T 2178 EN
Type 43-8 and Type 43-8 N Temperature Regulators with Hydraulic Controller
Series 43 Self-operated Temperature Regulators

Application
Temperature regulation of instantaneous water heaters in small district heating units (single- or two-family dwellings).
The valve closes when the temperature rises

The regulators are suitable for use with plate heat exchangers
for domestic hot water (DHW) heating, particularly in small
residential units. Fast-responding thermostats regulate the water temperature to the desired value without delay while thehydraulic control element closes the control valve immediately
after tapping has been completed. This prevents the heated
DHW from reheating. In addition, temperature peaks do notoccur any longer, preventing scaling (lime deposits) in theheat exchanger.

Regulator including
accessories and indicatedheat exchanger

Moreover, the regulator switches to a reduced idle temperature that prevents the heating water supply lines from coolingoff. This ensures that hot water is immediately available forthe next tapping.
The connections available as accessories enable operation
with or without circulation of the heated DHW.

Fig. 1: Type 43-8Temperature
Regulator with
Hydraulic Controller

Special features–

Low-maintenance proportional regulators requiring noauxiliary energy–

Control of small instantaneous water heaters–

Compact design–

Easy operation and installation–

Prevention of temperature peaks and reduction of loss
during idle operation (reduced idle temperature)–

Stable control at a tapped rate of 2 l/minute or higher–

Idle temperature regulation–

Fast-responding vapor pressure thermostats

Versions
The Type 43-8 and Type 43-8 N Regulators function the sameway, the only difference between them being that the technical features of the Type 43-8 N have been tailored to the requirements of local heat supply networks. Its overall height isapprox. 20 mm lower than that of the Type 43-8. As a result,
the regulators are not interchangeable.

The regulators consist of a control thermostat (vapor pressurethermostat), a hydraulic control unit and a valve.
Type 43-8 (43-8 N)
Type 2430 Vapor Pressure Thermostat · Set point range 45to 65 °C · In combination with Type 2432 Valve (2432 N) ·Red brass or hot-pressed brass body · DN 15 · PN 25(PN 16) · Suitable for liquids up to 130 °C (120 °C) · Max.
permissible differential pressure ∆p = 20 bar (4 bar) · KVS 2.5· Sensor made of CrNiMo steel · Observe mounting position.
Type 2438 Hydraulic Controller · Red brass body · Idle temperature approx. 8 K (optionally 15 K) below adjusted set
point · Required differential pressure at control element 0.4 to0.6 bar · PN 16SAMSON AKTIENGESELLSCHAFT · Weismüllerstraße 3 · 60314 Frankfurt am Main, Germany
Phone: +49 69 4009-0 · Fax: +49 69 4009-1507 · samson@samsongroup.com · www.samsongroup.com

Edition February 2022

Principle of operation (Fig. 2)
Fast-responding vapor pressure sensors are used to regulate
the temperature of instantaneous water heaters.
The temperature of the heated DHW creates a pressure in thesensor that corresponds to the actual pressure. This pressure istransferred through the capillary tube (8) to the operating element (13) and converted into a positioning force, which iscompared to the force of the set point spring (10). The force
ratio causes the plug in the valve (1) to move.
Depending on the travel, an annular gap forms between theseat (2) and the plug (3) that determines the flow rate of theheating 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 difference of ∆p = p1– p2
is created above the baffle plate (6). The resulting force
opposes the force of the compression spring (7) that acts inclosing direction and causes the valve (1) to open. Once hotwater tapping has been completed, the pressure balance isrestored. The force of the compression spring causes the valve
plug to move in the closing direction and the heat flow isinterrupted. At the same time, the temperature set point of thethermostat drops by approx. 8 K (optionally 15 K) to reachthe reduced idle temperature. As a result, reheating withtemperature peaks as well as cooling off of the supply lines isprevented. This ensures that hot water is immediately
available for the next tapping.

Type 2430 Control
Thermostat

Installation
To fully use the fast response behavior of the sensor (vaporpressure), the sensor must also be installed at the best possible
location. In instantaneous water heater, this location is directly
upstream of the outlet where the heated water flows out of theheat exchanger and upstream of the inlet where the hot waterflows into the heat exchanger.
–

9

Installation only without thermowell.

–Observe a distance of approx. 5 mm between the tipof the sensor and the rear of the housing.

–

Install the plate heat exchanger in such a way that theheating water flows vertically between the plates.

–

The heat exchanger connections for cold water and(district heating) water return pipe are located at thebottom; the connections for hot water and (districtheating) water flow pipe can be located at the top.

–1)

2

The ambient temperature at the set point adjuster mustnot be higher than 35 °C.

Other versions on request

8

Type 2438 HydraulicController

76

Cold waterp1
supplyp2

Cold water connection
to heat exchanger(turned into the planeof projection)

Type 2432
Valve
Heating water
return flow

5432
1

1
2
3
4
5
6
7

Valve body
Seat (exchangeable)
PlugPlug stem
Valve spring
Baffle plate
Compression spring

8 Capillary tube
9 Set point adjuster
10 Set point spring
11 Operating bellows
12 Pin of operating element
13 Operating element

Fig. 2: Functional diagram

Principle of operation · Vapor pressure thermostat
The temperature sensor is filled with a liquid which evaporates
depending on the temperature. As a result, a pressure in proportion to the temperature is created in the sensor. This pressureis transmitted to the operating bellows through the capillary
tube and converted into a positioning force. This force moves
the valve plug depending on the set point adjustment.
Plate heat exchanger

Install the temperature sensor such that the sensor
reaches horizontally into the hot water duct when theheat exchanger is mounted, observing a maximum
deviation of ±5° from the horizontal position. Thenotch at the end of the sensor must point upward (seeView A).

–13121110

Vapor pressure thermostat
Thermostat operating according to the vapor pressure principle. Due to the fast response time of approx. 3 s, these thermostats are particularly suitable for use in plate heat exchangers 1).

Temperature sensor
Vapor pressure thermostat

Hot water outlet

Amax. ±5°5 mmAdapter withtemperature
sensorFig. 3: Installing the sensor––View A
Temperature sensor, notch facing upward

The temperature regulator cannot be combined withsafety regulators (e.g. STM, STL).
For instantaneous water heating with a plate heat exchanger and Type 43-8, we recommend using the sensor Ø12x190 mm or Ø12x160 mm in the horizontal
mounting position.

T 2178 EN

Table 1: Technical data
Type 2432 Valve

Type 43-8

Type 43-8 N

Valve size

DN 15

KVS coefficient

2.5

Pressure rating

PN 25

PN 16

Max. perm. differential pressure Δp20 bar

6 bar

Max. permissible valve temperature

130 °C

120 °CType 2430 Control Thermostat
Set point range

45 to 65 °C

Capillary tube

2 m (5 m as special version)Max. perm. temperature at the sensor

30 K above the adjusted set point

Max. perm. temperature at the set point
adjuster

35 °C

Perm. pressure at sensor

PN 40

Type 2438 Hydraulic Controller
Required differential pressure (pressure loss)
across the control unit on the cold water side

0.4 bar with a tapping rate up to 10 l/minute
0.5 bar with a tapping rate up to 20 l/minutePressure rating

PN 16

Idle temperature

Approx. 8 K (optional 15 K) below the adjusted set point

Min. temperature difference between flow
temperature and temperature set point

10 K

Max. flow rate

20 l/minute

Table 2: Materials · Material numbers according to DIN EN
Body
Valve seat
Valve plug

CC499K (red brass, Rg 5)

CW602N (hot-pressed brass)

Stainless steel 1.4305

CW602N

1.4104 and brass, resistant to dezincification, with EPDM soft seal

Valve spring and spring in Type 2438

Stainless steel 1.4310

Baffle plate
Temperature
sensorPOMCapillary tube

CopperSensor

CrNiMo steel

Set point adjuster

PETP, glass fiber reinforced

Domestic hot water heated in an instantaneous heating
system with Type 43-8
1Application range

4

The quality of the domestic water to be controlled determines
the field of application of the regulator. The water quality mustmeet the requirements listed below.
Table 3: Domestic water quality

2

DHW
pH

Min. 7/max. 10

Chloride concentration

Max. 150 mg/l

HCO –3SO 24>1.5

Carbonate hardness

Min. 5° dH (German hardness)

Total hardness

Max. 12° dH

T 2178 EN31 District heating supply
District heating return
2flow

3 DHW
4 Domestic hot water

Fig. 4: Domestic hot water heated in an instantaneous heatingsystem

3

Accessories
Accessories

Cold water supply · Corrugated pipe (4) with/without
circulation pipe connection (2) for connection to heatexchanger (G ¾ or G 1)
Including flat gasket

Connecting dimensions for heat exchanger

Distance a in mm
Connection (4) · Corrugated pipe

Heating watersupplyHot water

1

5 mm

Heating water return pipe · Double nut (5) made of brass(G ¾ or G 1) for connection to heat exchanger · Welding end(3) with connection nut
Including flat gasket
Heat exchanger connection
Double nut (5)To hot water tappingpointConnections
G ¾ or G 1
Cold waterconnection
2G¾G1

340 to 45

48 to 52
69 to 734H≥260mm(240mm)1)

Connecting piece (1) to hot water tapping point (G ¾ or G 1)
with/without sensor pocket (G ¾ or G 1) · Including flat gasket· For temperature sensor Ø12, Rg 5

a5

Heating water
returnCold water

With/without circulation pipe1)

Fig. 5: Regulator with accessories

For Type 43-8 N

Dimensions in mm
Ordering text

Ø 12Type 43-8/Type 43-8 N
Temperature Regulator withHydraulic Controller

65

G¾160/190

G¾/G1Ø 76

DN 15 valve, KVS 2.5
Type ... heat exchanger
G ¾/G 1 heat exchanger connection
With or without circulation pipe
connection

2411)

Sensor (160 or 190 mm length)1535

With/without screw gland
Optionally, accessories ...
Optionally, special version ...

G¾30

G¾43651)

Dimensions

Specifications subject to change without notice

T 2178 EN

2022-02-14 · English

Fig. 6:

With Type 43-8 N: 221 mm