Proheat A4 - Manual (Page 27)

PROHEAT AIR A2/A4 INSTALLATION MANUAL 2-17
2.10 AIR DUCT INSTALLATION
General Considerations
• Use ducts and vents temperature rated for 300°F (150°C) with minimum
inside diameter of 2.95 inches (75 mm).
• DO NOT tap in to the vehicles OEM system.
• Avoid directing hot air from heater outlet vent within 12” (30 cm) or directly
at non temperature rated materials or people.
• Use the table below to determine maximum length of duct and maximum
number of bends.
• Use the fewest number of bends possible while ensuring there are no
airflow restrictions such as tight bends or kinks.
• Position inlet and outlet air ducts away from any obstructions and as far
apart as possible to prevent air short cycling (refer to figure 25).
2.10.1
MINIMUM
DIAMETER
3" (75 mm)
MAXIMUM LENGTH
394" (10 m)
Figure 24. Ducting.
Figure 25. Air Short Circuit.
INLET
OUTLET
INLET
OUTLET
Heater Duct Inside Total Duct Each 90° Maximum
Diameter Length Bend Bends
A2 2kW 3.0" (75 mm) 30 feet (9 m) 3 feet (1 m) 5
A4 4kW 3.0" (75 mm) 21 feet (6.4 m) 3 feet (1 m) 5
A4 4kW 3.5" (90mm) 30 feet (9 m) 3 feet (1 m) 5