AirCon Energy Saver (AES) Installation

Aircon Energy Saver

Aircon Energy Saver - InstallationBefore commencing installation of the Aircon Energy Saver (AES) please read the instructions. Installation should be carried out by a suitably qualified person.

The AirCon Energy Saver ‘Voltage Input Selection Switch’ should be positioned to correspond to the appropriate voltage being used. Two mounting holes can be found at the ends of the AirCon Energy Saver and the unit should be mounted securely either horizontally or vertically. The AirCon Energy Saver is not IP rated and as such should not be mounted outside in the path of rain.

The AirCon Energy Saver is capable of directly switching up to 10A resistive (2A Inductive) load, if the AirCon Energy Saver needs to switch a larger load than this then an auxiliary relay of suitable rating will be required.

Isolate electrical supply that feeds the ACU under conversion. Remove the cover of the ACU and locate the electrical connections for the AC mains input, the outdoor (compressor) unit and the indoor thermostat.

Basic Method of Connection

The older type of Air Conditioning Units (ACU), in
particular the window type, are controlled by a  simple bi-metallic temperature sensor and thermostat. These types of ACU should be connected as follows:

  1. Switch off the mains power to the ACU.
  2. Locate the thermostat control to the compressor and connect an ammeter in series.
  3. Switch on ACU and measure the current at the connector. If the peak current is below 10 amps then continue to fit the AirCon Energy Saver unit. If the current exceeds 10 amps peak then a relay must be used (see Relay Connection on page 5).
  4. Switch off ACU and interrupt the thermostat to compressor contactor wire as shown below.
  5. Connect the cut wire from the compressor to either side of the ‘Non Voltage Switched Terminal’ and the cut wire to the thermostat to the other side of the terminal.
  6. Connect the mains power to the AirCon Energy Saver unit and attach the cover.

Relay Connection

Should the current measured, at paragraph 3 of page 4, be above 10 amps resistive (2 amps inductive) then an auxiliary relay must be used compatible with the meas- ured AC current. The auxiliary relay should be fitted as follows:

  1. Switch off ACU and mount the auxiliary relay, protected by a suitable enclo-
    sure, securely within the ACU.
  2. Interrupt the thermostat to compressor wire as shown on page 4.
  3. Connect the cut wire from the thermostat to either side of the ‘Non Voltage Switched Terminal’. Connect the other side of the ‘Non Voltage Switched Ter- minal to the Auxiliary Relay coil.
  4. Connect the cut wire from the compressor contactor to the normally open ter- minal.
  5. Connect the mains power to the AirCon Energy Saver unit and attach the cover.

Modern Air Conditioning

By far the most common types of air conditioning units are the Split or Cassette
types. In general these types have a thermistor or bead type of room temperature sensor. These types of ACU’s should be connected as follows:

  1. Turn off the mains power to the ACU.
  2. Locate the ACU’s own RETURN AIR temperature sensor and its connection to the control circuit board. [NOTE-some air-conditioning control systems also have an evaporator coil temperature sensor which should be ignored]
  3. Unplug the RETURN AIR temperature sensor from the pins protruding from the circuit board.
  4. Using a meter, measure the electrical resistance of the RETURN AIR tem-
    perature sensor, noting its value ‘A’.
  5. Look up the nearest resistance value, corresponding to the room temperature
    and measured value ‘A’, on the Temperature/Resistance chart on page 7.
  6. Connect the selected electrical resistors across the AirCon Energy Saver Non Voltage Switched Terminals as diagram below.
  7. Using suitable wire, connect one side of the AirCon Energy Saver Non Voltage Switched Ter- minal to one of the RETURN AIR connections on the air-conditioning unit’s control board using a female push-fit connector.
  8. Using suitable wire, connect the other side of the AirCon Energy Saver control connection to one side of the air-conditioner’s RETURN AIR temperature sensor.
  9. Using suitable wire, connect the other side of the air-conditioner’s RETURN AIR temperature sensor to the air-conditioner’s control circuit board.
  10. Reposition the air-conditioner’s RETURN AIR temperature sensor and check the continuity of all electrical connections made in the above steps.
  11. Power up the air-conditioner and check the operation of the AES through two complete cycles, ensuring that:

The supply air temperature reduces to a minimum value, confirming that the com- pressor is operating correctly.

The Energy Saver detects a minimum supply air temperature, its relay energises to
open its contacts and present the additional electrical resistance to the air- conditioner’s own control.

Temperature/Resistance Chart

2.2kΩ 5.1kΩ 7.5kΩ 10kΩ 27kΩ
15°C 8.6 19.4 28.1 37.6 63.3
16°C 8.3 18.5 26.8 35.8 62.0
17°C 7.9 17.6 25.5 34.1 60.7
18°C 7.5 16.6 24.2 32.3 59.3
19°C 7.2 15.7 22.8 30.6 58.0
20°C 6.8 14.7 21.5 28.8 56.7
21°C 6.5 13.8 20.2 27.0 55.3
22°C 6.1 12.8 18.9 25.3 54.0
23°C 5.7 11.9 17.6 23.5 52.7
24°C 5.4 10.9 16.3 21.8 51.3
25°C 5.0 10.0 15.0 20.0 50.0
26°C 4.6 9.1 13.7 18.2 48.7
27°C 4.3 8.1 12.4 16.5 47.3
28°C 3.9 7.2 11.1 14.7 46.0
29°C 3.5 6.2 9.8 13.0 44.7
30°C 3.2 5.3 8.5 11.2 43.3
31°C 2.8 4.3 7.2 9.4 42.0
32°C 2.5 3.4 5.8 7.7 40.7

Location of AES Bead Sensor

Locate and uncoil AirCon Energy Saver sensor, this is a black cable with black bead at one end. Route the cable through the ACU unit into the discharge chamber (this is
inside the unit in the space between the fins and grill that blows air into the
room). Avoid where possible placing the sensor cable adjacent to any power cables and in locations that may interfere with replacing the cover.

Using a cable tie, fix the AirCon Energy Saver sensing bead located at the end of the sensor cable within the main air discharge stream of the ACU, ensuring that the sens- ing bead does not touch the coil or metal fins. The bead maybe located any-
where between 30mm & 300mm from the fins.

Note A Avoid locating the bead in a position where the air might be subject to a prior deflection due to the shape of the discharge air chamber.

Note B The location of the sensor is highly important, the bead sensor must de- tect the air from the ACU before it discharges from the unit.

Note C If the unit has automatic shut off grill blades care must be taken to avoid the sensor mounting restricting the action of the grille blades.

LED operation.

1.   0.5 sec ON ——–0.5 sec OFF

AES initial learning cycle (3 minutes) after power up or interruption.

2.    3.0 sec ON ——–0.2 sec OFF – Compressor ON (by Temp.)

Indicates the compressor is ON by temperature.

3.    3.0 sec ON ——–3.0 sec OFF – Compressor OFF (by Temp.)

Indicates the compressor is OFF by temperature.

4.    0.2 sec ON ——–0.2 sec OFF

Indicates disconnected or faulty sensor.

Operational Parameters

Power Supply110 – 240V AC Version
Power Consumption90ma max
Operational range-5°C to +31°C (23°F to 88°F)
Control relaySwitching capacity 10A AC (resistive) 2A AC (inductive)
Environmental0°C - 55°C (32°F - 131°F)
15% - 90% RH non-condensing


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