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

 

 

 

Sequences

 

Y

Output signal

 

TR

Room temperature

YH1

First stage

 

SpH

Effective heating setpoint

YH

Electric heating coil

 

 

 

Figure: 1-stage electric heating coils

 

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

 

Y

Output signal

 

TR

Room temperature

YH1

First stage

 

SpH

Effective heating setpoint

YH2

Second stage

 

YH

Electric heating coil

YH3

Third stage

 

 

 

Figure: 3-stage electric heating coils

 

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

Enable overtemperature detector input

0:No
1:Yes

EnOvrTDetIn

0:No

WARNING
Electric heat coils require safety limit thermostat

Improper installation of electric heating coils can result in fire and cause destruction of life and property.

  1. Install a high temperature cut-out switch on all electric heating elements.
  1. Ensure that all wiring and installation conform to applicable safety codes and regulations.