Is a plenum box needed for the supply side of AC or could metal Y’s be used? About 10’ from my handler is a plenium box that comes in with a big foil duct (maybe 16”) and exits the box at a right angle and exits with 3 different sized foil ducts (10”, 6” and 4”). Couldn’t i just use a Y into another Y to keep the air flow running straighter instead of a right angle and eliminate the box? I assume making right angles slows air flow. (The rooms with the 6” and 4” ducts don’t get as cool. I Was going to install in line booster fans for them too.). (Hawai’i so AC only, no heat).
So in open plenum systems is it just the AHU return fan sucking all the ambient air in the general direction of the AHU just more slowly than ducted returns?
Yes, open plenum systems are only ducted on the Supply through which the conditioned air is delivered to the occupied space. The Return side of the unit is open to the plenum above the ceiling grid and pulls air from the surrounding plenum space. This means that the HVAC equipment will need a filter on the unit directly at the return to filter the plenum air. Because the Return side of the unit is open to the general air space in the plenum, the air velocity near the HVAC equipment will be lower than the velocity traveling through Return ductwork. However having the Return open to the plenum space rather than ducted means the motor will work against lower ESP than a ducted Return system. For additional questions on this topic contact specialtyprod@titus-hvac.com.
Thank you for a simple and easy to understand explanation.
Is a plenum box needed for the supply side of AC or could metal Y’s be used? About 10’ from my handler is a plenium box that comes in with a big foil duct (maybe 16”) and exits the box at a right angle and exits with 3 different sized foil ducts (10”, 6” and 4”). Couldn’t i just use a Y into another Y to keep the air flow running straighter instead of a right angle and eliminate the box? I assume making right angles slows air flow. (The rooms with the 6” and 4” ducts don’t get as cool. I Was going to install in line booster fans for them too.). (Hawai’i so AC only, no heat).
You do such a great job thank you so much
So in open plenum systems is it just the AHU return fan sucking all the ambient air in the general direction of the AHU just more slowly than ducted returns?
Yes, open plenum systems are only ducted on the Supply through which the conditioned air is delivered to the occupied space. The Return side of the unit is open to the plenum above the ceiling grid and pulls air from the surrounding plenum space. This means that the HVAC equipment will need a filter on the unit directly at the return to filter the plenum air. Because the Return side of the unit is open to the general air space in the plenum, the air velocity near the HVAC equipment will be lower than the velocity traveling through Return ductwork. However having the Return open to the plenum space rather than ducted means the motor will work against lower ESP than a ducted Return system.
For additional questions on this topic contact specialtyprod@titus-hvac.com.
@@TitusHVAC thank you so much 🙏
Thanks !
Thank you for this
Good explanation
Thank you!
good video!!
I’m listening with a set of headphones and it sounds like you need a drink of water baaaad!!
her voice distracts me lol
I'm confused why it's called plenum return if there's no plenum box
It is more accurately called a ‘ceiling plenum return’ because the ceiling space serves as a plenum to channel return air back to the air handler.
@@TitusHVAC
Is plenum return and return plenum synonymous?
I know it as "Open Return" rather than plenum return.
Nice!!!