AC Settings

In addition to the configurable AC unit settings, a range of options is available for technicians to customize each air conditioning system.

These options can be accessed via iZone AC unit configuration settins and are detailed below.

Unit Auto Off

The Unit Auto Off feature can be enabled or disabled via the iZone AC unit configuration settings.

Functionality:

• When enabled, the AC unit will automatically turn off after a short delay if all zones are set to Closed.
• If the AC unit is manually turned On while all zones remain Closed, a message will appear on the screen informing the user that all zones are closed and the unit will shut down shortly.
• If a zone is immediately opened or switched to Climate mode, the AC unit will continue to operate normally.
• If no zones are opened or set to Climate within the delay period, the system will proceed to automatically power off the AC unit.

note

When Unit Auto Off is enabled, the AC unit will not turn off if zones are in Climate mode, even if all zones are satisfied and have temporarily closed. This ensures continued monitoring and readiness to respond to temperature changes.

Use In-Duct Energy

This is a unique feature of the iZone system and must be enabled in the AC Unit Configuration to operate. To take full advantage of this feature, the system must include:

• A supply air sensor (CDTS)
• Zones configured for temperature control (Climate mode)

How It Works:
When enabled, the iZone system monitors the temperature of the air in the ductwork and uses it to help bring zones closer to their set points-regardless of the AC unit’s current mode.

Example – Summer (Cooling Mode):

• The system is running in Cool mode.
• All zones reach their set points and the compressor cycles off.
• Over time, the air in the ducts warms up due to the heat in the roof space.
• If any Climate zone is below its set point, the iZone will open that zone and use the warmer duct air to gently raise the room temperature, reducing the need to restart the compressor.

Example – Winter (Heating Mode):

• In Heat mode, once all zones are satisfied, the system cycles off.
• The duct air begins to cool, especially if located in a cold roof space.
• If a Climate zone is above its set point, the iZone may open that zone to allow the cooler air to bring the temperature down.

This strategy helps maintain comfort while reducing compressor run time, improving energy efficiency and system performance.

Fault History

The fault history is recorded whenever the AC unit sends a fault message to the iZone system.

Please note, these faults are related to the AC unit and not to the iZone system itself. (For iZone system faults, refer to the Messages section.)

Each AC unit fault entry is date- and time-stamped for future reference.

If a fault occurs, it is recommended that a qualified technician connects the proprietary AC unit controller to verify the fault and obtain the specific fault code.

The AC unit fault history cannot be deleted, edited, or reset.

Filter Inspection

The iZone system will display a reminder message prompting the user to clean their filters.

This function operates purely on a time-based schedule, and resetting the message will also reset the timer.

It is recommended to choose a reminder frequency that best suits the specific site conditions.

Available alert intervals for filter cleaning reminders are:

Disabled (no reminder displayed)

• 3 months
• 6 months
• 12 months

Lock Temp

When enabled, this option locks the minimum and maximum set point temperatures that users can select across all zones and, if applicable, the AC unit control.

It is recommended to use this option together with the Max SP Temp and Min SP Temp settings.

Max SP Temp

In this option, the technician can set the maximum temperature that the user is allowed to increase the set point to.

After setting the limit, the technician must activate "Lock Temps" for the restriction to take effect.

Min SP Temp

In this option, the technician can set the minimum temperature that the user is allowed to decrease the set point to.

After setting the limit, the technician must activate "Lock Temps" for the restriction to take effect.

Scrooge

Scrooge is effectively a placebo effect

When the Scrooge mode is selected it will utilise the Max SP temp and Min SP temp settings to limit the operation of the system between these two values, however, the user will still be able to select the full range on the iZone screen. When in this mode the Actual temp is hidden on the touch screen

Make sure "Lock Temps" is deactivated when Scrooge is activated to ensure it works correctly

Hide Actual Temp

To minimize customer inquiries and unnecessary analysis, you can choose to hide the system’s actual temperatures by enabling the "Hide Actual Temp" option.

Select this option if you prefer not to display the actual temperatures on the screen or app.

Hide In-Duct Temp

To minimize customer inquiries and unnecessary analysis, you can choose to hide the system’s In-Duct temperature by enabling the "Hide In-Duct Temp" option.

Select this option if you prefer not to display the In-Duct temperature on the screen or app.

Airflow / Temp

On the Modern Graphics Display → Zone Summary, you can choose to show either the Airflow Percentage or the Actual Temperature for each zone.

If this option is not selected, the Zone Summary will display the Airflow Percentage for each zone.

If this option is selected, the Zone Summary will display the Actual Temperature in each zone.

Damper Timing

Damper timing refers to the time it takes for a damper to move from fully open to fully closed. The iZone system uses this timing to accurately position the damper blades for percentage-based control and to detect damper motor faults.

By default, damper timing is set to Auto, which works well with iZone damper motors and other motors whose current draw can be detected by the system. During initialization in Auto timing mode, the system drives each damper fully open and closed to record the exact drive time for each actuator. These recorded times are then used for precise control and fault detection.

However, if the damper motor’s current draw is too low for detection (such as with Belimo actuators), the technician must manually enter the damper timing in seconds. When manual timing is used, damper fault detection is disabled.

Note that manual damper timing applies globally to all damper motors in the system, so it’s not recommended to mix actuators with different drive times on the same iZone system.

Reverse Dampers

The iZone system is designed to control iZone damper actuators (CZDA) and iZone cables (CDC12G), which operate the dampers from Open to Closed in a clockwise direction by default.

If you are using dampers that close in an anti-clockwise direction, the “Reverse Dampers” option should be enabled.

This setting applies globally, so when activated, all dampers in the system will operate in the anti-clockwise direction.

Open Dampers When AC Off

By default, an integrated iZone/AC system closes all zone dampers when the AC unit is turned off.

However, in some cases-such as heat exchange or ventilation systems that use the AC ductwork to distribute fresh air-it may be preferable for the dampers to open when the AC is turned off.

Select this option to have the dampers fully open whenever the AC system is switched off.

Skip Zone Ports

This option enables the technician to skip a specific zone port on the screen. It is especially useful if a zone port on the C225 or CEXT has been damaged, allowing that port to be bypassed and subsequent zones to shift by one port.

This function requires that spare ports are available. To use, select this option from the system configuration menu and then choose the zone ports you wish to skip.

Zone Damper Status

This option displays the status of all zone dampers in the system.

Damper statuses are shown as follows:

• OK: The zone damper is operating correctly.
• Not detected: The iZone system could not detect a zone motor connected to this port, or there is a fault with the zone motor, cable, or port.

Lock Zone Names

When this option is enabled, zone names will be locked and cannot be edited on the Zone Summary screen.

To rename zones, simply disable this option in Configuration → Options, allowing zone names to be changed.

System Lockout

When this option is selected a message will appear on the screen asking for a "lockout code"

Warning: If the lockout code is forgotten, the C225 will need to be reprogrammed at the factory.

The user sets their own lockout code (PIN).

The user will be prompted to enter the lockout code and specify the number of days the system can operate normally before the lockout activates.

Enter the desired number of days. To lock out immediately, enter 0 days.

When lockout is active, the AC system will turn off and the wall controller is locked, and any attempt to make changes will trigger a pop-up requesting the lockout code.

Once the correct code is entered, the system will unlock and return to normal operation.

Lock Min Airflow

When enabled, this option locks the Minimum airflow setting at its current value.

Users can still adjust the Maximum airflow and view the Minimum airflow setting, but will be prevented from changing the Minimum airflow.

Sensor LED Options

Wireless Sensor

The wireless sensor LED has three display modes designed to conserve battery life:

• Blue LED: Lights for 2 seconds when the sensor button is pressed and the zone is set to Climate control.
• Red LED: Lights for 2 seconds when the sensor button is pressed and the zone is Closed.
• Blue and Red Flashing: Flashes for 2 seconds when the sensor is not receiving confirmation from a paired C225 module.

Wired Sensor

The wired iZone sensor LED offers two configurable display options:

• LED ON Option: Blue light remains on whenever the zone is in Climate Control or Open; turns off when the zone is Closed.
• LED OFF Option: Blue light flashes for 2 seconds when the sensor button is pressed and the zone is in Climate control; remains off at all other times.

Ventilation System Control

The ventilation system can be managed using air quality sensors integrated into the Nexus+ touchscreen. It can automatically adjust fan speed based on detected contaminant levels. Multiple sensors may control the system, and unselected sensors will not affect it.

Sensor control parameters:

• Relative Humidity (RH): Fan speed adjusts to maintain RH within set point (SP) ± 5%. SP range: 5% to 95%.
• Volatile Organic Compounds (VOC): Fan speed adjusts to maintain VOC within SP ± 50 ppb. SP range: 50 to 2500 ppb.
• Carbon Dioxide (CO2): Fan speed adjusts to maintain CO2 within SP ± 100 ppm. SP range: 500 to 1500 ppm.

Time Delay Between Stages (Minutes): A delay between fan speed changes can be set to prevent excessive cycling. Default is 3 minutes; adjustable between 3 and 240 minutes. This delay applies universally to all stages and sensors.

Cycle Fan Off:

• If selected, the fan will turn off once all monitored parameters stay below their set points for the specified delay time.
• If not selected, the fan will run continuously at low speed to provide minimum ventilation.

Advanced Electronic Constant Control

Advanced electronic constant control offers more precise management of constant zones, especially beneficial when only one or two small zones are non-constant. To configure this system, the area of each zone must be input along with a minimum area that must always remain open-referred to as the “Area to be covered by constant.” This value is typically calculated as three times the capacity of the AC unit.

For calculation purposes, the iZone system assumes that a zone open to 80% is supplying 80% of its airflow. For example, an 18m² zone at 80% open is considered to be providing airflow equivalent to 14.4m² (18 × 0.8).

Example: For a 14KW ac with 6 zones,

Zone	Area (m²)	Percent Open (%)	Equivalent Area (m²)
Zone 1	13	20	2.6
Zone 2	12	30	3.6
Zone 3	20	0	0
Zone 4	11	90	9.9
Zone 5	22	10	2.2
Zone 6	18	0	0
Total	96		18.3

In this example, the total equivalent active area is 18.3m². The minimum area that must be covered by the constant zone is 42m² (determined by the system designer).

Calculation: Required area to be served by the constant zone = 42 – 18.3 = 23.7m²

Percentage constant zone must open = 23.7 / 42 = 0.56 (or 56%)

Therefore, the constant zone will open approximately 56% to maintain the equivalent of 42m² of active airflow.

While this method isn’t perfectly precise, adjusting the reported areas of the zones and constant can help achieve a satisfactory balance.

Master / Slave

By default, the iZone system operates as the Master controller.

If a remote controller is connected and tries to change settings, the iZone system will override those changes and restore its own settings.

To allow external control, the Master/Slave option in the configuration settings can be customized.

This Master/Slave setting enables third-party controllers to manage certain air conditioning unit functions.

The control permissions for each function are as follows:

Function	Controlled by iZone	Controlled by Other Controllers
On/Off	●	○
Mode	●	●
Fan Speed	○	●
Set Point	●	○

Explanation:

• On/Off can only be controlled by iZone.
• Mode can be controlled by both iZone and other controllers.
• Fan speed can only be controlled by other controllers.
• Set point can only be controlled by iZone.