Humidification control (HumCtl11)

Overview

The application function "Humidification control 11" (HumCtl11) coordinates one or more humidification devices in the room segment to maintain room humidity at the required level.

Main features:

• Room relative humidity control
• Humidity monitoring alarm support
• Humidity setpoint configurable per room operating mode

Humidification – Issues of concern

Condensation from humidified air can manifest in unexpected places. Moisture migrates through the building and can find its way into external walls and between layers of construction materials. Condensation hidden inside walls can be a disaster.

Issues of concern include:

• Water spray where it is not needed (for example, water collection inside duct)
• Water spray when it is not needed (for example, seasonal high humidity)
• Ineffective high limit control, duct air
• Bends and changes in the duct; obstructions in the duct
• Ineffective temperature control (too cold air causes condensation)

CAUTION

Humidification Hazards

Humidification in building control introduces risk of material property damage and unsafe conditions. Personnel without the background or responsibility for these issues must adhere to the following:

1. DO NOT select room humidity setpoints.
2. DO NOT select which modes enable and disable humidification.
3. DO NOT pick the method for high limit control in the duct.
4. DO NOT choose not to apply high limit control – send RFI if it is not in the spec.
5. DO NOT alter dispersion tube Location or Pitch. If instructions are unclear contact the Humidifier Representative.
6. DO NOT jumper anything in the package unit without written authorization from Humidifier Representative.
7. DO NOT leave the Humidity system energized and untested.
8. DO NOT energize Humidifier before the device has been commissioned.
9. On all of these points, follow the spec. If the spec does not specify, then you must send an RFI.

Function

HumCtl11 receives humidity sensor readings from the segment(s) via chart input pin and compares this to the present humidity setpoint. The PID humidity controller calculates a demand output which is distributed to the room segment(s) by the group manager.

Operating mode effects
HumCtl11 enables/disables the humidification function and selects the humidity setpoint based on Room operating mode and Plant mode. See following table and also Configuration section.

Available signal

An "Available" signal (indicating whether or not humidifying equipment is available to be used) is collected from the room segments by the group manager. If no humidifying equipment is available, the PID is disabled to prevent integral accumulation.

Humidification request to segments
HumCtl11 communicates the humidification demand (PID output) and the enable/disable status of the humidification function to segment humidifiers via group data exchange. These two dynamic values (demand and enable/disable) are combined into one request signal as shown in the following table.

Feature configuration

Feature selections for "Room HVAC coordination" are accessed via the Application configuration task in the Configuration component.

Configuration

Objects

Parameters