PACi Overview

Panasonics packaged air conditioner range, PACi utilises a standard range of indoor units which can be used with a choice of PACi Standard outdoor units or PACi Elite high efficiency outdoor units and a common range of controls that they share with Panasonics ECOi and ECOG VRF systems.

Standard PACi systems are very energy efficient and meet all current legislation but are optimised for cost effectiveness and compact size. Elite PACi have been optimised for high performance and maximum energy efficiency.

To give you an example, take a 10KW high static ducted system with either a Standard PACi outdoor unit or its Elite equivalent and the differences are shown below -

 System Standard PACi Elite PACi
 Cooling Capacity 2.7KW to 11.5KW 3.3KW to 12.5KW
 Cooling SEER & Energy Rating 5.4 - A 5.8 - A++
 Heating Capacity 2.1KW to 13.8KW 4.1KW to 14.0KW
 Heating SCOP & Energy Rating 3.8 - A 3.8 - A
 Outdoor Unit Dim H x W x D 996 x 940 x 340 1,416 x 940 x 340
 Max Pipe Run / Lift 50m / 30m 75m / 30m
 Cooling outdoor operation range -10C to 43C -15C to 46C
 Heating outdoor operation range -15C to 24C -20C to 24C
 RRP* £2,453 £2,939

You can see from the above table that the Elite PACi has higher performance, better energy rating in cooling, can have a 50% longer pipe separation and has a wider operating range. On the other hand Standard PACi has a smaller outdoor unit and is significantly cheaper.

Having this choice allows you to make the right selection for your application.


All PACi systems use the same indoor units and controls - its just the outdoor units that change between Standard and Elite systems.

In Ceiling Cassettes - Compact - 3.6 to 5.0KW

These fit into a 600mm square ceiling tile and all of the mechanical parts are concealed within the false ceiling. They fit into a 290mm ceiling and are suitable for a fresh air duct connection. They have an inbuilt drain lift pump.

In Ceiling Cassettes - Standard - 3.6 to 14.0KW

These fit a  900mm ceiling opening and a 260mm (up to 7.1KW model) or 320mm (10.0KW model and above) high ceiling void. They have an innovative design ensuring 360 degree air flow and are suitable for either fresh air or branch ducts. They have an inbuilt drain lift pump.

Wall Mounted Indoor units - 3.6 to 10.0KW

These feature a flat washable front panel, good looks and high performance

Ceiling Suspended Indoor units - 3.6 to 14.0KW

These are very slim (only 235mm high) for applications where there is no ceiling void. They feature a fresh air duct connection on the rear.

Low Static Duct Indoor units - 3.6 to 14.0KW

These models are suitable for a slim 250mm ceiling void and are suitable for duct pressures up to 50 Pa. Please note these models do not feature a drain lift pump.

High Static Duct Indoor units - 3.6 to 14.0KW

These fit into a 290mm ceiling void and are suitable for 70 Pa (up to 7.1KW model) or 100Pa (10.0KW model and above) with a quiet and efficient dc fan motor. They have a built in drain lift pump. These have an innovative self commissioning fan feature to assist with set up.

Large ducted units - 20.0 to 25.0KW

These big units are suitable for up to 100m pipe separation and fit into a 500mm high ceiling void. These are only available with Elite PACi outdoor units.

Air Curtains - for 1m, 1.5m and 2.0m wide doors in 3m and 3.5m door height versions

Go here for more details

Twin, Triple and Quad Split Systems - 7.1 to 25.0KW

For rooms where better air distribution than with a standard split system is desired then we have the facility to connect 2, 3 or 4 indoor units to the same Standard or Elite PACi outdoor unit on the same controller.

You may have noticed that most indoor units are available in smaller capacities than the smallest PACi outdoor units and this is the reason why because these indoor units are used for TTQ applications.

A typical example would be an L shaped room with two 7.1KW cassettes connected to a single 14.0KW outdoor unit and a wired remote controller.

Floor, Chassis, 1way and 2way blow cassettes

It is possible for us to modify these ECOi indoor units in our workshop to work with a PACi outdoor unit for applications where something out of the ordinary is required.


Panasonic utilises the same highly flexible control system throughout their PACi and VRF product ranges so its easy to connect split systems with VRF all linked to a common BMS, central controller, web server or PC.

More details are shown here

As far as PACi is concerned the most common controller is the one shown above which is the CZ-RTC2. This is massively flexible and can control up to eight indoor units. It has a built in 7 day time clock, can control a ventilation fan or ERV connected to the indoor unit and has a simple, intuitive, operating interface. The things that an engineer can do with this controller are really something and you might want to have a look here at some of them.

Another popular option is the CZ-RE2C2 simple hotel wired controller. This is very easy to use and designed for hotel bedrooms but it still offers many of the same 'engineer' facilities as the standard wired remote.

A new option is a Wi-Fi controller that connects your PACi indoor unit to the internet and allows you to control it from a smartphone, tablet or PC. Or even from your TV using a web browser.

A brand new option is the touch panel CZ-RTC3 controller which looks great, has a blue backlit display and we believe it has greater functionality than the older RTC2 model described above. This has only just been released and is not backwards compatible with older systems and can only work with the very latest generation systems. But we will keep you posted as we get more experience with it. It also contains a power consumption monitor that is only used with PACi systems to help end users control their energy bills.

A big bonus is the ability of this controller to work with a separate Econavi sensor. This technology has been used for some years on the Etherea advanced RAC system and measures room occupancy and activity levels in order to modify the operation of the system. This has the potential to save a considerable amount of money and energy as the unit ramps down when there is low occupancy and low activity, only to ramp up again if either increase. It also can switch the unit off if the room is unoccupied for some time which will be a boon in offices and schools.

Another new controller is the new hotel controller. This is designed to be easier than ever to operate and promises a host of advanced features. We will let you know more as we get more experience with it.

As we understand it at this stage the controller has either stand alone, Modbus or LonWorks options and is available in either white or brushed aluminium. It not only controls the air conditioner but it also controls the lighting from the key card switch and is compatible with an Econavi motion sensor and optional window switch.

All PACi systems have the facility to be controlled by a wireless handset. Wall and compact cassette systems have a receiver built into them while the other cassettes and ceiling systems can have a sensor fitted to the grille or casing. All other models can be fitted with a remote receiver PCB . For servicing purposes we do suggest that you consider fitting a slave CZ-RTC2 wired controller or at very least keep one loose on site for an engineer to use when carrying out service or maintenance work or trouble shooting.


PACi systems use separate power supplies to the indoor and outdoor units. It is possible to take power to the indoor unit only or outdoor unit only and then take the power from indoors.

PACi systems have separate data cables to connect indoor to outdoor units, remote controllers to indoor units and also different systems to one another. These should be run in screened cable and run in separate cables to the power supplies.

Each PACi unit has terminals U1 and U2 which are for the main data bus and is used to connect the indoor to the outdoor unit and also between systems

Each PACi unit with a wired controller has terminals R1 and R2 to connect the controller to the indoor unit. You can connect up to two remote controllers to a single indoor unit or up to eight indoor units to a single or pair of controllers. You have to set up one controller as a master and one as a slave if you use two controllers together. Each unit with its own controller or set of up to eight units on the same controller is referred to as a group. Each outdoor unit with either one, two, three or four indoor units is referred to as a system.


If you link systems with a data cable then you should address each system separately before connecting them together. Addressing is done automatically but you must set each outdoor unit with its own refrigerant circuit (system) address and then run a self address on just the systems connected to this outdoor unit. Setting the refrigerant circuit (system) address is done using the 10s dip switch (S003) and 1s rotary switch (S002) on the outdoor PCB.

Performing a self address can be done at the controller but is also easy to do at the outdoor unit. Make sure that the power is off then put power onto those indoor units connected to the outdoor unit that you are setting up. Then power up the outdoor unit and connect across the jumper pins A-ADD (CN041) for four seconds. The two LEDs on the outdoor PCB will flash alternately for around five minutes and then turn off. You can then power everything down and perform the same address procedure for the next unit.

ALWAYS ensure that the refrigerant circuit (system) address is set on the outdoor unit and is different on each system. If different systems are connected by a controller (R1R2) but not by a data cable (U1U2) then you don't need to power down the other systems but if you do link systems with a data cable (U1U2) then you do.

You can initiate a self address at the controller as well. Press and hold SPANNER and TIMER UP for four seconds and AA will appear on the controller. Use the TEMP UP or DOWN buttons to select option code A1 and then use the UNIT button to select the system that you wish to auto address and press SET. That system will now self address, Repeat for all systems.

If you have problems with addressing then check the table below


Testing and setup

Once all of the systems have been addressed then you need to note down the address of each indoor unit. You can use the wired controller to confirm the address of each indoor unit. If you press SPANNER and VENTILATION together for four seconds then the controller will either show ALL or an address, a four figure option code setting and a two figure option code. If it shows an address then it will be in the form of two numbers, for example 1-1 which indicates indoor unit 1 on outdoor unit 1, or 2-3 meaning indoor unit 3 on outdoor unit 2. Also if the controller is showing an address then the indoor unit fan will operate. If instead of an address you get ALL then this indicates that the controller group contains more than one indoor unit so you will need to use the UNIT key to swap between indoor units. As you contact each indoor unit using the UNIT button then its address will be shown and the fan of that indoor unit will operate to show you which indoor unit is being operated. Exit this controller mode by pressing the SPANNER button.

You should make a full map of the system in this way, marking each indoor unit with its address using a permanent marker and leaving a complete map showing indoor units with addresses, outdoor units and controllers and how they connect together on site. You should also make a copy for your own use during service and maintenance.

Once the system has been mapped then you can use the SPANNER button on the controller or short circuit the  the CHECK pins (CN-CHK) on the outdoor unit you wish to test. To finish the check operation either press SPANNER again or remove the link from CN-CHK.

When you are operating the systems in test then you can press SPANNER and CANCEL for four seconds to check the readings one each temperature sensor. Use the UNIT button to swap between indoor units if you have a group controller. Use the TEMPERATURE UP and DOWN buttons to swap between sensors. Let the unit run for ten minutes and then record the readings of the sensors.

The important sensors are

  • 01 - Controller air temperature
  • 02 - Return air temperature
  • 03 - Indoor Coil entering temperature in cooling or leaving in heating
  • 04 - PACi only - Indoor Coil leaving temperature in cooling or entering in heating
  • 05 - VRF only - Indoor Coil leaving temperature in cooling or entering in heating
  • 06 - Air temperature leaving the indoor unit
  • 0A - Discharge temperature
  • 11 - Outdoor Air temperature

Outdoor Unit Service Controller

It is easy to use a wired controller connected to the outdoor unit PCB to take over a system, perform a self test and check all of the controller settings from one place. Details of how to do this are shown here