13
2.8
CHARACTERISTICS OF FEEDWATER
Where the mains water has a hardness of more than 20
- 25° Fr, the feedwater must be suitably softened both
for the hot water circuit and for the central heating cir-
cuit, so as to prevent formation of boiler scale due to
lime deposits, since this could lead to a reduced heat
exchange.
It should be remembered that even small encrustations
of just a few millimetres thick, on account of their low
thermal conductivity, cause a considerable overheating
of the walls of the boiler with serious consequences.
IT IS ABSOLUTELY ESSENTIAL THAT THE WATER USED
FOR THE CENTRAL HEATING SYSTEM SHOULD BE
TREATED IN THE FOLLOWING CASES:
– very extensive system (with high contents of feedwa-
ter)
– frequent addition of makeup water into the system.
Should it be necessary to empty the system either par-
tially or totally, the subsequent refilling should be carried
out using suitably treated water.
2.9
WATER FAILURE SAFETY DEVICE
The boiler is equipped with a water pressure switch set at
0.6 bar (1, Figs. 3 - 3/a), which goes into action, blocking
boiler operation, whenever the pressure inside the boiler
is less than the calibration value.
When the pressure switch trips, a red warning lamp lights
up (7, Fig. 18).
To restore burner operation, turn the charge cock and
bring the pressure back to between 1 and 1.2 bar.
2.10
SYSTEM FILLING
Filling of the boiler and the system is done by opening the
ball cock located on the underside of the boiler (Fig. 16)
and the charge cock located on the fixing jig in the
“20 R
CE IONO”
version. The charge pressure, with the system
cold, must be between 1 and 1.2 bar. During system filling
you are recommended to keep the main switch turned
OFF. Filling must be done slowly so as to allow any air
bubbles to be bled off through the air valves.
Should system pressure drop during operation, as a result
KEY
1 Separate-pipes kit
2 90° elbow MF with intake
3 Extension ø 80
4 Int.-est. ring kit
5 Intake terminal
6 Locking junction
7 Doubler fitting
8 Tile with articulated joint
9 Roof outlet terminal ø 80
10 45° elbow MF
11 90° elbow MF
12 Extension ø 80 with intake
13 Condensation outlet ø 80
Fig. 17 bis
