Giersch GIEGA NTG, Assembly, Installation And Maintenance Handbook

Page: 8 / 20

INSTRUCTIONS FOR THE USER
3.
APPLICATION
The boiler is designed to comply with the following European
Directives:
90/396 CEE –Directive concerning gas-fired appliances;
92/42 CEE –Directive concerning boiler efficiency;
73/23 CEE –Directive concerning low voltage appliances;
89/336 CEE –Directive concerning magnetic compatibility.
The boiler is designed only for the production of hot water up to
90°C used for heating purposes. The boiler can be integrated
with a hot water heater.
The features of the boiler and the serial number for identification
purposes are shown on the rating plate, which the installer must
fix onto the right hand side of the jacket.
(See Section «2 -GENERAL DESCRIPTION»).
4.
FUEL AND BURNER
(Fig. 1)
Diesel fuel with a max viscosity of 1.4°E at 20°C (NHV 10210
kCal/ kg) or natural gas (NHV 8570 kCal/Nm
3
) can be used. The
burners are the blown air type and must have a sleeve that is
slightly longer than the insulation thickness so that the head
projects as shown in figure 1.
The choice of burner depends on the capacity of the boiler and
the load losses on the flue gas exhaust side, as shown in the
table of specifications.
5.
PROPERTIES OF THE WATER
The chemical and physical properties of the water in the circuit
and top-up water are fundamental factors affecting safety of the
system and correct operation of the boiler.
Poor quality water is known to cause problems for the entire
system, the most serious and most frequent one being the
formation of scale on the heat exchanging surfaces.
Due to their low heat conductivity, even thin scale deposits
insulate the walls, which are not cooled by the circulating water
and cause irregular expansion or localised thermal shock.
So it is necessary to use suitable treated water if the hardness is
over 20-25 °F.
Water treatment is necessary when:
a) the installations are very large;
b) only very hard water is available;
c) for any reason the system has to be emptied partially or fully
and then needs to be filled again.
6.
CONTROL PANEL
(Fig. 2)
The pre-wired control panel comes with the
following:
•
ON-OFF switch (45);
•
Heating temperature regulation thermostat (44);
•
Safety thermostat with manual reset (46);
•
Heating water thermometer (49).
OPERATING PRINCIPLE
The burner produces the necessary calories depending on the
setting of the regulation thermostat (44) which keeps the water in
the heating circuit leaving the boiler at the set temperature. If
there is a room temperature thermostat connected to the boiler,
the burner lights when it receives simultaneous impulses from the
room temperature thermostat and the boiler regulation thermostat
(44).
7.
HOW TO OPERATE THE BOILER
(Figs. 2)
Starting up
•
Check the pressure on the gauge on the boiler (max 4 bar).
•
Open all the valves and/or gates in the heating and fuel
supply system.
•
Turn the switch (45) to position ON .
•
Set the boiler thermostat (44) to the required temperature and
the burner will start up.
•
Read the boiler water temperature on the thermometer (49).
•
Check operation of the circulation pump.
NOTE. The temperature of the water in the heating circuit can
be set from 50°C to 90°C. When the control is
activated, the pump starts up.
Switching off
•
Turn the boiler thermostat (44) fully anti-clockwise.
•
Allow the boiler to cool down to 50-60°C.
•
Turn the switch (45) to position OFF to power off the boiler.
Hot water system
•
The boiler can be connected to a heater for producing hot
water.
Emptying
•
If the boiler is not going to be used for a long time and the
temperature is low or anti-freeze has not been added, empty
the system via the cock (C -Fig. 3) which is accessible after
removing the front panel (33 -Fig. 18) of the jacket.
Overheating
•
If the boiler exceeds 100°C, the safety thermostat (46) turns
off the burner.
•
Unscrew the cap of the safety thermostat (46) and press the
reset button. If the inconvenience occurs again, call in a
qualified person to make the necessary repairs.