19
stress on all its elements during operation.
In cases where the total quantity of heating
water in the closed system exceeds 180 l it
is essential to include a second expansion
vessel in the system. This vessel must
have an identical same construction, i.e. it
must be closed, with a membrane.
The resultant value of the water pressure
in the system when cold is constantly
indicated by the red (adjustable) hand of
the boiler pressure gauge. If the pressure
drops beneath such an indicated value it is
necessary to seek and rectify any leakages
or to de-aerate the system more effectively
(or both). If pressure drops repeatedly and
the entire system is effectively sealed and
properly de-aerated, this most probably
represents a fault in the expansion vessel,
and it is essential to call an authorised
technician to rectify this fault.
Upon fi lling of the hot water tank it is
necessary to open the infl ow and outfl ow
from the tank and allow the water to fl ow
out until it is entirely clear and without air
bubbles.
Before fi nal assembly of the boiler it is
necessary to fl ush the distribution pipes
of the heating system several times with
pressurised water. In older, used systems
this must be performed against the fl ow
direction of the heating water.
Note:
It is recommended to mount a
sludge trap in front of the boiler (i.e. on
the piping with return heating water). The
construction of this trap should enable
emptying at regular intervals without the
necessity of discharging a large volume
of heating water. The sludge trap may be
combined with a fi lter, a fi lter with a sieve
alone is not suffi cient protection.
In the case of clogging of the boiler with dirt
from the heating system, these problems
or problems caused by other clogging are
not covered by the boiler’s warranty. The
fi lter and sludge trap must be checked
and cleaned regularly.
The requirements for utility water
properties are defi ned in STN 83 0616 (for
drinking water STN 75 7111). If the water
has a combined calcium and magnesium
concentration greater than 1.8 mmol/l, it is
useful to implement other “non-chemical”
measures against incrustation (e.g. use of
magnetic or electrostatic fi eld).
The tank must not be exposed to the
effects of:
- higher pressures than the maximum
operational pressure;
- direct effects of fi re or temperatures
higher than ordinary working and climatic
conditions
- impact, collision, force on the tank
vessel, shakes and vibrations (with the
exception of manifestations during actual
operation – i.e. circulation of heating
water and fi lling of utility water).
If the hot water issue points (cocks)
are located very far from the boiler, it
is possible to connect further piping,
creating a circuit with constantly fl owing
hot water between the boiler and cocks
(hot water circulation circuit). A hot water
outlet is used for the piping from the boiler
to the cocks, the return piping from the
cocks to the boiler is connected to the
“circulation” outlet. With the introduction of
hot water circulation there is no discharge
of cold water from the cock. The hot water
supply is increased by the volume of the
circulation piping – the length of heating
may be perceptibly increased by this or at
the same time also by ineffi cient insulation
of the piping of the circulation circuit.
The pump for hot water circulation is not
controlled from the boiler and must meet
the hygiene requirements.
If there are special requirements for
relocation of the boiler (e.g. prevention of
damage to covers, limited passage profi le
etc.) it is possible to partially disassemble
the boiler from the assembled state in
which it is delivered.
It is necessary to maintain a suffi cient
space around the boiler in order to
ensure that handling of the boiler and
its accompanying equipment during
installation and operation can be
performed safely.
