10
EB 2178 EN
Design and principle of operation
2.1
Material identification
number
Specifying the configuration ID, you can con
-
tact us to find out which material is used. The
configuration ID (2) is specified on the name
-
plate.
For more details on the nameplate, see
3 Design and principle of
operation
The Type 43-8 Regulator is used to control
the temperature of instantaneous water heat-
ers in small district heating units.
The devices consist of the Type 2430 Control
Thermostat (30) operating according to the
vapor pressure principle, the Type 2438
Hydraulic Controller (20) the Type 2432
Valve (1).
The temperature sensor is filled with a liquid
which evaporates depending on the tem-
perature. As a result, a pressure in propor-
tion to the temperature is created in the sen-
sor. This pressure is transferred through the
capillary tube (8) to the operating element
(13) and converted into a positioning force,
which is compared to the force of the set
point spring (10).
The force ratio causes the plug in the valve
(1) to move. Depending on the valve travel,
an annular gap forms between the seat (2)
and the plug (3) that determines the flow
rate of the heating water.
A temperature increase at the sensor causes
the valve plug to close, thus reducing the
flow rate of the heating water.
Upon tapping hot water, a pressure differ-
ence of ∆p = p
1
– p
2
is created above the
baffle plate (6). The resulting force opposes
the force of the compression spring (7) that
acts in closing direction and causes the valve
to open. Once hot water tapping has been
completed, the pressure balance is restored.
The force of the compression spring causes
the valve plug to move in the closing direc-
tion and the heat flow is interrupted. At the
same time, the temperature set point of the
thermostat drops by approx. 8 K (optionally
15 K) to reach the reduced idle temperature.
This prevents reheating with temperature
peaks as well as the supply lines from cool-
ing down.
This ensures that hot water is immediately
available for the next tapping.
Table 1:
Domestic water quality
DHW
pH
Min. 7/max. 10
Chloride concentration Max. 150 mg/l
HCO
–
3
SO
2-
4
>1.5
Carbonate hardness
Min. 5° dH (German
hardness)
Total hardness
Max. 12° dH
Summary of Contents for 43-8
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