General Information
6
Diagram no. 1 A diagram of the boiler heating circuit hydraulic loss
If the central heating system is fitted by thermostatic valves, it is necessary in order that their correct function
was ensured and noisiness was restrained. For usual installations when the C.H. system is connected on the
boiler, it is necessary to keep the dynamic overpressure in the system at the value of
8 - 15 kPa (0.8 - 1.5 m column of H
2
O). For this purpose a pressure relief valve must be fitted (e.g. Heimeier
HYDROLUX DN 20) in the system. It will be set on the required value of the pressure. The pressure relief
valve is usually fitted next to the boiler.
If the heating system is in a large distance from the boiler, the pressure relief valve may be placed at the
place of the system branching with advantage. The pressure relief valve ensures also the required minimal
flow through in the boiler in a case of radiator valves closing.
Values of the maximal overpressure have been also stated in the graph. They are intended for the individual
adjustments of power output grades of the circulating pump that is available in the heating system. Minimal
flow through the boiler drum is 500 l / hour. From the graph, it follows that the required flow through won't be
reached by exceeding of the maximal dynamic overpressure.
Fig. no. 1
The main boiler dimensions
Volume Flow through of Heat Transfer Media, Water [litters per an hour]
U
ti
lis
a
b
le
O
v
e
rp
re
s
s
u
re
f
o
r
H
e
a
ti
n
g
S
y
s
te
m
[
k
P
a
]
