Recirculation Pump; Adjusting The Door; For Models Prextherm Rsh 100N÷420N(Fig. 9); For Models Prextherm Rsh 500N÷950N (Fig. 10) - Ferroli PREXTHERM RSH 950N Instruction For Use, Installation And Assembly

PREXTHERM RSH N
The expansion pipe connects the expansion vessel to the system. This pipe will start at the T3 fitting (see the Dimensions table), and must not
be fitted with on-off valves. At fitting T3, or within 0.5 m of the first flange on the outlet pipe, install a safety valve suitable for the capacity of the
boiler and in compliance with current local standards. No type of shut-off device may be installed between the boiler and the safety valves, and
these valves should be set to operate when the maximum permitted operating pressure is exceeded.

5.5.5 Recirculation pump

Condensation ºof the water vapor contained in the flue gas leaving the boiler (conden-
sate) occurs when the return water temperature is below 50ºC. This is significant, par-
ticularly when the boiler is turned on in the morning after being off all night. Condensate
is acidic and corrosive, and will damage the metal plating on the boiler over time. It is
therefore advisable to install a recirculation pump with an anti-condensation feature, to
be fitted between the feed and return fittings, upstream of any mixing valve. While the
system is operating, the pump must ensure a flow-rate of 20 to 30% of the total. The
(anti-condensation) recirculation pump is controlled using the Low-Temperature Ther-
mostat Panel (optional). The bulb for the corresponding thermostat must be fitted at the
return (using a sheath that must be added by the installer of that pipe).

5.6 Adjusting the door

5.6.1 For models PREXTHERM RSH 100N÷420N(Fig. 9)
Opening
The burner door can be opened to the right or left. Simply loosen nuts 1 on the right or
left.
Horizontal tightness and adjustment
Rotate both lock nuts 2, tighten nuts 1 as needed, and lock both lock nuts 2.
Vertical positioning and adjustment
After assembling the burner, it may be necessary to reposition the door. To do so, loosen
nuts 1, loosen set screws 3, and adjust with nuts 4.
Tighten nuts 1 to completely flatten seal 5.
After installing the burner, the door must be positioned. This can be done by loosening
nuts 1 and 3 and set screw 5, and using nut 6 to adjust the height. This must be done so
that the entire rope seal presses against the plate, by tightening nuts 1 and 3.
5.6.2 For models PREXTHERM RSH 500N÷950N (Fig. 10)
On all pressurized boilers, it's possible to adjust and reverse the side where the door
opens.
Opening
To set the side of the door, simply tighten lock nuts 2 and 4 against nuts 1 and 3.
To reverse the side where the door opens, tighten lock nuts 2 and 4 on the opposite side.
Closing
Loosen lock nuts 2 and 4, tighten nuts 1 and 3 as needed, and retighten lock nuts 2 and
4.
Positioning
After installing the burner, the door must be positioned. This can be done by loosening
nuts 1 and 3 and set screw 5, and regular in height with the nut 6.
It will be necessary to do it in such a way that the whole closing cord presses on the
sheet, tightening the nuts 1 and 3.
cod. A73020821 - 2023-09
fig. 8
fig. 9
6
5
2
1
4
3
fig. 10
33
EN