9
In more practical way, just using the nominal heat output of boiler (Qk) in terms of kW, the volume of
expansion tank can be calculated as;
Vg= 2,15.Q
k
(in litres)
Size of the safety line for delivery (in mm)
Size of the safety line for return
where Q
k
is the boiler output in kW.
5.4. Additional safety against over-heating
To ensure safety against high temperatures on boiler and heating system, a cooling loop (safety heat
exchanger) with activating valve must be installed. Safety heat exchanger includes the following items:
1. Safety heat exchanger (copper serpentine integrated with outlet stub pipe)
2. Safety valve
3. Auxiliary fittings / flexible hose
If the boiler water temperature exceeds 95
o
C, thermostat of the safety valve lets cold sanitary water flows
through the serpentine of the safety heat exchanger. Serpentine with cold water circulating inside cools
down the boiler water temperature. When the boiler temperature decreases below the safe degree, safety
valve shuts the cold sanitary water circulation, and the boiler goes back to normal operation.
NOTICE
The valves on the sanitary connections of safety heat exchanger must always be kept open.
Boiler can only be used with original safety heat exchanger kit which is tested and approved for
each boiler model. The safety valve could be purchased separately if it is not included in the kit.
Cold water must never be delivered directly to boiler inlet in order to solve overheating problems as
this will result in serious damage on boiler body. That application will end the warranty of the boiler.
k
SV
Q
d
.
5
,
1
15
k
SR
Q
d
15
