Controller Model: HEG-DC02 (pictured), Author: Adam Hirst, version 01
HEG Air Circulation™ is a hybrid heat transfer system specifically optimised for the Tasmanian climate and market. HEG Air Circulation allows residential dwellings to:
- Have a healthier environment for residents due to improved air quality;
- Lower heating costs due to solar roof heat recovery & minimisation of secondary heaters;
- Achieve better distribution of warm or cool air around bedrooms & hallways;
HEG Air Circulation System Explained
The base system is comprised of a powerful air transfer system, called the HEG Air Circulation System. It is designed for long-term operation, often working 24/7 for 9 months per year during cooler months, with many customers keeping it in continual operation. The system continually circulates large volumes of warm or cool air to affect the remainder of the house. Whilst this circulation effect is occurring, solar gain through windows in rooms can be used to informally heat the rest of the house, resulting in very balanced air temperatures.
ABOVE: The standard living room ceiling inlet, at left, and a picture of the bedroom outlet, at right.
BELOW: A diagram showing the main thermal flows and features of a HEG Air Circulation System.
Other modules are added to provide functionality, as follows...
Roof Heat Recovery Module
Most systems are fitted with a Roof Heat Recovery Module (item 3 in the daigram, above), which is a filtered intake in the roof space which allows solar gain from the roof cavity to supplement traditional heaters in the household. The roof space intake has a motorised, filtered air valve that opens when the air in the roof space is over a specified trigger point. This trigger point, or temperature, can be adjusted by the customer, which is a useful thing to be able to do as requirements vary from house to house.
The image of the controller, at top of the first page, shows a temperature of 23 degrees in the roof space (NOTE: It does not show the room temperature). The trigger temperature is usually 20 degrees or above, which means that the Roof Heat Recovery Air Valve will open when the roof space air temperature reaches that temperature, or higher. When the roof heat recovery module is active (meaning that the roof heat recovery valve is open), you will notice a small red indicator light to the left of the temperature readout.
To turn the Roof Heat Recovery Module ON or OFF
Hold you finger on the power button on the thermostat for 3 seconds. When off, the temperature display will disappear.
To change the Trigger Temperature*
*This is the temperature when the Roof Heat Recovery filtered intake starts taking air from your roof cavity i.e. when a certain roof air temperature is attained.
Click the SET button, and then press the UP or DOWN arrows to adjust to the desired trigger temperature. To save the setting, simply leave the thermostat alone for 15 seconds and the screen will revert back to the temperature screen. Standard setting is 19 degrees.
Hint: hold you finger down on the SET button for 3 seconds if you don’t want to wait for the 15 seconds.
Condensation Control Module
This module allows drier, fresh air to be mixed and circulated with the internal air of your home. Outside air is generally quite a bit drier than internal air, so humidity levels are reduced due to dilution of moist air (and subsequent displacement of humid internal air out of cracks in the house structure). Filtered air is brought in via an intake on your eaves, gable ends or via a roof vent/cowl, whichever is most relevant to your house (depends on construction characteristics). The vents need to be cleaned monthly or more frequently when the system is in continual operation, and full instructions can be found here: www.heg.com.au/tabid/570/Default.aspx
Filtered Ceiling Inlet
Our usual ceiling inlets are usually a “Jet Diffuser” style, which is made up of rings of concentric circles. An optional extra is the filtered inlet, which stops dust particles from entering the system. These dust particles are already in your house, so it provides a degree of dust removal, similar to an air conditioning system. The filter cartridge can be accessed by hand unscrewing the bolt at one edge of the filtered intake. The filter needs to be cleaned frequently, and changed every two years.
- 24/7: Leave the system running all of the time during cooler months with the Roof Heat Recovery Module permanently on.
- Use the system without the Roof Heat Recovery Module during summer to duct cooler ventilation or cool air from air conditioners.
- The filter sock on the Roof Heat Recovery Module can be DIY cleaned once per year using a vacuum cleaner, but needs to be replaced every 2 years. See HEG for DIY or professional maintenance servicing.
- Filtered Inlet: The intake for the HEG Air Circulation System is usually a filtered grill, which has filter cartridge located just above the grill. This can get clogged with dust, hair and other particles over time. HEG suggests cleaning this monthly, or more regularly if a whistling sounds is present, indicating that the filter is becoming blocked.