Discharge Of Combustion Products (Fig. 6); Hydraulic Connections; Supply Water; Central Heating Outlet/Return Pipes - Ferroli TP3 LN Series Instruction For Use, Installation And Assembly

5.4 Discharge of the products of combustion (Fig. 6)
The flue and the flue fitting must be made in compliance with the standards and the
legislation in force, using rigid pipes that are resistant to high temperatures, conden-
sate and mechanical stress, and are airtight.
The flue must ensure the minimum negative pressure specified by the standards in
force, considering "zero" pressure at the fitting to the flue. Unsuitable or incorrectly
sized flues may increase the noise produced due to combustion, generate problems
involving condensation and negatively affect the combustion parameters.
Non-insulated flues are a source of potential danger. The joint seals should be made
using materials that can resist temperatures of at least 250°C. Suitable points for me-
asuring the flue gas temperature and analysing the products of combustion must be
prepared in the connection between the boiler and the flue. As regards the cross-sec-
tion and the height of the chimney, refer to the national and local standards in force.
WARNING: it may be possible formation of condensation inside the stack, because of
the low temperature of flue gases.
5.5 Water connections

5.5.1 Supply water

The chemical characteristics of the supply and top-up water are fundamental for
the correct operation and the safety of the boiler. The water should be treated using
suitable systems. The values shown in the table below can be used as references.
TOTAL HARDNESS ppm 10
ALKALINITY mg/l CaCO3 750
PH 8÷9
SILICA ppm 100
CHLORIDES ppm 3500
The water used in the central heating system must be treated in the following cases:
- Very large systems
- Very hard water
- Frequent introduction of water to top up the system.
If, in these cases, the system needs to be partially or completely emptied, it must be refilled with treated water. To control the volume of water
automatically refilled, an hour counter should be installed.
The most common phenomena that occur in heating systems are:
- Lime scale deposits
Lime scale tends to concentrate at the points where the temperature of the wall is higher. Due to their low heat conductivity, lime scale de-
posits cause a reduction in heat exchange to the extent that even when just a few millimetres thick, the heat exchange between the flue gas
and the water is limited, bringing an increase in the temperature of the parts exposed to the flame and consequently breakages (cracks) on
the tube plate.
- Corrosion on the water side
Corrosion of the metal surfaces on the water side of the boiler is due to the dissolution of iron into its ions. The presence of dissolved gases, in
particular oxygen and carbonic dioxide, play and important part in this process. Softened and/or demineralised water provides protection against
lime scale and other deposits, however does not protect against corrosion. The water therefore must be treated with corrosion inhibitors.

5.5.2 Central heating outlet/return pipes

The dimensions of the outlet and return pipes are shown for each model of the boiler, in the table of DIMENSIONS.
Check that the system features a sufficient number of vent openings. The boiler fittings must not be stressed by the weight of the connection
pipes to the system, and consequently special supports must be installed.
5.5.3 System fill/drain pipes
To fill and drain the boiler, a cock can be connected to fitting T4 at the rear (see the drawing of the DIMENSIONS).
36
EN
cod. 3545458/0 - 10/2019
TP3 LN
fig. 6