Commissioning; Introduction; Centrifugal Fan; Air Volume Setting - Dantherm DanX AF Series User Manual

4. COMMISSIONING

4. C ommissioni ng

4.1 Introduction

When working on air-handling unit always turn off the electricity on the main switch and
repair switch (complete shut) and secure for reconnection from unauthorized persons. Only
open the inspection doors when the unit is totally stopped and the fans have come to a
stand still. After switching off the unit the fan impeller will run for about 1 to 3 minutes before
stopping totally. The fan wheel must never be stopped by hand or with an object.
Commissioning, maintenance and repair work should only being carried out by trained
specialists or by people supervised by authorized staff. It is the responsibility of the fitter to
read and understand this guide and other given information.

4.2 Centrifugal fan

To commission the centrifugal fan for the first time, the following actions have to be taken:
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4.2.1 Air volume setting

If the measured air volume does not correspond to the type plate data, or when the
measured running current of the motor is too high, the fan transmission has to be changed.
After calculating the right pulley sizes the pulleys can be changed in the following way.
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Check if the transportation brackets have been removed.
Check by hand if the fan wheel is turning freely.
Check the duct system that all dampers are open.
Check if the duct system is clean and not blocked by any parts.
Start up the fan for a few seconds and check if the fan wheel turns in the right
direction (see arrow on fan casing). If this is not the case stop the unit, switch off the
main current and change two phases of the fan on the terminal strip.
Close all inspection doors start up the fans and measure the running current of the
motors. If the running current is higher than on the type plate of the motors stop the
unit and check the air volume.
Unscrew the two Allen screws (3) and pull off the pulley (2) by screwing one Allen
screw into the thread (4)
Remove the bush (1) from the fan shaft if the new pulley needs a different bush
Refit the new pulley
Check if both pulleys are in line and tight the belt.
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