Specifications
TMP Oil Furnaces – Furnace Manual
670-000-004/1010 9
3 Connect supply and return ducts (continued)
Duct sizing (continued)
Table 4 Typical duct sizing for systems not over 100 feet equivalent length – round or rectangular galvanized
Do not apply this table for duct systems over approximately 100 equivalent feet in length. For longer systems or systems
using other duct materials, refer to ACCA Manual D. Incorrectly sizing duct systems can result in unsafe or uncomfortable
operation.
Round
duct
diameter4567891012141618202224262830
(inches)xxxxxxxxxxxxxxxxx
45
4
444--------------
65
5
6544- ------------
100
6
865544- - - - -------
150
7
1297655544- -------
200
8
141198766544-------
250
9
181310987665544- - - - -
300
9
20151210987665544- - - -
400
10
2619151311109876655544-
500
12
322318151312119876665555
600
12
3828221815131210987766655
700
12
46322520171514111098777666
800
14
523628231917151311109887766
900
14
58 41 31 25 21 19 17 14 12 11 10 9 8 8 7 7 7
1000
16
64 45 34 28 23 20 18 15 13 11 10 9 9 8 8 7 7
1100
16
72 49 38 30 25 22 19 16 14 12 11 10 9 9 8 8 7
1200
16
- 544133272421171513121110 9 9 8 8
1300
16
- 58443529252218161412111010 9 9 8
1400
18
- 6347383127241916141312111010 9 9
1500
18
- 685140342925201715141212111010 9
1600
18
- 725443363027211816141312111110 9
1700
18
- - 58 45 38 32 28 23 19 17 15 14 13 12 11 10 10
1800
18
- - 61 48 40 34 29 24 20 17 16 14 13 12 11 11 10
1900
20
- - 64 51 42 35 31 25 21 18 16 15 14 13 12 11 11
2000
20
- - 68 53 44 37 32 26 22 19 17 15 14 13 12 12 11
2200
20
- - - 59 48 41 35 28 23 20 18 16 15 14 13 12 12
2400
22
- - - 64 52 44 38 30 25 22 19 17 16 15 14 13 12
2600
22
- - - 69 56 47 41 32 27 23 21 19 17 16 15 14 13
2800
22
----61514434292522201817151514
3000
22
----65544737302623211917161514
3500
24
-----635442342926232119181716
4000
26
-----726147393329262321201918
Typical duct sizing
(For approximately 0.10 inch w.c. in a typical residential installation of galvanized metal duct)
CFM
Rectangular duct equivalent sizes
Minimum width
(inches)
for duct heights
(inches)
of :