General Assist Technical Reference
UTZ-VXGA Fresh Air Intake Kit
Product compatibility, design requirements and installation guidance
For selected cassette-type indoor units
The UTZ-VXGA is a fresh-air intake accessory designed for compatible cassette indoor units. It can introduce outside air through one or two 100 mm duct connections, either using the indoor-unit fan or a separate duct fan.
Authorised personnel only: Installation must be completed by appropriately qualified personnel. Isolate power before installation and follow the indoor-unit, decorative-panel and UTZ-VXGA installation instructions.
1. Compatible indoor units
The UTZ-VXGA is listed for the following cassette indoor-unit models:
| RAC / PAC Models | VRF Models |
|---|---|
| AUTA30LBLU AUTA36LCLU AUTA45LCLU AUTA54LCLU | AUXD18LALH AUXD24LALH AUXA30LALH AUXA36LALH AUXA45LALH AUXA54LALH |
Compatibility check: Confirm the complete indoor-unit model and accessory compatibility before ordering or installing the kit. Similar-looking cassette models may use different accessories.
2. Product specifications
| Item | Specification |
|---|---|
| Model | UTZ-VXGA |
| Maximum fresh-air intake | Two-way intake: up to 10% of indoor-unit High airflow One-way intake: up to 5% of indoor-unit High airflow |
| Duct connections | Two x 100 mm diameter connections |
| Net dimensions | 120 x 840 x 840 mm (H x W x D) |
| Net weight | 5.5 kg |
| Inspection access | At least one 450 x 450 mm inspection hatch is required |
3. Design requirements and limitations
The UTZ-VXGA introduces untreated outside air into the cassette. The additional sensible and latent load must be included in the air-conditioning design and capacity calculations.
| 1 | Ventilation compliance: The kit may not provide enough outside air to satisfy applicable ventilation regulations. A dedicated ventilation or energy-recovery system may also be required. |
| 2 | Air volume: Keep intake airflow within the stated limit. Excessive outside air can increase noise, reduce capacity and affect room-temperature sensing. |
| 3 | Outside-air temperature: Do not introduce air below 0°C into the kit. |
| 4 | Condensation control: Fully insulate the kit and connected ductwork. Low outside-air temperature combined with high surrounding humidity can cause condensation. |
| 5 | Outside-air termination: Fit an external hood, weather protection, air filter and insect or animal screen. Grade external ductwork downwards at least 1:30 to prevent rainwater entry. |
| 6 | Separation: Position the outside-air intake at least three duct diameters away from other air intakes or exhaust outlets to reduce short-circuiting. |
4. Installation overview
Important: Installing the kit in the wrong orientation can cause water leakage. Align the kit's DRAIN and PIPE markings with the matching sides of the indoor unit.
- Prepare the indoor unit: Isolate the power. Where required, install outlet-sealing material before fitting the fresh-air kit.
- Protect the drain-pump tubing: Fit the supplied insulation around the protective tube, then refit the tube, clamps and binder.
- Set the installation height: For existing indoor units, adjust the indoor-unit installation height to approximately 230-235 mm from the ceiling as detailed in the manual.
- Prepare the kit: Install one or two duct flanges as required. Fit the shutter plate for one-way intake and apply all specified insulation without gaps.
- Attach the kit: Align the DRAIN and PIPE sides, provisionally position the kit and secure it to the indoor unit using the four supplied bolts.
- Install the hook plates and covers: Fit the four hook plates, transfer the drain cover from the decorative panel and apply the specified cover insulation.
- Replace the temperature sensor: Disconnect and remove the original room sensor from CN8, reinstall the empty sensor holder, then connect the sensor supplied with the fresh-air kit to CN8.
- Extend panel wiring: Fit the supplied louvre extension wires and, where used, the receiver-kit extension wire before reinstalling the control-box cover and decorative panel.
Ductwork requirements
- Use ducting sized to suit the 100 mm outside diameter of the supplied flange.
- Seal joints with bands and tape to prevent leakage at up to 200 Pa.
- Avoid sharp bends, repeated bends and reducing the duct diameter.
- Support T-pieces and ductwork independently so their weight is not transferred to the cassette or kit.
- Comply with applicable fire, non-combustible-duct and fire-damper requirements.
- Electrically isolate metallic duct materials where necessary to prevent short circuits.
- Use motorised dampers or shutters where cold air, strong wind or fog could enter while the system is stopped.
5. Optional duct fan control
A field-supplied duct fan may be operated in synchronisation with the indoor-unit fan using a field-supplied relay and the external-output wire included with the kit.
| System Type | Output / Relay Requirement | Maximum Extension |
|---|---|---|
| Single and Multi Split | CN6 output: DC 12 V ±2 V, permissible current 15 mA | 25 m from PCB to relay unit |
| VRF | CN16 output with field-supplied DC 12-24 V supply, permissible current 30 mA | 150 m from PCB to relay unit |
Do not power a duct fan directly from the indoor-unit output. The output is a low-current control signal and must operate a suitable field-supplied relay. Provide separate fan power and appropriate over-current protection.
6. Included components
The kit includes duct flanges, covers, screws, hook plates, a one-way shutter plate, insulation pieces, a drain-tube binder, louvre extension wires, a receiver extension wire, external-output wires and mounting bolts.
Final commissioning checks
Confirm the kit is correctly oriented and insulated, ductwork is supported and sealed, inspection access is available, the replacement temperature sensor is connected to CN8, the panel wiring is restored, airflow is within the permitted limit and no condensation or water leakage is present.
Confirm the kit is correctly oriented and insulated, ductwork is supported and sealed, inspection access is available, the replacement temperature sensor is connected to CN8, the panel wiring is restored, airflow is within the permitted limit and no condensation or water leakage is present.
This article is a summary for technical reference. The current installation manual, indoor-unit installation manual, decorative-panel instructions and applicable regulations take precedence.