Primary States (Heat Recovery Wheel with 2 Pos Bypass Dampers) - Johnson Controls - Metasys - LIT-12011147 - Software Application - Controller Configuration Tool - 13.1

Controller Tool Help

Brand
Johnson Controls
Metasys
Product name
Controller Configuration Tool
Document type
User Guide
Document number
LIT-12011147
Version
13.1
Revision date
2019-12-04
Language
English
  • Off: Set the output to the heat recovery wheel to off.

  • Max: Operate the energy recovery wheel at the maximum wheel speed. Turn off the Heat Recovery CloseOpen.

  • Hold: Hold the outputs at their current position.

  • Limited Max: Operate the energy recovery wheel at the Limited Max Speed. Turn off the Heat Recovery CloseOpen.

  • T Control: Modulate the energy wheel speed to control the Process Variable at the Setpoint. This mode is used for heating only because the heat recovery device can provide more heat than what is required to condition the space. During cooling, the heat recovery device cannot produce enough cold air to condition the space. When Heat Recovery Percent Cmd is 0%, the Heat Recovery OpenClose is set to Open. When Heat Recovery Percent Cmd is any other value, the Heat Recovery OpenClose is set to Close.

  • LL-T Control: Modulate the energy wheel speed 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 to maintain the Limit Variable at the Limit Setpoint. When Heat Recovery Percent Cmd is 0%, the Heat Recovery OpenClose is set to Open. When Heat Recovery Percent Cmd is any other value, the Heat Recovery OpenClose is set to Close.

Table 1. Heat Recovery Wheel with 2 Pos 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

Limited Max

Limited Max

Hold

Hold

T Control

T Control

LL-T Control

LL-T Control