Browse Forums Heating, Cooling & Insulation Re: Aust Stand for Duct and Vent sizing 4Jan 30, 2009 5:33 pm Grandview 36 on Beautiful Bribie Site Start Dec 5th 2007 Projected completion May 12th 2008 NOPE Handover 24th June 2008 Moved in 11th July 2008 Wating on one final thing - Still - Oct 2009 Re: Aust Stand for Duct and Vent sizing 10May 25, 2009 9:42 pm Grandview 36 on Beautiful Bribie Site Start Dec 5th 2007 Projected completion May 12th 2008 NOPE Handover 24th June 2008 Moved in 11th July 2008 Wating on one final thing - Still - Oct 2009 Re: Aust Stand for Duct and Vent sizing 14May 28, 2009 12:50 pm My understanding was that the policeman (for lack of a better word) are the QBSA for the technical side of things. I have had some fantastic dealings with a couple of air con installers in Brissy, non more so than Snowdonia and Tony Redsell Air Con. I tried getting advice from AIRAH but they didn't return my phone calls. Oh to have my time over again Anne Grandview 36 on Beautiful Bribie Site Start Dec 5th 2007 Projected completion May 12th 2008 NOPE Handover 24th June 2008 Moved in 11th July 2008 Wating on one final thing - Still - Oct 2009 Re: Aust Stand for Duct and Vent sizing 15May 25, 2022 8:25 am This is a very old topic, however I am certain it is just as relevant today so thought I'd add an update for anyone who lands here later. I work in a related industry with a lot of crossover so thought I'd add some professional input. The installation requirements are basically State regulated, although some requirements are part of the BCA. My experience is strictly NSW, however the installation issues are probably very similar Australia-wide. System specification, design & installation forms part of air-conditioning trade training but real world conditions overtake optimal application of best-practice principles. Like all businesses, time & money are the real driving factors in the industry and these ultimately shape the quality of installations. The issues quoted by Dymonite69 are commonplace. Despite the license-holder for a particular business being trained often the guys actually doing the job are not and they simply make it up as they go along. Basics such as where to place outlets and the Return Air are often confused (part of this is the dynamics of heating & cooling are different but the system needs to do both usually) and some installers simply don't know how to do it or have received erroneous instruction from senior colleagues or their employers. In general terms outlets should be near windows on external walls which are opposite or at least as far away as practically possible from the door to the room. This is simple physics, the major temperature differential is usually near a window and the exit point for the air in the room is the door to the rest of the house - so the outlet goes near the window(s) to minimise the temperature differential and allow the air to fill the room as much as possible before exiting the door under the draw from the RA. In R/C installs the Return Air should be centrally placed and as low down as is practicable (close to the floor preferably) - this is because cool air falls so being drawn along the floor makes no practical difference, whereas in heat mode warm air rises so you don't want the airflow along the ceiling but down towards the floor. They should always be filtered as well, they are much bigger but then all airborne debris stops at the filter pad rather than being circulated through the ductwork. The Thermo/wall control should not be close to the RA as there is a zone of temperature difference around the inlet, it should be centrally placed in the largest common area which forms part of the Common Zone. This will allow it to sample the largest area of average temperature and hopefully achieve the best overall temperature balance through the house. Duct sizing, routing & connection are usually the biggest issue (after under-sizing of units for energy output & airflow) as this is really where the rubber meets the road. Because a lot of these systems are installed in ceiling spaces (especially as retrofits) the installers often shortcut this part of the job to make their lives easier, it's no fun having to lie on your face in fibreglass insulation etc so the path of least resistance is very attractive. Air has a lot of similarities to water so the same principles apply as in Hydrodynamic design, you need to manage pressure and flow to ensure even distribution with minimal restriction. In regards to Coljacqld's specific issues, I'd be very interested to know how her action through DFT & QBSA went. In my experience these organisations 'talk the talk' but definitely don't 'walk the walk' when it comes to enforcement of the Consumer Guarantees. Generally speaking if you aren't willing to undertake legal action yourself, you'll get very little traction if the business at fault resists or ignores the bureaucrats. 10https://www.homeone.com.au/member/coljacqld Re: Aust Stand for Duct and Vent sizing 16May 25, 2022 12:20 pm Greendragon I would agree with the most, but placing outlets is also of the question of the comfort, e.g. placing outlet over your working desk or over your bed can be a problem. What do you know about draught free aircon systems with smaller ducts such as Airsmart? Also, what is your view on using in ceiling hydronic systems for cooling instead of aircon? Sorry! I'm new to this forum and have made a mistake in my posting! I'm looking for a structural solution to a stand alone wooden pickets fence with no structural rail… 1 3299 DIY, Home Maintenance & Repair Hi everyone Question about Brevis gas heating undergound - was recently installed by previous owners (<1 year old) but live in a relatively large house - 4 bdr - and only… 0 2187 How do you remove one of these ceiling air con vents? And is it possible to disconnect the duct joined to the vent from inside the house, without going into the roof cavity? 0 5947 |