EdilKamin LAGUNA W 25 Installation, Usage Et Maintenance page 59

CORRECT DIMENSIONING
ACCUMULATION
Installation of the boiler always includes con-
nection to the system of an inertial accumulator
(thermal fl ywheel), composed of an accumu-
lation tank, with thermal insulation where the
heated water circulates from the boiler.
This enables rapid absorption of increases or
decreases in temperature, increasing the au-
tonomy of the fully operational system.
In wood-burning boiler operation, the fuel can-
not be measured, therefore once loaded it must
be consumed in a single solution. When fully
operational, in modulation, the minimum power
supplied is greater than 30% of the nominal
thermal power, therefore you need to install
a correctly dimensioned inertial accumulator
according to the following formula pursuant to
Standard 303-5:
Vsp = 15 x TB x QN(1-0,3QH/Qmin) (in litres)
Where:
• Vsp is the accumulation volume in litres;
• QN is the nominal power of the boiler in kilo-
watts;
• TB is the combustion period in hours;
• QH is the average power required in kilowatts;
• Qmin is the minimum power of the boiler in
kilowatts.
Therefore assuming:
• QN boiler nominal power = 26.9 kW;
• TB combustion period = 3 hours;
• QH average power required = 20 kW;
• Qmin minimum boiler power 50% nominal =
13.5 kW.
Vsp = 670 litres
INSTALLATION
SAFETY HEAT EXCHANGER FOR CLOSED
CIRCULT OPERATION TO COMBINE WITH
THERMAL RELIEF VALVE
The boiler is equipped with a safety heat ex-
changer to connect to a thermal relief valve
which in the event of a power cut or circulator
blockage acts as a protection device on the
boiler to prevent overheating.
It is important to assemble the thermal relief
safety valve (Watts STS20 type) so that, in fully
operational mode, the safety heat exchanger is
connected to the main lines of the pressurised
mains water without any shut-off device on the
water supply (shutter, valves).
The discharge side must fl ow without obstruc-
tion in a gutter or drain.
The temperature of the cold water permitted
for the exchanger must be at least10±5°C with
maximum pressure of 1.5 bar.
Note: The thermal relief valve must be installed
before the system is loaded or operational.
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