AFA4000/E VAV Airflow Controller / p.74
7. When the motor, chain and counterweight are fitted manually open / close the sash to
ensure the motor drive, chain and counterweight are free running.
6.2.4 Wire and pulley drive
With the Wire and Pulley Drive, the pulley motor drives the sash wire and can accept both single
and dual sash wire systems. The motor assembly is fitted in line with the sash wires and uses
two guide pulleys and a drive pulley.
The pulley drive is ideal for new fume hoods but can be retro-fitted if a longer replacement sash
wire can be fitted.
Figure 37: Typical wire and pulley drive installation
6.2.4.1 Installing the wire and pulley drive
The motor assembly can be fitted horizontally or vertically on either side of the fume hood, as
follows:
1. Fit the motor assembly so that the guide pulleys are in line with the sash wire.
2. Run the sash wire over the first guide pulley, around the drive pulley and then over the final
guide pulley.
When the motor drive has been installed, open / close the sash to ensure that the sash can
travel freely.
6.3 Sash light curtain
The Sash Light Curtain consists of three main components and associated wiring: