All DXR2 application types include a hot water radiator application. Each DXR2 can control two hot water radiators via triac or analog outputs. For hot water radiators, the controller operating modes modulating or 2-point can be configured.
Plant diagram
Figure: Example of radiator application
Key:
DXR2… | Automation station |
| R1 | Room operator unit |
Rad | Radiator-type heaters |
| D1 | Presence |
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| D2 | Window contact |
Sequences
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Y | Output signal |
| TR | Room temperature |
SpH | Effective heating setpoint |
| SpC | Effective cooling setpoint |
YH | Heating valve |
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Figure: Modulating heating sequence
Actuators
The DRX2 automation station controls radiator valves via triac or analog outputs, regardless of available I/Os. 3-position actuators, thermal pulse width modulation (PWM) actuators, PWM actuators with return spring can be connected to the triac outputs.
A maximum of 1 thermal valve can be connected to each triac on the DXR2 with AC 230 V power. PWM actuators with spring return are not supported.
Valve protection
Valve actuators are operated from time to time to prevent them from seizing after long periods of inactivity (e.g. heating valve during the summer). The valve actuator is controlled to lose as little heating energy as possible.
The central function for the hot water supply chain performs the valve protection function and can be changed in the parameters as needed.
Description | Name | Default value |
|---|---|---|
Kick value | KickVal | 50% |
Kick time | TiKick | 2 min |
Kick cycle | KickCyc | 500 h |
Downdraft compensation
The downdraft compensation function slows down sinking cold air current at large window surfaces and prevents in this manner a cold wall effect on large, cold surfaces. The function activates the radiator if the outside temperature drops below a configured value by increasing the minimum radiator control to a higher value. A linear reset function implements the downdraft compensation. The control sequence is only active in the Comfort room operating mode. The following graphic provides the factory settings for the downdraft compensation parameters.
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Y | Output signal |
| TOa | Outside air temperature |
Y1 | 100 % |
| X1 | -5 °C |
Y2 | 0 % |
| X2 | 10 °C |
Figure: Downdraft compensation characteristic curve