17
2.3.3 - MAX ALLOWABLE WORKING
PRESSURE
The boiler max allowable working pres-
sure is 6 bar, while the min. one is 0,8
bar.
The boiler does not have any special
protection device against water lack,
2.3.4 - SAFETY PRESSURE RELIEF
VALVE (not supplied)
A safety valve dimensioned for the sys-
tem capacity and in compliance with
local regulations in force shall be installed
2.3.5 - GAS MAINS
Due to the presence of a min. gas pres-
sure switch, the gas main diameter shall
be calculated carefully. Even though the
since this function is carried out by the
safety thermostats of the modules with
timeliness. However, the installation of
a min. pressure switch as well as its elec-
tric connection are foreseen (1/4” con-
on the flow pipe (within 500 mm from the
boiler).
2.3.6 - HYDRAULIC COMPENSATOR
OR OPEN MANIFOLD
For the correct operation of the boiler,
the use of an hydraulic compensator is
advisable because it guarantees:
-
separation and gathering of circuit dirt
-
best air venting
-
hydraulic de-coupling of the two
hydraulic circulation circuits.
nection on the return manifold and elec-
trical in series connection on the min.
gas pressure switch terminals).
gas valves have their own filter,
UNICAL suggests one further filter easy
to be checked, to be installed on the
gas pipe supply.
fig. 7
BOILER
CIRCUIT
HEATING
SYSTEM
CIRCUIT
D
1/2’’
KV
KR
HR
g
a
b
c
h
e
HV
1/2’’
1/2’’
1/2’’
g
C.H. FLOW
F
I
L
T
E
R
C.H. RETURN
C.H. FLOW
TABLE FOR THE RECOMMENDED
DIMENSION OF THE HYDRAULIC
COMPENSATOR
20.000
30.000
50.000
100.000
150.000
200.000
200
250
300
400
500
600
360 kW
360 - 450
450
Over
kW
- 540 - 630 kW
> 630 kW
100
125
150
200
250
300
100
125
150
200
250
300
200
200
250
250
300
300
1.000
1.000
1.000
1.500
1.500
1.800
300
300
300
300
400
400
150
150
150
200
300
300
1.650
1.650
1.700
2.250
2.500
2.800
200
200
200
200
200
200
