26
3.5. Planned shutdown of the boiler
After the fuel burns out, open all doors and maximally open the damper in
the smoke conduit. Remove ash, clean the boiler. Do not drain the circulating
water. Cool down time is equal to the ignition time.
3.6. Emergency Shutdown of the Boiler
In emergencies, such as when the temperature of 100
O
C is exceeded, if
component breaks down, if water charge is lost, if control & automatic
equipment or protection equipment fails or if pressure increases suddenly, it is
necessary to:
remove the fuel from the grate and move it outside the boiler room,
reduce the circulating water temperature by adding cold water to
the water charge, like during filling
maximally open the breeching throttle (if installed).
In case of boilers operating in closed systems, an emergency condition
may be any condition resulting from power outage (pumps stop) or from leaving
doors of the boiler open. The central-heating installation shall be protected by a
safety valve set to 2 bars, additionally the manufacturer shall protect the boiler
by a safety valve preset to 2.5 bar, however in case of an emergency condition,
such protections are insufficient. The boiler must be additionally protected with
a thermal protection valve, which will remove hot water from the boiler in case
of an emergency condition, while at the same time supplementing caused water
shortage with cold water from water pipe installation in order to cool down the
boiler and to reduce the pressure (section 2.5).
Please keep in mind that emergency conditions are likely to occur during
summer, when only household hot water is heated in the boiler. To prepare for
such conditions, it is worth to consider installation of a heat accumulator capable
of taking over the heating power surplus unavoidable in such circumstances.
Glowing fuel must not be extinguished or cooled down with water.
