Questions about re-routing ducts in ceiling. Please help!

xe0s

I am by no means an expert, or even amateur HVAC person but I think I have a basic understanding of how air flows.

My question can best be described in the pictures below. The 1st picture is how the ducts are currently routed in the ceiling of our house. The 2nd picture is my idea on how to correct the airflow / push more air to the upstairs office which becomes incredibly hot during the day. The only way to keep the temp. at a comfortable level (72-74 degrees) in this room is to keep the AC set on 70-71 degrees... thus making the downstairs too cold. The thermostat is downstairs in the living room. The vents downstairs blow incredibly hard when the system is on, while the vent in the office barely puffs out air. I would like to try and correct this problem myself as I simply cannot afford to have an HVAC crew come out and charge me $500 to redo the ducting. If the AC is set on a normal temp. downstairs (73-74) the office easily reaches temps of 80-82 degrees.

Any help or insight yall could provide would be GREATLY appreciated!

Current layout of ducting in ceiling.


Idea for re-routing ducts to force more air to the office upstairs.

coolmen

the origenal layout where it goes 6" to a tee then 2 pc of 6" was a screw up at the begining The 6" should have been at least a 8" then tee to 2 pc OF 6" one 8 " = two 6". Your plan could work as long as things arent to long and install dampers at the plenum to ALL the take off suppplys

xe0s

Thanks for the advice!

I was also wondering if at the new 'off-shoot' from the 10" duct, would there be any harm in using a 10"x8"x8" wye duct? 10" coming from the plenum, then one 8" leading to the office and the other 8" stepped back up to 10" to meet the existing run to the downstairs?

coolmen

whats the `10" feding ? feeding the first floor wi a/c only or is this heat and cooling? taking a 8" off the 10" will practicly take half the cfm from the first floor area.could be more problems

xe0s

The 10" feeds 2 of the 4 vents downstairs and does provide heating & cooling. In Texas the heater hardly ever gets used and as the system stands right now those 2 vents downstairs pump air out like jet engines. The goal would be to cut down on the airflow going downstairs while increasing airflow to the office. If the downstairs vents are open the whole way the system cools the lower part of the house so quickly that the system will come on for about 2-5 minutes max per cycle, then shut off again leaving the upstairs temps nearly unaffected.

I'm sure the ducting has to be routed incorrectly for the system thats installed. We recently replaced a 20+ year old unit with a new one and I get the feeling that the guys I paid thousands to do it failed to ensure the ducting was setup to handle the increase in airflow over the old unit.

coolmen

What Size A/c Do You Have ?

wsuswim147

Why not install an in-line fan into the 6" duct with the low pressure and see if that works first before completly re-routing the system?