Strebel S-CB Px 120, Installation Operating & Maintenance Manual

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S-CB Px 120 Manual 75
11.3. Indirect hot water / calorifier
The following chapters describe the different functions of the boiler and their related “controlling behaviour set-
tings” as a central heating boiler with an indirect hot water function.
11.3.1. P
UMP AND
3-
WAY VALVE CONTROL
See chapter 19 for several installation examples of the boiler and the preferred functions. When the boiler is used
as an indirect boiler for both central heating and hot water function, this hot water function can be activated by
using a DHW pump or a 3-way valve.
P4 AB DHW Pump Config 0=Pump 1=TWV (display B1)
Use this parameter to program whether the flow to the indirect water tank (calorifier) is controlled by a pump (0 =
Pump) or a 3-way valve (1 = TWV).
11.3.2. T
ANK THERMOSTAT
An external thermostat can be connected to the boiler (connections 5-6). When there is a hot water demand and
the tank thermostat closes, the boiler will start for the hot water demand. The calorifier/tank pump will be activated
or in case of a 3-way valve, this valve will turn to the position to supply heat to the tank coil(s). In case of a heat
demand and hot water demand, the CH pump will switch off until the hot water demand ends.
P4 AB DHW Pump Config 0=Pump 1=TWV (display B1)
Use this parameter to program whether the flow to the indirect water tank (calorifier) is controlled by a pump (0 =
Pump) or a 3-way valve (1 = TWV).
11.3.3. T
ANK SENSOR
A tank sensor can be connected to the boiler. The tank (hot water) set point and related controlling parameters
are set in the boiler controller. A hot water demand is detected by the boiler, when the sensor (water) temperature
drops below the set point. The calorifier/tank pump will be activated or in case of a 3-way valve, this valve will turn
to the position to supply heat to the tank coil(s). In case of a heat and hot water demand at the same time, the
heating pump will switch off until the hot water demand is stopped (water temperature is reached).
P5 CA Hysteresis DHW tank temperature (display BF)
The amount of degrees that the hot water temperature in the indirect water tank/calorifier needs to drop relative to
the hot water set point, before the heat demand is transported to the boiler.