Nederman VAC 12/20 Manual De Instrucciones página 29

– Used belts: F=20 N (4.5 lbf)
5. Put back the motor side panel.
6. Put back the belt guard.
NOTE!
New belts are liable to stretch slightly within the first 50–100 hours of
use and are to be more tightly tensioned than used belts.
9.3 VAC 20: Temperature control
Perform the following temperature control inspection every 500 hours of
operation:
• Heat the thermal switch with a hot air pistol while the unit is running,
see Figure 10. Make sure the temperature control valve opens when the
temperature reaches about 80 °C (176 °F). A distinct change in sound at
this temperature means the valve is working properly. It is also possible to
open the valve by bridging the contacts with a screwdriver, see Figure 11.
• Units with anti surge control: See the anti surge control manual for more
information.
9.4 Start-up valve
Perform the following start-up valve inspection every 500 hours of operation:
• Check that the spring holds the valve closed when the unit is standing still.
• Check that the spring holds the valve closed when the motor is in Y-mode.
• Check that the valve is open when the motor is in D-mode.
9.5 Flow restrictor FR 160
Perform the following flow restrictor inspection every 500 hours of operation:
• Check that the flow restrictor is activated when the motor current tends to
exceed the nominal current. Observe the damper arm at varying air flows.
The variation must cover the range where the restrictor is activated. If
adjustments are necessary, see Section '9.5.1 Adjusting FR 160'.
9.5.1 Adjusting FR 160
Perform the following to adjust the FR160, see Figure 4:
1. Remove the protection cap, Item 5, covering the spring.
For fine adjustments: Loosen the screws, Item 7, to release the disc,
Item 8.
– Turn the disc clockwise to increase the air flow and motor load.
– Turn the disc anti-clockwise to decrease the air flow and motor load.
For coarse adjustments: Move the free end of the spring to the nearest
hole on the disc.
2. Measure the motor amperage to check the result adjustment. This
is usually made with a clamp ampere meter around one of the three
incoming phases to the motor start and control unit.
VAC 12/20 EN
29