Return Grill Size For 3 Ton

Size and capacity of air return intake.

Return grill size for 3 ton. Measure and verify the grille is pulling the required airflow from the conditioned space after the job is completed and the system has started. If it s flex it s 700. The square root of 576 is 24. Multiply the lengths and widths of common filter grille sizes to calculate the square inches of each.

One additional diagnostic step to assure duct leakage and thermal duct loss is low. Search is the most efficient way to navigate the engineering toolbox. Return grill should be 24x24. Size the return grille and duct to remove 340 cfm from the pressure zone according to your favorite duct sizing method.

Always round up and we have a tonnage value of 2 5. Therefore your return air duct and grill size will be 24 by 24 inches. 48 000 btus is equal to 4 tons of air. You need 144 sq in per ton.

Engineering toolbox resources tools and basic information for engineering and design of technical applications. A 14 round pipe is equivalent to 750 cfm s. The size of the return air grill depends on the size of the forced air fan. 400 fpm is the median air speed for this calculation.

Note also the return air grille sizing formula at the top of the chart. As r mentioned 1 ton 400 cfm s. In order to determine the size of the tonnage you have simply divide 980 by 400 cfm per ton. If that 14 round return is all you have it is undersized for your unit.

Your return trunk should at least match your supply or even 10 20 percent larger. Some of the common sizes include 20 by 14 25 by 16 and 20 by 20. Doing this for this space will yield a tonnage of 2 45. Once you find one that meets or exceeds the above calculated needed number you can use it as your filter grille size.

12 000 btus per ton. Size and orientation of return grilles and supply registers june 15 2020 bryan orr 2 comments proper sizing and orientation of grilles registers and diffusers may seem like such a simple thing but it s an area where confusion and mistakes are commonly made. 4 ton unit x 144 square inches 576 squared. You have a 3 ton unit which is 1200 cfm s.

For the same 2 5 ton system with a filter grille the grille size would need to be what size asked rick we usually use a 20 x 20 for 2 5 ton said the tech 20 x 20 x 2 800 800 cfm well that s big enough for a 2 ton but a 20 x 25 may be a better choice.