
10 EB 2178 EN
Design and principle of operation
2.1 Material identication
number
SpecifyingthecongurationID,youcancon-
tactustondoutwhichmaterialisused.The
congurationID(2)isspeciedonthename-
plate.
For more details on the nameplate, see
Fig.1.
3 Design and principle of
operation
TheType43-8Regulatorisusedtocontrol
the temperature of instantaneous water heat-
ers in small district heating units.
ThedevicesconsistoftheType2430Control
Thermostat (30) operating according to the
vaporpressureprinciple,theType2438
HydraulicController(20)theType2432
Valve(1).
Thetemperaturesensorislledwithaliquid
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)
andtheplug(3)thatdeterminestheow
rate of the heating water.
A temperature increase at the sensor causes
the valve plug to close, thus reducing the
owrateoftheheatingwater.
Upon tapping hot water, a pressure differ-
enceof∆p=p1– p2is created above the
bafeplate(6).Theresultingforceopposes
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-
tionandtheheatowisinterrupted.Atthe
same time, the temperature set point of the
thermostatdropsbyapprox.8K(optionally
15K)toreachthereducedidletemperature.
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.
Table1: Domestic water quality
DHW
pH Min. 7/max. 10
Chlorideconcentration Max.150mg/l
HCO –
3
SO 2-
4
>1.5
Carbonatehardness Min.5°dH(German
hardness)
Total hardness Max.12°dH