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Värmebaronen EP 350
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Expansion system - Safety pipe
The electric boiler must be connected to an expansion
system. The figures shown on this page are system prin-
ciples. The actual system must be installed according to
existing standards. Any additional equipment must be
installed as indicated by the manufacturer for its prod-
uct.
The air vent on the boiler's safety pipe must al-
ways be open. Otherwise, air collects in the top
of the boiler, which leads to disruption as the
float switch is triggered on account of insuffi-
cient water level.
Open system
The boiler’s safety pipe must be connected in an unisolata-
ble, uninterruptible rise to the expansion vessel, installed at
the highest point of the heating system.
The expansion vessel is dimensioned so that the volume
changes of the water, due to heating and cooling, are met.
Expansion vessels, safety pipes, aeration and overflow pipes
shall be installed in a manner that protects against freezing.
To avoid oxygenation of the water, the distance between the
highest point of the heating system and the expansion vessel
must not be less than 2.5 meters.
The pressure height must exceed the pump’s lowest static
pressure on the suction side.
To avoid damage in the event of any blockage
in the expansion system, the boiler should be
fitted with a safety valve.
Closed system, > 300 kW (max. 1 MW) < 105ºC
A boiler supplied with factory-fitted safety equipment meets
the requirements under EN 12828 for a closed system with-
out an expansion tank. Otherwise, the system must be supple-
mented with:
- Low pressure guard if there is a risk of the boiler boiling dry,
alternative to float switches.
Float switches are integrated in the boiler.
- Two temperature guards.
Integrated in the boiler.
- At least one safety valve, min. DN 15.
- Flow guard if the boiler does not tolerate zero flow.
From the point of view of safety, the boiler can cope with
zero flow.
- Valve for expansion tank, locked in open position.
- Two pressure guards, one with zero voltage release.
The boiler has integrated zero voltage release.
Exception:
- A boiler at a ‘higher level’ than consumers requires float
switches.
Safety valves are fitted with pressure guards and an automat-
ic vent valve on the boiler’s safety pipe. Valve for expansion
tank, must be locked in open position.
The opening pressure of the safety valve is
determined by the component in the system that
tolerates the lowest pressure.
The discharge pipe from a safety valve must meet the re-
quirements of EN 12828.
Steam or liquid that flows out of the safety valve when it
opens must be drained safely.
The discharge pipe from the safety valve is dimensioned so
that the blow-off capacity is not impeded.
The discharge pipe must be laid so it cannot freeze, must be
cleaned well and must be laid so that water pockets cannot
form.
There must be drainage, DN 10, from the safety valve dis-
charge pipe, if there is a risk that the water can remain
standing.
Pipe installation
