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STZM@ ed 05/04 ZEUS Maior @
Technical Documentation
Technical Documentation
Gas settings.
Maximum and minimum gas pressure settings are done by
means of the gas valve, observing the values shown in the tables
for the corresponding gas type (see technical data).
A differential pressure gauge is used for reading the pressure: its
positive pressure point is connected to the gas valve (4) outlet
and to the positive pressure point at the top of the airtight
chamber (see figure).
Gas valve SIT 845.
Setting maximum pressure.
Draw some domestic hot water after having put the tempera-
ture selector on maximum.
Turn the brass nut (3) clockwise to increase pressure to the
burner and in the opposite direction to reduce it.
Setting minimum pressure.
(to be done after setting maximum pressure).
After turning power off to the modulating coil, turn the screw
(2) clockwise to increase pressure to the burner and in the op-
posite direction to reduce it.
Converting the gas type.
ere are special kits for adapting to a type of gas different
to the standard one the boilers are intended for (natural gas
or LPG).
Conversion consists in changing the burner nozzles and moving
the “NATURAL GAS-LPG” jumper (S1) on the modulating
board.
Maximum and minimum d.h.w. pressures are then set on the
gas valve in the way described above.
Maximum and minimum output in the central heating mode
and burner ignition pressure (see the table below) are set by way
of the relative trimmers mounted on the modulating board (see
modulating board operation).
Soft ignition values mm H
2
O
Natural gas LPG
ZEUS 21 Maior @ 25 70
ZEUS 24 Maior @ 25 65
Legend:
1 - Coil
2 - Minimum output adjustment screw
3 - Maximum output adjustment screw
4 - Gas valve outlet pressure point
5 - Gas valve inlet pressure point
6 - Protection cap
SIT 845 valve
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