geminox THI 10-35 SEP, Technical Instructions, Page: 15 / 34

- 15 -
MAINTENANCE
4 - EXPANSION VESSEL PRE-INFLATION PRESSURE CHECK
- Drop the pressure in the heating installation by
opening the drain cock or the safety valve (pres-
sure gauge reading under 0.5 bar).
- Check the pressure in the expansion vessel and
if necessary bring it back up to pressure, or repla-
ce it if the membrane is punctured (water present
in the inflating valve).
- To optimise the efficiency of the vessel:
• adjust its pre-inflation pressure in line with the
installation. It must correspond to the static hei-
ght of the installation (H) expressed in bars
(height between the highest point of the instal-
lation and the expansion vessel, with 10 me-
tres = 1 bar),
• adjust the filling pressure of the installation to a
value of over 0.2 bar above the pre-inflation
pressure of the vessel (after totally bleeding
the air from the installation).
5 - COMBUSTION PRODUCT CONDUITS (FLUE)
- Check the combustion product evacuation con-
duit and the air inlet conduit at least once a year
(airtightness of the parts that may be disassem-
bled - conduits not obstructed).
6 - DRAINING
- Cut the power supply,
- turn off the gas cock,
- turn off the heating flow/return valves (if they are
fitted),
- connect the drain valve (18) to the sewage sys-
tem,
- open the drain valve.
Ensure that the air bleed (16) is open, as
soon as the pressure gauge indicates a
zero pressure to allow air to enter the
boiler shell.
H
Water inlet
Dilated water
volume
Inflating
valve
Pressure rises
as the air is
compressed
Max vessel
volume
Membrane
AM
4
-0
6
-3
Fig. 9
!
TH
I-
9
8-
0
16
18
Fig. 10