AFA4000/1 Airflow Monitor / p.63
6.3.2.3 Chain and sprocket counterweight drive
In the Counterweight Drive arrangement, the chain and sprocket drive system is used to
directly lift the sash counterweight. This is achieved by fitting a roller chain to the
counterweight and utilising a separate counterweight and freewheeling sprocket to
maintain the correct chain tension.
Figure 36: Typical chain and sprocket counterweight drive installation
6.3.3 Installing the chain and sprocket counterweight drive
1. When the motor, chain and freewheeling sprocket has been fitted, manually open /
close the sash, to ensure that the motor drive is free running and that the chain is not
too slack or too tight.
2. Fit the motor so that the drive sprocket is in line with the counterweight pulley.
3. Fit one end of the chain to the counterweight or sash wire near to the counterweight.
4. Fit the freewheeling sprocket in line with the drive sprocket.
5. Loosely fit the chain over the freewheeling pulley and determine the best position for
the chain counterweight.
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