Recirculating Pump; Opening And Adjusting The Front Door; Assembling The Burner; Connecting The Flame Inspection Window - Ferroli PREXTHERM RSW Notice Technique D'installation, D'utilisation Et D'entretien

5.5.5 Recirculating pump (Fig. 8)
The condensation of the water vapour contained
in the flue gas leaving the boiler (condensate)
occurs when the return water temperature is
less than 55°C and is significant above all when
starting in the morning, after the boiler has been
off all night. This condensate is acidic and corro-
sive and, over time, attacks the metal plate on
the boiler. Consequently, a recirculating pump
with the function of preventing condensate
should be installed between the outlet and
return fittings, upstream of any mixing valve.
The pump must ensure, when the system is
operating, a flow-rate of between 20 and 30% of
the total; it must also ensure a return water tem-
perature no less than 55°C, while the required
discharge head is quite low, as it only needs to
overcome the resistance of the boiler and the
valves. To measure the effective central heating
return inlet temperature for the purpose of con-
trolling the condensate prevention pump or
managing the functions for getting the system to
stable temperature operation, a probe socket
must be fitted at a distance equivalent to 3-5
times the diameter of the return pipe upstream
of the water coupling.

5.6 Opening and adjusting the front door

For the PREXTHERM RSW models 92÷1060,
the door is hinged, fastened and reversed as
shown in Fig. 9.
The following operations are required:
- The door is fitted with four equal hinges, the
pins (pos. 3) are inserted either on the right or
the left of the support (pos. 1).
For the direction of opening, remove the pins
on the right or the left, and then fasten the
door with the screws (pos. 6).
- Axial adjustments are possible by screwing in
or loosening the fastening nuts.
Key (Fig. 9)
1 Hinge support bracket
2 Hinge
3 Hinge pin
4 Fastening screw and nut
5 Bush
6 Closing bolt and washer
For PREXTHERM RSW models 1250÷3600,
the door is hinged, fastened and reversed as
shown in Fig. 10.
The following operations are required:
- Unscrew the nuts (pos. 8) on the side that
closes, and open the door.
- Tighten the nuts (pos. 8) again on the side
that closes, and close the door.
- Tighten the spare nuts (supplied with the boi-
ler accessories) in pos. 8, making sure they
are fully tightened.
- Unscrew the nuts (pos.7) corresponding to
the part that acts as a hinge.
- Open the door and unscrew the nuts (pos. 6).
- Close the door and use a pair of nuts (pos. 7).
Key (Fig. 10)
1 Fastening dowel
2 Hinge pin support nut
3 Hinge support ears
4 Hinge pin
5 Bolt welded to the pin
6 Bolt-door fastening nut
7 Bolt-door fastening nut
8 Bolt-door fastening nut
5.7 Assembling the burner (Fig. 11)
The assembly of the burner to the door of the
boiler must ensure perfect tightness to the pro-
ducts of combustion.
Once having installed the burner on the boiler,
the space between the burner draught tube and
the refractory material on the door must be filled
with the layer of ceramic fibre (A) supplied.
This prevents the door from overheating and
consequently from being irreversibly deformed.
The fuel connections to the burner must be loca-
ted so as to allow the complete opening of the
boiler door with the burner installed.
RSW L min. (mm) L max. (mm)
92-152 230
190-350 250
469-600 290
720-1060 320
1250-1480 320
1890 340
2360 340
3000-3600 350

5.8 Connecting the flame inspection window

(Fig. 12)
The flame inspection window features a pressu-
re fitting (1) to be connected via a silicone hose
or copper pipe to the outlet on the burner (2).
This operation allows the air blown by the fan to
cool the glass and prevent it from turning black.
Failure to connect the hose or pipe to the win-
dow may cause the glass to break.
5.9 Assembling the panels, models 92÷300
Sequence (Fig. 13)
a) Fasten the 2 supports (pos. 17) to the boiler
plates using the corresponding screws and nuts.
b) Position the bottom side panels (pos. 2 and
4), hooking them to the support (pos. 17).
To know which of the two sides is the right or
the left, refer to the hole for the cable gland
plate (pos. 9), which must be facing the front
of the boiler.
c) Position the top side panels (pos.1 and 3),
hooking them to the boiler supports.
d) Fasten the control panel to the top panel
(pos. 5).
e) Rest the top panel (pos. 5), complete with the
control panel, on the side panel (pos. 1),
complete with springs, closing pins and nuts
(pos. 14-15-16) .
f) Insert the bulbs of the instruments into the
sheaths, as shown in Fig. 13-20, and make
the electrical connection between the control
panel and the power line, burner and any
pumps etc. The probes should be inserted
fully into the corresponding sockets, to impro-
ve contact. Then secure the capillary tubes
with the springs. Close the cover on the elec-
- 18 -
trical panel, pass the burner plug through the
side plate (pos. 9) and secure the cable with
the cable gland supplied. Fasten the plates
(pos. 9) with the screws (pos. 10).
g) Fit the top panel (pos. 6) to the side panel
(pos. 3) complete with springs, closing pins
and nuts (pos. 14-15-16).
h) Fit the rear panel (pos. 8) to the boiler using
the screws (pos. 13) and the nuts (pos. 14).
i) Fit the front panel (pos. 7) to the front door using
the screws (pos. 11) and the nuts (pos. 12). The
panel must be fitted before installing the burner.
j) Fasten the rating label to the boiler, see
Chap. 1.4, after having cleaned and degrea-
sed the part in question using a suitable sol-
vent, and apply it so as to ensure perfect
adhesion. Do not remove the rating label, as
it will lose its adhesiveness.
The rating label is included in the document
envelope.
5.10 Assembling the panels, models 350÷1060
Sequence (Fig. 14)
S a) Fasten the 2 supports (pos. 24) to the boiler
300 172 plates using the corresponding screws and nuts.
320 192 b) Carefully position the bottom side panels
360 218 (pos. 3 and 4 - 7 and 8), hooking them to the
support (pos. 24). To know which of the two
390 239
390 248 sides is the right or the left, refer to the hole
410 262 for the cable gland plate (pos. 15), which
470 262 must be facing the front of the boiler.
480 272 c) Position the top side panels (pos. 1 - 2 and 5
- 6), hooking them to the boiler supports.
d) Fasten the control panel to the top front panel (pos. 9).
e) Rest the top panel (pos. 9), complete with the
control panel, on the side panel (pos. 1),
complete with springs, closing pins and nuts
(pos. 20-21-22).
f) Insert the bulbs of the instruments into the
sheaths, as shown in Fig. 14-21, and make
the electrical connection between the control
panel and the power line, burner and any
pumps etc. The probes should be inserted
fully into the corresponding sockets, to impro-
ve contact. Then secure the capillary tubes
with the springs. Close the cover on the elec-
trical panel, pass the burner plug through the
side plate (pos. 15) and secure the cable with
the cable gland supplied. Fasten the plates
(pos. 15) with the screws (pos. 16).
g) Fit the support (pos. 23)
h) Fit the top panels (pos. 11-12-10), hooking
them to the side panels (pos. 2-5-6) complete
with springs, closing pins and nuts (pos. 20-21-22).
i) Fit the rear panel (pos. 14) to the boiler using
the screws (pos. 19) and the nuts (pos. 25).
j) Fit the front panel (pos. 13) to the front door
using the screws (pos. 17) and the nuts
(pos. 18). The panel must be fitted before
installing the burner.
k) Fasten the rating label to the boiler, see
Chap. 1.4, after having cleaned and degrea-
sed the part in question using a suitable sol-
vent, and apply it so as to ensure perfect
adhesion. Do not remove the rating label, as
it will lose its adhesiveness.
The rating label is included in the document
envelope.