13
!
Please note
Shutting down from full load can result in high
material stress and material damage.
If a system with a higher ranking building man-
agement system takes over the temperature
control of the boiler, adjust the settings at the
temperature controller TR. Set the electronic
temperature controller to at least 10 K below the
mechanical temperature controller.
Expansion vessel and system pressure
Note
Observe the information provided by the manufacturer
of the expansion vessel (DEV).
Check when system is cold.
1.
Drain the system or close the cap valve on the
expansion vessel and reduce the pressure until the
pressure gauge indicates "0".
Note
The pre-charge pressure of the expansion vessel
(p
0
) is made up of the static system pressure (p
St
)
(= static head) and a supplement (p
0
= p
St
+ sup-
plement).
The supplement depends on the high limit safety
cut-out setting.
Supplement
100 °C:
0.2 bar (20 kPa)
110 °C:
0.7 bar (70 kPa)
2.
If the pre-charge pressure of the expansion vessel
is lower than the value calculated using the for-
mula, top up with sufficient nitrogen to achieve this
value.
3.
Refill with water until the charge pressure is 0.2
(20 kPa) higher than the pre-charge pressure of
the expansion vessel when the system is cold.
4.
Mark this value on the pressure gauge as the mini-
mum charge pressure.
Pump controlled pressure maintaining systems
Note
In heating systems with automatic pressure maintain-
ing equipment or deaeration systems (operating
according to the pressure reduction method for deaer-
ation), we recommend installing an expansion vessel
(DEV) for individual boiler protection.
The expansion vessel must be able to absorb the
expansion volume of the heating water in the boiler.
Minimum size 35 l
This expansion vessel reduces the frequency and
severity of pressure fluctuations; the runtime of the
pressure maintaining pump is improved and therefore
the operational reliability and service life of system
components is increased.
Failure to observe these
recommendations may result in damage to the
boiler or to other system components.
Check the pressure maintaining system in line with the
manufacturer's instructions. Limit pressure fluctuations
to the lowest possible differential. Cyclical pressure
fluctuations and more significant pressure differentials
point towards a system fault. Remedy such faults
immediately to prevent damage to other components
in the heating system.
Commissioning, inspection, maintenance
Checking the temperature controller setting if a building management system
is used (DCC system)
5692910
