Quick Reference -HVAC (Part-2)

November 17, 2020 7 Comments

A.C Capacity
Ton KW H.P
0.64 2.1 0.8
0.80 2.8 1
1.00 3.7 1.25
1.28 4.6 1.6
1.60 5.6 2
2.00 7.31 2.5
2.56 9.35 3.2
3.20 11.6 4
4.00 14.4 5
4.48 16.7 5.6
6.40 22.1 8
8.00 29.1 10
1TON= 1TON=3000 K.Cal/Hr
1TON=1200 BTU/Hr
1TON=3.516 KW
1TON=1.25 HP (VRV / VRF Only)
1TON=4.7 HP
1TON=12660 KJ/Hr

Split AC Copper Pipe Size (Blue Star)
A.C Capacity Suction Pipe Discharge Pipe (Liquid)
Up to 1 Ton 12.7mm (1/2″) 6.4mm (1/4″)
1 To 4 Ton 15.9mm (5/8″) 9.5mm (3/8″)
5 To 6 Ton 19.1mm (3/4″) 9.5mm (3/8″)
7 To 8 Ton 22.2mm (7/8″) 12.7mm (1/2″)
9 To 11 Ton 28.6mm (1 1/8″) 12.7mm (1/2″)
12 To 19 Ton 28.6mm (1 1/8″) 15.9mm (5/8″)
20 To 27Ton 34.9mm (1 3/8″) 19.1mm (3/4″)
28 To 42Ton 41.5mm (1 5/8″) 19.1mm (3/4″)
Normal Split A.C Copper Pipe Maximum Length = 15Meter
VRV System Copper Pipe Maximum Length = 150Meter

Split AC Copper Pipe Length
A.C Capacity Maximum Pipe Length Maximum Indoor & Outdoor Height Difference
0.5 Ton 15 Meter 5 Meter
0.6 Ton 15 Meter 5 Meter
0.75 Ton 15 Meter 5 Meter
1 Ton 20 Meter 10 Meter
1.5 Ton 25 Meter 10 Meter
2 Ton 25 Meter 10 Meter
2.5 Ton 30 Meter 10 Meter
3 Ton 30 Meter 20 Meter
3.5 Ton 30 Meter 20 Meter
4 Ton 30 Meter 20 Meter

Split AC Copper Pipe Additional Refrigerant Charge
Total Pipe Length 50 Meter 60 Meter 70 Meter
Additional Refrigerant None 250 gm (25gm/Meter) 500 gm (25gm/Meter)

Copper Pipe Thickness
Pipe Size Thickness Tube Gauge Type
6.4mm (1/4″) 0.8 mm 21 Soft
9.5mm (3/8″) 0.8 mm 21 Soft
12.7mm (1/2″) 0.8 mm 21 Soft
15.9mm (5/8″) 1 mm 19 Soft
19.1mm (3/4″) 1 mm 19 Soft
22.2mm (7/8″) 1 mm 19 Hard
28.6mm (1 1/8″) 1.2 mm 18 Hard
34.9mm (1 3/8″) 1.2 mm 18 Hard
41.5mm (1 5/8″) 1.3 mm 18 Hard
De-Oxidized Copper Tubes (DHP) , Copper 99.9%
Soft Copper as per ASTM B68
Hard Copper as per ASTM B75 / ASTM280 / BS 2871

Gas Pressure For any Ton Capacity
Refergerent Suction Pressure (PSI) Discharge Pressure (PSI) Standing Pressure (PSI)
M/C ON M/C ON M/C OFF
R 22 60 To 70 250To 300 156
R 32 120 490 260
R 134A 35 158 To 199 95
R 290 65 275 To 300 125
R 404A 87 270 To 356 190
R 407C 63 247 To 307 153
R 410A 110 To 120 400 To 500 250
R 417A 65 261 140
Nitrogen Pressure Test

Vacuum
3 Minutes 150 PSI <= 500 Micron for 24 Hours
5 Minutes 325 PSI
24 Hours 500 PSI
vacuum < 500 Micron

System Problems
System Problem Discharge Line Pressure Suction Line Pressure Suction Line Temperature Compressor Amp
Over Gas Charge High ↑ High ↑ Low ↓ (Ice on Suction Pipe) High ↑
Under Gas Charge Low ↓ Low ↓ High ↑ Low ↓
Capillary Block Low ↓ Low ↓ High ↑ Low ↓
Less Air Flow on Evaporator (Indoor Unit) Low ↓ Low ↓ Low ↓ Low ↓
Less Air Flow on Condenser (Outdoor Unit) High ↑ High ↑ High ↑ High ↑
Dirty Condenser (Outdoor Unit) High ↑ High ↑ High ↑ High ↑
Low Ambient Temperature Low ↓ Low ↓ Low ↓ Low ↓
High Ambient Temperature High ↑ High ↑ High ↑ High ↑
Insuffient Compressor Low ↓ High ↑ High ↑ Low ↓

Insulation Thickness
Refrigerant Pipe Insulation Drain Pipe Insulation
22.22mm To 28.58mm 19mm 25mm / 32mm /40mm 6mm
12.7mm To 19.05mm 13mm / 19mm
6.35mm To 9.2mm 9mm / 13mm

 Referent Pipe Insulation
Pipe Pipe size Insulation Type (EPDM or NBR)
Standard conditions 86°F (30°C), < 85% High humidity conditions(a) 86°F (30°C), >85%
Liquid Pipe 1/4″ (6.35 mm)  To 3/8″ (9.52 mm) 3/8″ (9 mm) 3/8″ (9 mm)
1/2″ (12.70 mm)  To  2″ (50.80 mm) 1/2″ (13 mm) 1/2″ (13 mm)
Vapor Pipe 1/4″ (6.35 mm) To 7/8″ (22.23)  1/2″ (13 mm) 3/4″ (19 mm)

The distance between the supports of the copper pipes.
Diameter Distance (m)
 ≤ 20 mm 1 Meter
20 To 40 mm 1.5 Meter
 ≥ 40 mm 2 Meter

The permitted length and drop difference
Pipe length Max. pipe length <= 240 Meter
Equivalent length from the first branch to the farthest indoor unit <= 40 Meter
Drop height Drop height between indoor unit and outdoor unit <= 110 Meter
Drop height between indoor units <= 30 Meter

Factory Fabricated

Duct Size Gauge of GI sheet
1 – 900 mm 26
901 -1200 mm 24
1201 -1800 mm 22
1801 – 2100 mm 20
2101 – above 18

Site   Fabricated
Duct Size Gauge of GI sheet
Upto 750mm 24
750mm- 1500 mm 22
1510 mm- 2250 mm 20
above 2250 mm 18

Horizontal Ductwork
Ducts Size Maximum Spacing
Area (m2) Diameter
less than 0.4 less than 125 mm 2.5 Meter
0.4 to 1 125 to 1000 mm 2 Meter
more than 1 more than 1000 mm 1.2 Meter

Vertical Ductwork
Ducts Type Maximum Spacing (Meter)
round 3.6 Meter
rectangular 3 Meter

Rectangular Duct Sheet Thickness as per CPWD
Longest side (mm) Minimum sheet thickness
Galvanized Sheet Steel (GSS) IS: 277  For Aluminum IS:737
750 mm and below 0.63mm (22 Gauge) 0.8mm  (20 Gauge)
751 mm to 1500 mm 0.8mm  (20 Gauge) 1mm  (18 Gauge)
1501 mm to 2250 mm 1mm  (18 Gauge) 1.5 mm (15 Gauge)
2251 mm & above 1.25mm   (16 Gauge) 1.8 (13 Gauge)

Round Duct Sheet Thickness as per CPWD
Longest side (mm) Minimum sheet thickness
Galvanized Sheet Steel (GSS) IS: 277  For Aluminum IS:737
150 mm to 500 mm 0.63mm (22 Gauge) 0.8mm  (20 Gauge)
501 mm to 750 mm 0.8mm  (20 Gauge) 1mm  (18 Gauge)
751 mm to 1000 mm 0.8mm  (20 Gauge) 1mm  (18 Gauge)
1001 mm to 1250 mm 1mm  (18 Gauge) 1.5 mm (15 Gauge)
1251 mm and above 1.25mm   (16 Gauge) 1.8 (13 Gauge)

DUCT Support OR Gripple Wire Support
Duct Size (mm)  Spacing (M)  Size of MS Angle (mm x mm) Size of Rod Dia (mm)
Up to 750 2.4 32x32x3 8
 751 to 1000 2 40x40x5 10
1000 to 1500 2 40x40x5 10
1501 to 2250 2  50x50x6 12
2251 to above 2  50x50x6 12

Round Duct Support
Round Duct Size (mm)  Spacing of Supports (m) Size of M.S. Angle (mm) Dia. of Hanger Rod (mm)
 Up to 500 1.5 40 x 40 x 6 12
 501 to 1200 1.5 40 x 40 x 6 12
1201 to 2250 1.5  50 x 50 x 6 15

Normal Ducting:
Larger duct-dimension  Spacing of Supports (m)  Sheet thickness, SWG (mm)
Up to 750 mm 1.5 To 2 2 24 G (0.63 mm) (25×25 GI flanges acceptable)
751 to 1500 mm 1.5 To 2 22 G (0.80 mm) (25x25x3 MS flanges  up to 1000mm; 40x40x5 MS flanges beyond 1000mm)
1501 mm to 2250 mm 1.5 To 2  20 G (1.00 mm) (40x40x5 MS flanges)
Above 2250 mm 1.5 To 2  18 G (1.20 mm) (50x50x6 MS flanges)

Supporting details for Low-Pressure system
LARGER SIDE OF DUCT mm SUPPORTING
ANGLE mm 		VERTICAL ROD
DIAMETER mm 		MAXIMUM
SPACING BETWEEN
SUPPORTS mm
Upto 900 40x40x6 10 3000
901 to 1500 50x50x6 10 3000
1501 to 2400 50x50x6 10 2400
2401 and above  65x65x6 12 2400

Supporting details for Round Duct
DUCT DIAMETER mm STRAP ROD
No WIDTH mm THICKNESS G No DIAMETER mm
Upto 600 1 25 22 1 7
601 to 900 1 25 20 1 10
901 to 1250 2 25 20 2 10
1251 t o1500 2 25 18 2 10
1501 to 2100 2 25 18 2 10

 Diffuser size
Area   Ceiling Height  Diffuser size(dia.)
Up to 12 sqmm 2.4 – 2.7m 200mm
Up to 12 sqmm 3m   250mm
Up to 20 sqmm 2.4m – 2.7m   250mm
Up to 20 sqmm 3m   300mm
Over 20 sqmm multiple diffusers

Additional refrigerant charged volume
Liquid pipe Size R410A (kg/m)
6.4 mm 0.022
9.5 mm 0.057
12.7 mm 0.11
15.9 mm 0.18
19.1 mm 0.26
22.2 mm 0.37
25.4 mm 0.45

Drain Pipe Capacity
Condensate water volume : V (L/h)=Indoor Unit (HP)x2  I.D (mm)  Thickness (mm)
V ≤ 14 Φ 25 3
14 ＜ V ≤ 88 Φ 30 3.5
88 ＜ V ≤ 175 Φ 40 4
175 ＜ V ≤ 334 Φ 50 4.5
334 ＜ V Φ 80 6
*If Slop is <1% than select next higher Size of Drain Pipe

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