Water Connections; Electrical Connections - Ferroli Prextherm N serie Installations, Bedienungs Und Wartungsanleitungen

2.1 Water connections

Make the water connections to the appliance according to the indications shown both next to each fitting and in Figure 5 of this booklet.
The connections must be made in such a way that the pipes are not under stress. The safety valve must be fitted in the central heating circuit,
as close as possible to the boiler, without there being any obstructions or on-off devices between the boiler and the valve.
The appliance is not supplied with an expansion vessel, and therefore such device must be connected by the installer. Please note that in this
regard, the pressure in the system, when cold, must be between 0.5 and 1 bar. Suitably treated water should be used in the central heating
system, to prevent any possible deposits in the boiler due to hard water, or corrosion due to aggressive water.
It should also be remembered that even minor deposits measuring just a few millimetres thick can cause, due to their low thermal conductivity,
significant overheating of the plate, with consequent serious problems: uniform and localised differential expansion that causes damage to the
plate and the welding.
2.2 Connecting the burner (fig. 3)
This appliance is designed for oil or gas jet burners. The burner must be chosen according to the field of operation, the operating pressure and
the size of the combustion chamber. The fuel flow-rate must in any case be set between the max. and min. heat input of the boiler.
A two-stage burner should be used, fitted with an intermediate flange for fastening the burner support plate ring 3 to the door 4. As regards the
dimensions of the draught tube, the lengths indicated in the table below should be followed, so as to avoid rapid flame reversal with a
consequent increase in the flue gas outlet temperature and a reduction in the efficiency of the boiler.
N.B. - To prevent the door from overheating near the burner support plate, close any cracks between the burner sleeve and the opening in the
door, using an insulating gasket 2. The fuel coupling hoses must be long enough to permit opening the door by 90° with the burner fitted.
Key
1 Flame inspection window
2 Insulating Gasket
3 Burner support plate
4 Front door
5 Turbulators é

2.3 Electrical connections

THE BOILER SHOULD BE CONNECTED TO A SINGLE-PHASE, 230 VOLT-50 HZ ELECTRICAL LINE, USING A PERMANENT CONNECTION,
INSTALLING A DOUBLE POLE SWITCH WITH CONTACT OPENINGS OF AT LEAST 3MM, AND SUITABLE FUSES. CONNECT THE
BURNER AND THE ROOM THERMOSTAT (IF FEATURED) AS SHOWN IN THE WIRING DIAGRAM IN CHAP. 4.
The electrical safety of the appliance is ensured only when the appliance is correctly connected to an effective earth system, as prescribed by
the safety standards in force. Have professionally qualified personnel check the efficiency and the rating of the earth system. The manufacturer
is not liable for any damage caused by the appliance not being correctly earthed. In addition, make sure that the electrical system is adequately
rated for the maximum power absorbed by the appliance, indicated on the rating plate, and in particular that the cross-section of the wires is
suitable for the power absorbed by the appliance.
4
4
1
3
2
min. 200
fig. 3
PREXTHERM N
5