Ducted A/C questions

G'day All,
Im after some advice for the Daikin Ducted A/C unit we have installed. The specs are;
Outdoor unit: RZP145DV1 - 14.5kW Cool - 16kW heat
Indoor Unit: FDYP145DFV1

Not long after we bought this house (5 years old) I went and checked on the ducts as the air conditioner was not cooling effectively. I found that most of the ducts had been torn. I have no idea how as they are pretty tough. It seems to me that the whole installation was not done professionally. The way the ducts have been run seem to be not utilising the A/C to its fullest. The system has 5 zone motors to cut off supply to the 4 bedrooms and the office.

At the moment I have managed to temporarily repair them. Of the ones that were damaged, they only had one cut per duct. Only one duct is completely buggered and needs to be replaced. To repair I opened the duct, joined the silver inner together and duct taped, then pulled the insulation and outer plastic over the join.

Question 1: Is this an effective repair or should I purchase joiners to rectify this properly?

If you look at the floor plan that I have drawn there are red numbers. These correspond to the photos that I have attached. You can see that for some strange reason the vent on the right hand side of the lounge room comes from 3m away although the AC supply is right next to it. The 12" duct that splits off at photo 3 needs to be replaced as the duct does a near 90 degree turn as it is too short (see photo 3-1.jpg)

What I would like to do is add another vent down in the hallway that leads to the bathroom and laundry. That end of the house gets quite cool in winter and hot in summer. Im not interested in heating / cooling the bathroom and laundry, just the area around there. Im not sure how to go about it.

Question 2: How should I tee this off? Do I replace the junction above the 4 and have a 10" duct go to that end of the house and then tee back to 8" ducts for the new vent as well as the existing vent that the T was feeding (above 6). On suggestion to me was to cut in a new outlet from the AC blower. See photo 2. The distance from the the left to the right of the insulated bit is 260mm so I think I would be pushing it to fit a 10" duct in there.

I think this system can be improved some what, I just dont know how. I know that ducted AC is an art and I dont think this system was ever set up correctly. I dont mind spending some money to sort this system out as in the long run it should save me some money as the AC SHOULD be running more efficiently. I can easily do the work myself, just need some guidance.

I can add some more photos or detail in the floor plan if required.

Cheers
Steve

Floor Plan - http://i97.photobucket.com/albums/l2...CFloorplan.jpg
Photo 2 - http://i97.photobucket.com/albums/l223/ausyuppy/2.jpg
Photo 3 - http://i97.photobucket.com/albums/l223/ausyuppy/3.jpg
Photo 3-1 - http://i97.photobucket.com/albums/l223/ausyuppy/3-1.jpg
Photo 4 - http://i97.photobucket.com/albums/l223/ausyuppy/4.jpg
Photo 5 - http://i97.photobucket.com/albums/l223/ausyuppy/5.jpg
Photo 6 - http://i97.photobucket.com/albums/l223/ausyuppy/6.jpg


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