Checking The Expansion Vessel And The System Pressure - Viessmann VITOSOL-F Service Instructions Manual

Commissioning, inspection, maintenance
Further details regarding the individual steps
Note
The thermal insulation of external
pipes must be resistant to tempera-
ture and UV rays. The insulation must
be protected against attack from small
animals and birds (e.g. metal sheath),

Checking the expansion vessel and the system pressure

1. Drain the system. For this, close
the cap valve on the expansion
vessel (if installed) and reduce the
pressure.
2. If the pre-charge pressure of the
expansion vessel is lower than the
set value, top up with nitrogen until
the pre-charge pressure equals the
set value.
Static head (top edge of collector to
expansion vessel): ........... m
Set pre-charge pressure of the
expansion vessel:
0.7 bar + 0.1 x static head in m
0.7 bar + 0.1 x ......... m = ........ bar
8
(cont.)
3. Top-up heat transfer medium until
the system pressure is 0.3 to
0.5 bar higher than the set pre-
charge pressure of the expansion
vessel (create a safety water seal
in the expansion vessel).
The safety water seal should be
0.005 x liquid content of the com-
plete system, but no less than
3 litres.
Liquid content of the system = con-
tent of pipes + content of collectors
+ content of the indirect coil of the
DHW cylinder and safety water
seal for the expansion vessel.