One electric heating coil can be configured for VAV applications. The DRX2 room automation station controls electric heating coils via triac or analog outputs, regardless of available I/Os. Single-stage, 2-stage, 3-stage, and modulating electric heating coils are supported.
Plant diagram
Figure: Example of a VAV application with electric heating coils
Key:
DXR2… | Automation station |
| R1 | Room operator unit |
YS | Supply air VAV |
| D1 | Presence |
YR | Electric heating coil |
| D2 | Window contact |
T | Over temperature contact |
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Sequences
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Y | Output signal |
| TR | Room temperature |
YH1 | First stage |
| SpH | Effective heating setpoint |
YH | Electric heating coil |
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Figure: 1-stage electric heating coils
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Y | Output signal |
| TR | Room temperature |
YH1 | First stage |
| SpH | Effective heating setpoint |
YH2 | Second stage |
| YH | Electric heating coil |
Figure: 2-stage electric heating coils
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Y | Output signal |
| TR | Room temperature |
YH1 | First stage |
| SpH | Effective heating setpoint |
YH2 | Second stage |
| YH | Electric heating coil |
YH3 | Third stage |
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Figure: 3-stage electric heating coils
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Y | Output signal |
| TR | Room temperature |
YH | Electric heating coil |
| SpH | Effective heating setpoint |
Figure: Modulating electric heating coils
Actuators
Electric heating coils, controlled via an analog output on the DXR2, can receive an enable via a relay or triac on the DXR2.
Safety thermostat
A binary overtemperature (open contact) protection can be connected on the DXR2 for all versions of the electric heating coil application. The application switches off the electric heating coils at device protection priority if overtemperature protection is enabled.
Description | Name | Default value |
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Enable overtemperature detector input 0:No | EnOvrTDetIn | 0:No |
WARNING
Improper installation of electric heating coils can result in fire and cause destruction of life and property.
- Install a high temperature cut-out switch on all electric heating elements.
- Ensure that all wiring and installation conform to applicable safety codes and regulations.