Pipes, Expansion Vessel And Safety Valves; Recirculation Pump (Fig. 7); Opening And Adjusting The Front Door - Ferroli TP3 LN Series Instruction For Use, Installation And Assembly

TP3 LN
5.5.4 Expansion vessel and safety valve pipes
The TP3 LN boilers are suitable for operation with forced water circulation, both with open and closed expansion vessels.
An expansion vessel is always required, to allow for the increase in water volume due to heating.
In the first case, the height of the hydrostatic column must be at least 3 metres above the boiler casing and must have a sufficient capacity
to contain, between the surface of the water in the vessel and the overflow pipe, the increase in volume of all the water in the system.
High and narrow vessels are better, as they ensure minimum contact between the water surface and the air, thus reducing evaporation.
In the second case, the capacity of the closed expansion vessel must be calculated considering:
- the total volume of water contained in the system
- the maximum operating pressure of the system
- the maximum operating pressure of the expansion vessel
- the initial pre-charge pressure of the expansion vessel.
The expansion pipes connect the expansion vessel to the system. This pipes that run from fitting T3 (see the table of Dimensions), must
not be fitted with on-off valves. On fitting T3, or on the outlet pipe, within 0.5 metres from the first flange, install a safety valve sized for the
capacity of the boiler and in compliance with the local standards in force. No type of shut-off device may be installed between the boiler and
the expansion vessel, and between the boiler and the safety valves, while the valves should calibrated for activation at values no higher
than the maximum admissible operating pressure.
5.5.5 Recirculating pump (Fig. 7)
The condensation of the water vapour contained in the flue gas leaving the boiler (con-
densate) 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 con-
densate is acidic and corrosive 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 temperature 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 tempe-
rature for the purpose of controlling 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 TP3 LN models the door is hinged, fastened and reversed as regards the direction of opening as shown in Fig. 8. The following ope-
rations are required:
- The door is supplied with four equal brackets (pos. 3) and hinges.
- To establish the direction of opening, RIGHT or LEFT, unscrew the nut (pos. 7), unscrew and remove the R or L nut (pos. 6), depending
on which side the door opens from.
- Height adjustment of the door is performed using the nut (pos. 2); after having completed the adjustments tighten the dowels (pos. 1).
- Longitudinal adjustment is performed using the screw (pos. 8).
Key (Fig. 8)
1 Fastening dowel
2 Door support/adjustment nut
3 Hinge bracket
4 Hinge pin
5 Hinge screw
6 Hinge fastening nut
7 Fastening nut
8 Hinge bracket fastening/adjustment screws and nuts
cod. 3545458/0 - 10/2019
fig. 7
37
EN