1. Module 5: Wiring and Controls
TrueSTEAM™ Humidification Systems
Module 5: Wiring and Controls
Welcome to the fifth module of the TrueSTEAM training series – Wiring and Controls. Let’s get started.

2. Module 5: Wiring and Controlling TrueSTEAM
What dips to set for different controls
How to wire different controls
When to choose one control over another
Module five will specifically focus on wiring and configuring different control options for TrueSTEAM Humidification Systems. You'll get an understanding of available TrueSTEAM controls and how to properly wire and configure TrueSTEAM to work with these different controls. Proper control setup ensures that TrueSTEAM will operate to maximize homeowner comfort.
Key Learning
Which humidity controls to use and how to configure them

3. Getting Started Unplug TrueSTEAM and remove cover Locate DIP Switches
DIP 1-2 = Flush timings
DIP 3 = RedLINK
DIP 4 = Power monitoring
DIP 5 = Air proving
DIP 6 = not used
Before starting any wiring or configuration of TrueSTEAM, make sure TrueSTEAM is unplugged.
Once the cover is removed, you will see a series of six DIP switches to the left of the L. E. D. lights. These switches configure the TrueSTEAM operation based on the control you choose and the water quality of the home that TrueSTEAM will be installed in.
DIP switches one and two are for configuring the water quality flush cycles. Since these are related to operation and maintenance, we will discuss these in greater detail in module six.
For this module regarding the wiring of TrueSTEAM, we will focus on primarily on DIP switches three through five. 1 2 3 4 5 6

4. DIP 3 – RedLINK™ Wireless Technology
DOWN: RedLINK disabled, use conventional terminals
UP: RedLINK enabled, use ABCD terminal
Prestige HD Thermostat
Wireless Adapter
The third DIP switch from the left enables or disables the use of a RedLINK wireless humidity control. When in the down position, the RedLINK terminals are disabled, which is the factory default setting. In this position, you will wire to the conventional terminals on TrueSTEAM, which we’ll discuss later in this module.
When DIP three is in the up position, the RedLINK terminal is enabled. By connecting a wireless adaptor to the A, B, C and D terminals, TrueSTEAM will be able to communicate with RedLINK humidity controls, such as Prestige.
Conventional Terminals

5. DIP 4 – Power Monitoring
Down: TrueSTEAM looks for R and C input before allowing humidity
Use when humidity control is separate from system control
UP: TrueSTEAM R and C input disabled
Use when humidity control is integrated with system control
The fourth DIP from the left is for monitoring the HVAC system transformer to ensure there is power before allowing humidity. There are two ways this can be done based on the humidity control you select.
First, if you are using a humidity control that is separate from the furnace and air conditioner control, such as a manual humidistat, you would set DIP four in the down position. Next, you will wire the system transformer R and C to the TrueSTEAM terminals R and C. When humidity is needed, TrueSTEAM will first verify the system has power before allowing humidity to be produced, based on the assumption that if the system transformer has power, so does the system fan. In this application, DIP four provides a safeguard against humidifying without the system having power.
If you are using a humidity control that is integrated with the system control, such as a VisionPRO IAQ, then set DIP four in the up position. Because a system control gets its power from the system transformer and controls both the system fan and humidifier, it is not necessary for TrueSTEAM to monitor the R and C input. Keep in mind that the images shown here and in the following three slides are not complete diagrams and are only meant to depict the application. Complete diagrams for each available Honeywell control will be explained later in this module.

6. System Fan Regulation
Breaking G: Use when humidity control is separate from system fan control.
Fan delay advantage
Not breaking G: Use when humidity control is integrated with system fan control.
Simple wiring advantage
Airflow is needed to dispense humidity into the living space and prevent condensation from forming in the duct, so before discussing DIP switch number five, we will discuss a configuration that allows TrueSTEAM to control the system fan when humidity is needed.
If the humidity control you use does not monitor or control the system fan, it is critical that TrueSTEAM does so when humidity is needed. This can be done by breaking the G connection between the thermostat and HVAC system - passing it through TrueSTEAM as shown in the left hand picture.
In this wiring set-up, a call for humidity will come from the humidity control, and just before steam production begins, TrueSTEAM will automatically energize the system fan. An advantage of this set-up is that TrueSTEAM utilizes a thermistor inside the tank to delay the fan activation until just before humidity is created, which can minimize fan drafts into the living space.
The second choice for fan regulation is with a control that integrates the system fan control and humidifier control, such as VisionPRO IAQ. With this type of control, you can configure the software settings to activate humidification and the fan as desired. The advantage of this configuration is that wiring is greatly simplified, however, because the thermistor inside TrueSTEAM’s tank isn’t being used, the fan will automatically come on based on the control’s software set up, which is defaulted to turning the fan on immediately when there is a call for humidity.

7. DIP 5 – Air Proving DOWN: Air proving disabled.
UP: Air proving enabled.
Added safeguard for air movement
With this basic understanding of system fan regulation, there is a fifth and final DIP switch configuration to consider for your application. DIP five allows for the installation of a separate accessory air proving device, such as a sail switch or differential pressure switch as shown here.
We have covered how power monitoring and system fan regulation can be achieved through different wiring and configuration. These features will ensure the system has power, and will confirm that G is energized to move air. Tying in an air proving device will confirm that air movement is physically present immediately after the G call is sent.
To wire this type of configuration, first set DIP four down, and DIP five up. This will make TrueSTEAM look for the R and C input, and will check for air movement after the G call is sent. TrueSTEAM will then check that the C connection is made. If an air proving device with a normally open default is wired between TrueSTEAM C and system C, it will make contact when air movement is present and allow humidity into the duct.

8. Complete Diagrams For Provided Humidity Controls
Now that we’ve covered the different DIP switch settings, we will illustrate complete diagrams for each of the controls that are available with TrueSTEAM, starting with a manual humidistat.

9. Wiring a Manual Humidistat with Dry Contacts
Wiring a mechanical humidistat such as H8908 (eighty nine O eight) requires that the power monitoring and system fan regulation be configured through TrueSTEAM.
To do this, break the G connection between the thermostat and HVAC system, and pass it through TrueSTEAM as shown. Next, wire the R and C terminals on TrueSTEAM to R and C terminals on the HVAC system. Ensure that DIP four is in the ‘down’ position. Last, wire the contacts of the H8908 control to TrueSTEAM’s “H.U.M” terminal.

10. Wiring TrueIAQ®
Wiring TrueIAQ to control TrueSTEAM is similar to the H8908 wiring discussed earlier in the module, except that TrueIAQ will require 24 Volt power and software configuration.
To do this, complete the steps as outlined on the H8908 configuration. You will then wire TrueSTEAM’s 24 volt terminals to R and C on TrueIAQ. Last, in the TrueIAQ installer set-up, set code number twenty-five to three.

11. Wiring VisionPRO® IAQ DIP 4
The VisionPRO IAQ is a control that integrates HVAC system control with humidification control. Because VisionPRO IAQ is powered by the system transformer and regulates the fan, the wiring for VisionPRO IAQ is much simpler.
Simply set DIP four to the up position, and wire the “H.U.M.” terminals on TrueSTEAM to the H. U. M. terminals on the equipment interface module of VisionPRO IAQ. Last, in the VisionPRO installer set-up, set code number zero three seven four to one.

12. Wiring VisionPRO® IAQ With Fan Delay
DIP 4
If you wish to have the VisionPRO IAQ utilize the TrueSTEAM thermistor for fan delay, set DIP four to the down position. Next, break the G connection between the equipment interface module and the HVAC system and pass it through TrueSTEAM as shown here. Then, wire the R terminal of TrueSTEAM to the R terminal of the equipment interface module. Last, in the VisionPRO installer set-up, set code number zero three seven four to three.

13. Prestige™ RedLINK Connection
DIP 3
DIP 4
The simplest method for wiring a TrueSTEAM control is through Honeywell’s RedLINK technology. Start by setting DIP three and four to the up position, then connect the wireless adapter to the A, B, C and D terminals on TrueSTEAM. Last, connect Prestige wirelessly to TrueSTEAM in the software set up.
The greatest benefit of using this type of humidification control is that regardless of the equipment type, brand or model, wiring is universal. The installer does not need to go through extra steps of wiring TrueSTEAM to the system, it’s all done through the control.

14. Wiring to TrueIAQ™ in a Zoned Application
You may come across an application where zoning is present. This diagram shows how to connect TrueSTEAM to a wired humidistat – such as TrueIAQ in a zoned application. In this application if an air proving switch is used, set the TrueSTEAM DIP four to the down position and DIP five to the up position. Then, connect the thermostats, dampers, transformers and sensor wires according to the TrueZONE HZ432 (four three two) panel instructions. Last, in the TrueIAQ installer set-up, set code number twenty-five to three.

15. Wiring to a VisionPRO® IAQ in a Zoned Application
If you are using a thermostat to control TrueSTEAM in a zoned application, follow this diagram. If an air proving switch is used, set the TrueSTEAM DIP four to the down position and DIP five to the up position. Then, connect the thermostats, dampers, transformers and sensor wires according to the TrueZONE HZ432 panel instructions. Last, in the VisionPRO installer set-up, set code number zero three seven four to three.

16. RedLINK Connection in a Zoned Application
If you are using RedLINK technology in a zoned application with TrueSTEAM, follow this diagram.
If an air proving switch is used, set the TrueSTEAM DIP four to the down position and DIP five to the up position. Then, connect the thermostats, dampers, transformers and sensor wires according to the TrueZONE HZ432 panel instructions. In the Prestige Installer setup, program humidity calls to ‘Humidify Independent of Fan”. Remember, that one TrueZONE HZ432 panel with a RedLINK adapter will wirelessly communicate with up to three additional zones that have RedLINK thermostats.

17. Wiring to a Dedicated Fan
If you are installing TrueSTEAM in a home without ducting, you can wire in a remote fan to distribute humidity into the living space as shown. Refer to the installation manual for further specific installation requirements.

18. Wet Switch Wiring in a Finished Space
Finally, if TrueSTEAM is being installed in or above a finished space, it is recommended to install a drip pan with a water shut-off sensor underneath the water connections to TrueSTEAM. Honeywell recommends using the Diversitech WS1 wet switch. Set DIP four and five to the down position and wire the wet switch into TrueSTEAM using the 24 volt and C terminals.

19. Support Materials
Detailed Training Materials on Installation Available! Visit Enter literature form: # : TrueSTEAM Installation Manual
Be sure to visit to view and download additional TrueSTEAM support materials such as TrueSTEAM installation manuals and other supplemental white papers.

20. Module 5: Wiring and Controlling TrueSTEAM
What dips to set for different controls
How to wire different controls
When to choose one control over another
In this module, you learned how to wire and configure different control options for TrueSTEAM Humidification Systems. Additionally, you learned about the different TrueSTEAM controls and how to properly wire and configure TrueSTEAM to work with the different controls.
This concludes Module five.
Key Learning
Which humidity controls to use and how to configure them