Zephyr ZRM-E36BS290, ZRM-E42BS290 manual Subtotal column 1 =

Duct pieces	Equivalent number				Total
	length x used		=
3-1/ 4” x 10”	1 Ft.	x (	)	=	Ft.
Rect.,
straight
7” Round,	1 Ft.	x (	)	=	Ft.
straight
8” Round,	1 Ft.	x (	)	=	Ft.
straight
3-1/ 4” x 10”	15 Ft.	x (	)	=	Ft.
Rect.900
elbow
3-1/ 4” x 10”	9 Ft.	x (	)	=	Ft.
Rect.450
elbow
3-1/ 4” x 10”	24 Ft.	x (	)	=	Ft.
Rect.900
flat elbow
3-1/ 4” x 10”	30 Ft.	x (	)	=	Ft.
Rect.
wall cap
with damper
3-1/ 4” x 10”	5 Ft.	x (	)	=	Ft.
Rect.to
6” round
transition
3-1/ 4” x 10”	20 Ft.	x (	)	=	Ft.
Rect.to
6” round
transition
900 elbow
6” Round,	15 Ft.	x (	)	=	Ft.
900 elbow
6” Round,	9 Ft.	x (	)	=	Ft.
450 elbow
	Subtotal column 1 =				Ft.

Maximum Duct Length: For satisfactory air movement, the total duct length of a 3 1/ 4” x 10” rectangular 6” or 7” diameter round duct should not exceed 100 equivalent feet.

Duct pieces	Equivalent number				Total
	length x used			=
6”- 8”Round	30 Ft.	x (	)	=	Ft.
wall cap
with damper
6”- 8” Round, 30 Ft.		x (	)	=	Ft.
roof cap
6” round to	1 Ft.	x (	)	=	Ft.
3-1/ 4” x 10”
rect.
transition
6” round to	16 Ft.	x (	)	=	Ft.
3-1/ 4” x 10”
rect.
transition
900 elbow
7” or 8”	15 Ft.	x (	)	=	Ft.
Round,
900 elbow
7” or 8”	9 Ft.	x (	)	=	Ft.
Round,
450 elbow
7” or 8”	30 Ft.	x (	)	=	Ft.
Round
wall cap
with damper
7” or 8”	30 Ft.	x (	)	=	Ft.
Round,
roof cap
7” round to	8 Ft.	x (	)	=	Ft.
3 1/ 4” x 10”
rect.
transition
7” round to	23 Ft.	x (	)	=	Ft.
3-1/ 4” x 10”
rect.
transition
900 elbow
	Subtotal column 2 =				Ft.
	Subtotal column 1 =				Ft.
	Total ductwork			=	Ft.