Vitosol 100-FM/200-FM Installation, Operating and Service
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5786 604 - 02
Set Expansion Tank Pre-charge Pressure
1. Cover the collectors with tarpaulin (if necessary).
2. If the system has already been filled, release fluid to
ensure the system fluid pressure gauge indicates 0 psi
(0 bar), or isolate the expansion tank from the system
using the service valves and reduce the fluid pressure
at the expansion tank connection. For new installations,
set tank pressure prior to filling the system.
3. Calculate the air cushion charge pressure of the
expansion tank using the formula on page 36.
4. In most cases the pre-charge pressure of the
diaphragm expansion tank is factory set at 44 psig
(3.0 bar) will be lower than the calculated charge
pressure. Top up with sufficient amount of nitrogen
through the air valve to raise the charge pressure to
equal the calculated value.
Legend
A
Heat transfer medium
B
Nitrogen filling
C
Nitrogen buffer
D
Safety water seal
E
Safety water seal under max. pressure
Factory set condition
[3 bar (44 psig) pressure]
Solar heating system
filled without heat effect
Under max. pressure at the
highest process medium temperature
IMPORTANT
Record the “pre-charge pressure level” on the expansion
tank for future reference.
Start-up
