety equipment
Check safety valves, water level and pressure limiter in
accordance with manufacturer's details.
Checking the function of the pressure switch
Installation instructions in the "pressure switch
set"
Checking the temperature controller setting if a building management system
is used (DCC system)
!
Please note
Shutting down from full load can result in high
material stress and material damage.
If a system with a higher ranking building man-
agement system takes over the temperature
control of the boiler, adjust the settings at the
temperature controller TR. Set the electronic
temperature controller to at least 10 K below the
mechanical temperature controller.

Checking the expansion vessel and system pressure

Expansion vessel manufacturer's documentation
Expansion vessel
1. Drain the system until the pressure gauge shows
"0". Alternatively: close the cap valve on the
expansion vessel and reduce the pressure in the
expansion vessel.
Note
The pre-charge pressure of the expansion vessel
(p ) is made up of the static system pressure (p
0
(= static head) and a supplement: p
plement.
The supplement depends on the high limit safety
cut-out setting. The following applies:
100 °C: 0.2 bar (0.02 MPa)
■
110 °C: 0.7 bar (0.07 MPa).
■
Pump controlled pressure maintaining systems
In heating systems with automatic pressure maintain-
ing systems also provide individual protection by instal-
ling an expansion vessel for each boiler. This applies
in particular to pump controlled systems with integral
deaeration.
See chapter "Water quality requirements".
*1
14
Note
Check when system is cold.
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 (0.01 to 0.02 MPa) higher.
The static pressure corresponds to the static head.
3. Top up with softened water
)
sure of the cooled system is 0.1 to 0.2 bar (0.01 to
St
0.02 MPa) higher than the pre-charge pressure of
= p + sup-
0 St
the expansion vessel.
Permiss. operating pressure: 6 bar (0.6 MPa)
Boiler output
Expansion
vessel
*1 until the charge pres-
kW Up to 1000
l 140
Up to 2100
300