Before you begin
CAUTION
- Risk of property damage.
- Do not set the switch lower than the factory setting. The switch is factory set at approximately the minimum flow rate. A lower setting may result in the switch failing to return to a no-flow position which may result in damage to the controlled equipment or other property.
ATTENTION
- Risque de dégâts matériels.
- Ne pas régler le commutateur sur une valeur inférieure au paramètre d'usine. Le commutateur est réglé en usine sur une valeur correspondant environ au débit minimum. Un réglage sur une valeur inférieure risque d'empêcher le commutateur de revenir sur une position « aucun-débit », ce qui risque d'endommager l'équipement contrôlé ou de provoquer d'autres dégâts matériels.
CAUTION
- Risk of property damage.
- Do not attempt to change sealed settings (screws marked with black paint). Attempted adjustment may damage the switch or cause loss of calibration or other property damage.
ATTENTION
- Risque de dégâts matériels.
- Ne pas essayer de modifier la position des éléments de réglage bloqués (vis identifiées par de la peinture noire). Toute tentative de réglage risque d'endommager le dispositif de contrôle ou de provoquer la perte des valeurs d'étalonnage ou d'autres dégâts matériels.
About this task
The following table shows airflow velocities in fpm required to activate the switch for any given duct size, with horizontal or vertical upward flow. The flow rate table is based on a standard air density of 0.075 lb/ft3 (1.2 kg/m3).
| Paddle width | Switch actuation on flow | Minimum air velocity required to activate control | |||
|---|---|---|---|---|---|
| Horizontal flow | Vertical flow | ||||
| 50 in.2 (323 cm2) or larger duct area | Less than 50 in.2 (323 cm2) duct area | 50 in.2 (323 cm2) or larger duct area | Less than 50 in.2 (323 cm2) duct area | ||
| 2-1/8 in. |
Increase R to Y closes |
625 (3.2) | 575 (2.9) | 950 (4.8) | 750 (3.8) |
|
Decrease R to B closes |
325 (1.7) | 220 (1.1) | 850 (4.3) | 575 (2.9) | |
| 3-1/8 in. |
Increase R to Y closes |
500 (2.5) | 350 (1.8) | 750 (3.8) | 500 (2.5) |
|
Decrease R to B closes |
250 (1.3) | 100 (0.5) | 650 (3.3) | 350 (1.8) | |
To adjust the setting of the flow switch, complete the following steps:
Procedure
-
Adjust the switch’s flow rate. For more information, see the following
figure.
- Turn the adjustment screw counterclockwise to lower the flow rate required to activate the switch.
- Turn the adjustment screw clockwise to raise the flow rate required to activate the switch.
Figure 1. Flow rate adjustment
Note: Do not lower the flow rate required to activate the switch unless it is set above the factory set flow rate.