issues with new zone

[goldenspacek]

I have a Lennox furnace with a 2 stage motor on it and the Harmony II zone controller.

I had a "professional" come out and put a 4th zone on my furnace to heat the area above the garage. He ran a 6" pipe up to 3 ducts (about 15' up and 15' across, one duct at each end and one around 8'). The other 3 zones are about 1500 sqft each, the garage zone is about 500 sqft.

Long story short, the heat gets there, but the entire main hose heats up to a bazillion degrees even when zone 4 is the only one calling. I have read that this zone may be too small (okay IS too small). So I tried setting the jumper switch to 25% for airflow for the 4th zone but that didn't do anything.

My questions are...

Is this ruining my furnace?

And should I try to have the guy come back to fix the zone, or should I just remove the zone and make it part of zone 1 or something. Of course I wouldn't be able to control the heat very well doing the ladder.

And last, why is the rest of the house heating up. It is like the other zones are opening.

Thank you in advace for your reply.

[BaldLoonie]

This zone consists of 1 6" pipe? Yes! Too small.

[beenthere]

The zone is small.
But the 6" feeding an 8" and 2 other supplies to this room is backwards.

This isn't the guy that did the original zoning is it.

If its not. call the company that did the original zoning to see if they will redo it for you.