Primary States (Heat Recovery Wheel with Bypass Dampers) - Johnson Controls - Metasys - LIT-12011147 - Software Application - Controller Configuration Tool - 15.0

Controller Tool Help

Brand
Johnson Controls
Metasys
Product name
Controller Configuration Tool
Document type
User Guide
Document number
LIT-12011147
Version
15.0
Revision date
2022-11-18
Language
English

Cooling Mode

  • Off: Turn everything off. The face and bypass damper outputs are set to 0%.

  • Max: Operate the energy recovery wheel with the face and bypass dampers positioned for full flow through the wheel. The wheel operates at maximum capacity during cooling, since the heat recovery device cannot produce enough cold air to condition the space.

  • Hold: Hold the outputs at their current position.

Heating Mode

  • Off: Turn everything off. The face and bypass damper outputs are set to 0%.

  • Max: Operate the energy recovery wheel with the face and bypass dampers positioned for full flow through the wheel.

  • Hold: Hold the outputs at their current position.

  • T Control: Modulate the bypass damper position to control the Process Variable at the Setpoint. This mode is used for heating only, since the heat recovery device can provide more heat than what is required to condition the space.

  • LL-T Control: Modulate the bypass damper position to control the Low Limit Variable. The low limit variable is the air temperature leaving the energy wheel, and this mode is used to prevent the leaving temperature from dropping below freezing. If the Limit Variable is reliable, the module controls the output in order to maintain the Limit Variable at the Limit Setpoint.

State

  • Off: Turn everything off. The face and bypass damper outputs are set to 0%.

  • Max: Operate the energy recovery wheel with the face and bypass dampers positioned for full flow through the coil.

  • Hold: Hold the outputs at their current position.

  • T Control: Modulate the bypass damper position to control the Process Variable at the Setpoint. This mode is used for heating only since the heat recovery device can provide more heat than what is required to condition the space. On the other hand, during cooling, the heat recovery device cannot produce enough cold air to condition the space

  • LL-T Control: Modulate the bypass damper position to control the Low Limit Variable. The low limit variable is the air temperature leaving the energy wheel, and this mode is used to prevent the leaving temperature from dropping below freezing. If the Limit Variable is reliable, the module controls the output in order to maintain the Limit Variable at the Limit Setpoint.

Table 1. Heat Recovery Wheel with Bypass Dampers Command Hierarchy

Heat Recovery Suitability

Cooling Mode

Heating Mode

PID Tuning Reset

State

*

Hold

*

Reset 1st PID

T Control

Hold

Reset 2nd PID

LL-T Control

*

Hold

Reset 1st PID

T Control

Hold

Reset 2nd PID

LL-T Control

None

 

*

*

Off

Cool

Off

*

Off

Max

*

Max

Hold

*

Hold

Heat

*

Off

Off

Max

Max

Hold

Hold

T Control

T Control

LL-T Control

LL-T Control