Draught test on patio doors

[Leslie1091]

Can anyone help, I have had two pairs of patio doors fitted to my property, one set is 2350mm high x 2400 wide and a further set 2350 high x 1500 wide. I have reported to the suppliers that the doors are not meeting in the middle as they are bellying out. After several visit fitting heavier brushes between the closing edge, I am of the impression they are still letting in draughts.
yesterday I carried out a smoke test by lighting a smoke stick and placing in front of the area the problem is utmost, the reaction of the smoke confused me, you would have expected the smoke to rise but it done the opposite and went down toward the bottom of the door.
Can anyone tell me why this would be?

 

[footprints]

Perhaps because cold air (drafts) falls as opposed to hot that rises.

 

[Leslie1091]

Perhaps because cold air (drafts) falls as opposed to hot that rises.

As per my suspicion, they are still not performing.

 

[Diyisfun]

My doors had to be slammed to shut, I had the manufacturer back & they said they hadn't been installed correctly. They had to cut the seal, so I now get a draught, but I can shut the door as against slamming it.

 

[crank39]

Could be convection, as heat rises up the window it cools and falls to the bottom, the cycle then starts again, people instinctively put the back of their hand (because its highly sensitive) to the area they think is at fault and invariably think they feel a draught when in fact its just air movement

Put the back of your hand close to the double glazed unit and you can also feel the cold

 

[Gazman16]

Possibly either the frame or the door itself is not true.

Check with a large straight edge (preferably an 1800mm level) Check to see if they are straight both vertically and plumb.
Do you know the make of the doors?