Primary States (Heat Recovery Enthalpy Suitability Determination) - 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

The Heat Recovery Suitability output is set to Cool if heat recovery is allowed, the temperature inputs are reliable, and Clg HR is True. The Clg HR tells the command hierarchy whether the exhaust air is cold enough with respect to the outside air temperature to make cooling energy recovery suitable. The exhaust air temperature must be below the outdoor air temperature by the Deadband/2 before the CLG HR is set to True.

The Heat Recovery Suitability output is set to Heat if heat recovery is allowed, the temperature inputs are reliable, and Htg HR is True. The Htg HR tells the command hierarchy whether the exhaust air is warm enough with respect to the outside air temperature to make heating energy recovery suitable. The exhaust air temperature must be above the outdoor air temperature by the Deadband/2 before the Htg HR is set to True.

The Heat Recovery Suitability output is set to None if Heat Recovery isAllowed is False, any temperature input is not reliable, or both Clg HR and Htg HR are False.

Table 1. Heat Recovery Enthalpy Suitability Determination Command Hierarchy

Heat Recovery IsAllowed

Clg HR

Htg HR

Heat Recovery Suitability

False

*

*

None

True

False

False

None

True

True

None

True

False

Cool

False

True

Heat