Johnson Controls YORK 120 Instrucciones página 12

Pulley adjustment and belt tensing (Models 90 - 300)
All units are equipped with single-speed motors and belt drives for fans. The variable pitch pulley of the fan motor can be adjusted to
achieve the desired impulse air flow. Belt tensing is to be carried out as shown in Fig. 1.
1.- Adjusting pulley opening (1 channel, mod. 090, 120, 150, 180 and 240) (2 channels, mod. 300).
- Loosen the belts by loosening nuts "A" and turning tension screw "B" (never loosen nuts "C").
- Loosen grub screws "D" to release mobile rims "E".
- Turn mobile rim "E" on the thread of the fixed core of the pulley in the adequate direction to increase or decrease the pulley opening.
- Tighten the grub screws, coinciding with their seating in the fixed hub of the pulley.
ATTENTION: On model 300, with a 2-channel pulley, both must have the same separation (the same amount of opening or closing turns).
2.- Belt tensing.
- Tense by means of tension screw "B".
- If no belt tension measuring device is available, use the following practical method:
- Apply a 5 kg. force on the mid-point of the belt, and perpendicular to same.
- With the application of this force, the belt should bend between 14 and 16 mm. for models 090, 120 and 150, and between 20 and 23
mm. for models 180, 240 and 300.
3.- After tensing, retighten nuts "A".
4.- It is recommendable to check tension twice during the first 24 hours of operation.
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Mod. 090, 120, 150, 180 and 240 (1-channel pulley)
Mod. 300 (2-channel pulley)
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Caution: Disconnect all power supply to the unit before starting any of these operations.
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Fig. 1
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Mod. 180, 240, 300
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