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5.2 DUCTING
Supply Air
For connection of supply ductwork directly to the unit, a duct collar must be mounted at the unit outlet. When
connecting ductwork to the unit, a canvas type connecting collar is recommended.
If a field fabricated plenum is used, canvas type connectors are recommended at the duct connection to the plenum.
Units are also available with a factory provided discharge plenum. Supply duct connections to the plenum
opening(s) should include a canvas type connector.
Return Air
The unit is designed for "free air returns". The minimum returns air temperature is 55°F (12.8°C). The equipment
room serves as the return air plenum.
If the return air is ducted to the unit, a flex connection must be supplied. Insulation for the return duct is
recommended. Only return air should be ducted to the unit. Outside air should not be brought into the return area.
Insulation
Insulate ductwork that passes through unconditioned space during cooling. Insulation should include a vapour
barrier to prevent absorption of moisture.
5.3 WATER PIPING
General
Due to the variety of piping practices, it is advisable to follow the recommendations of local authorities. They can
supply the installer with the proper building and safety codes required for a safe and proper installation. The water
piping should be installed with a minimum number of bends and elevation changes for best performance. Piping
should contain
1. Vibration eliminators to reduce vibration and noise transmission to the building.
2. Shutoff valves to isolate the unit from the piping system during unit servicing.
3. Manual or automatic air vent valves at the high points of the system.
4. Some means of maintaining adequate system water pressure (e.g., expansion tank or regulating valve).
5. Temperature and pressure indicators located at the unit to aid in servicing.
6. A strainer to remove foreign matter from the water before it enters the pump. It should be placed far enough
upstream to prevent cavitation at the pump inlet (consult pump manufacturer for recommendations). The use of a
strainer will prolong pump life and help maintain system performance.
7. A strainer with a #30 mesh or finer to remove foreign matter from the water before it enters the unit.
8. Size piping to minimize system pressure drop.
9. All piping must be supported independent of the unit.
10. To aid in service the unit should have a union in the water inlet and outlet water lines.
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