Midea V4 Plus S Series - Duct Connection; Specification to Flange and Bolt of Circular Metal Duct

MCAC-VTSM-2015-09 R410A All DC Inverter V4+S Series 60Hz
Installation 111
0.08”(2mm); when more than 11-13/16”(300mm), it is 0.12”(3mm). The permitted deviation of pipe end flatness
is 0.08”(2mm).
Discrepancy between two diagonal lines of rectangle duct shall not be more than 0.12”(3mm). Discrepancy
between two diameters of any cross-cut circular flange shall not be more than 0.08”(2mm).
6.2 Duct connection
1. Duct connection
1) The seam of duct board splice should be stagger and cross-seam is not allowed.
2) Specifications of metal duct flanges shall not be less than the data as shown in the table below.
Specification to flange and bolt of circular metal duct
Diameter of duct(D)
(in.(mm))
Specification of flange (in.(mm))
Specification of bolt
Flat steel
Angle steel
D≤5-33/64(140)
25/32×5/32(20×4)
-
M6
5-33/64(140)＜D≤11-1/32(280)
1×5/32(25×4)
-
11-1/32(280)＜D≤24-51/64(630)
-
1×1/8 (25×3)
24-51/64(630)＜D≤49-7/32(1250)
-
1-3/16×5/32(30×4)
M8
49-7/32(1250)＜D≤78-47/64(2000)
-
1-37/64×5/32(40×4)
Specifications to flanges and bolts of rectangle metal duct (mm)
Dimension of long edge of duct(b) (in.(mm))
Specification of flange(angle steel) (in.(mm))
Specification of bolt
b≤24-51/64(630)
1×1/8 (25×3)
M6
24-51/64(630)＜b≤59-1/16(1500)
1-3/16×1/8(30×3)
M8
59-1/16(1500)＜b≤98-27/64(2500)
1-37/64×5/32(40×4)
98-27/64(2500)＜b≤157-31/64(4000)
1-31/32×13/64(50×5)
M10
3) Diameter of bolt and rivet to duct flange for middle/low pressure system should be no more than
5-29/32”(150mm).
High pressure system ducts should be no more than 3-15/16”(100mm).
4) Four sides of rectangle duct flanges should be designed with screw hole.
5) If using reinforcement methods for duct flanges the corresponding specifications may be extended.
2. Connection of nonmetallic duct
Specifications of flanges should be in accordance with standard, gap of bolt hole should be no more than
4-23/32”(120m). Four sides of rectangle duct flanges should be designed with screw hole.
3. Strengthening of metal duct
When edge length of rectangle duct is more than 630mm, edge length of insulation duct is more than
31-1/2“(800mm) and length of pipe section is more than 49-7/32”(1250mm), or single-edge level area of low
pressure duct is more than 1.2 square meters and single-edge level area of high/middle pressure duct is more
than 1.0 square meter, strengthening measures should be taken.
4. Strengthening of nonmetallic duct
When diameter or edge length of HPVC duct is more than 19-11/16”(500mm), the joint section of duct and
flange should be equipped with strengthening board and the gap should not be more than 17-23/32”(450mm).
6.3 Main points for duct connections
1. Supporting, hanging and mounting brackets should be made of angle iron. Position of expansion bolt should
be correct, firm and reliable. The buried part could not be painted. Spacing should be in accordance with
regulations below:
1) If duct is installed horizontally, spacing should be no more than 13.1ft.(4m) when diameter or edge length is
less than or equal to 1.3ft.(400mm), while spacing should be no more than 9.8ft.(3m) when diameter or edge
length is more than 1.3ft.(400mm).
2) If duct is installed vertically, spacing should be no more than 13.1ft.(4m) and ensure there is at least 2 fixed
points on each straight pipe.