22
Higher pressure systems (e.g. in high buildings)
If pressures higher than 4,0 bar occur in the heating system, the best solution is to separate the system from the
boiler by means of a plate heat exchanger. Now the boiler pressure can still be under 4,0 bar and the boiler control
remains as described above.
Without plate heat exchanger, above 4,0 bar, a water pressure switch has to be built into the boiler instead of the
water pressure sensor - the maximum allowed value in the boiler now is 6,0 bar and the boiler control needs to be
adjusted.
6.15
Chemical water treatment
The chemical compatibility of several products for treatment of the central heating equipment has been tested on the
heat exchangers and the boilers. A list with the corrosion inhibitors in preventative and curative treatment for gas
fired central heating boilers can be supplied.
6.16
Under floor heating
When using an under-floor heating system of non-diffusion proof PVC pipes, the boiler circuit must be separated
from the heating circuit by means of a plate heat exchanger.
6.17
Flush the system with fresh water
The water of the boiler and heating circuit should be free of any particles, debris and pollution. Therefore, the com-
plete installation must always be thoroughly flushed with clean water before installing and using the boiler(s).
6.18
Installation examples
6.18.1 I
NSTALLATION CONTAINING ONE
S-
CB
+
400
/
550
CH
BOILER
valve
air separator
dirt separator
strainer (water
filter)
pressure relief
valve
siphon
pump
automatic air
vent
expansion ves-
sel
low loss header
S-CB
+
400/550
TOP VIEW
With the low loss header the boiler flow is not influ-
enced by system behaviour.
We advise to use a low loss header.
EXTERNAL SYSTEM PUMP can be controlled
by the boiler.
Often the system pump is externally controlled
and always running. System pump needs to run
when boiler is firing.
EXTERNAL
SYSTEM
PUMP (P3)
HEATING ZONE
