4 Product information
4.7 Safety devices
Heat dissipation
–
This function of the boiler control is a safety device
that prevents overheating of the boiler.
–
Functioning: If the boiler temperature exceeds the
set
Heat dissipation maximum boiler temperature
(in the service menu -
General Settings
), all pumps
relating to the energy consumer units (e.g. heating
circuit, DHW tank, buffer tank, etc.) will be swit-
ched on and the heating circuit mixer opened. In
this way, energy is drained from the boiler and it
may be possible to prevent other safety devices
tripping.
–
If the boiler temperature falls below the set
Heat
dissipation maximum boiler temperature
minus
1°C again, the pumps and mixers will be operated
in standard mode again.
Overtemperature reset (OTR)
The safety temperature limiter (STL) is a safety device
that prevents overheating of the boiler.
Functioning: The STL stops the heating process at a
boiler temperature ~95°C (exclusively electrical func-
tion; fuel and air supply are interrupted).
After tripping, the STL must be manually released
again by unscrewing the black sealing cap
1
and pres-
sing the button as soon as the boiler temperature falls
below 60°C.
If the safety overtemperature reset trips, this is indi-
cated in the boiler control display.
Fig. 2-1: Position of the overtemperature reset
Thermal overload protection
–
The thermal overload protection prevents an uncon-
trolled increase in temperature and pressure inside
the boiler.
–
Functioning: At a boiler temperature > 95°C, the
valve opens and directs cold water through the
safety heat exchanger (which is placed in the
water jacket of the boiler). This lowers the boiler
temperature.
Fig. 2-2: Schematic diagram
Safety valve (to protect against excess pres-
sure in the system)
–
The safety valve
1
is a safety device for protecting
against overpressure in the water circuit of the hea-
ting system.
–
Functioning: The valve opens when the system
pressure exceeds 3 bar. Water/steam are dischar-
ged into an open drain via a discharge line, which
avoids consequential damage to the heating sys-
tem. The valve is closed during normal operation.
–
For normative specification see EN 12828.
Fig. 2-3: Safety valve integrated into boiler safety group
6
Operation manual
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