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Operation and Maintenance
Envistar Top 04-21
DSET.220501.07.en
Continuous product development may give rise to specification changes without notice.
6.9 Fan unit (code ELFF)
The purpose of the fans is to transport air through the system, i.e. the fan must
overcome the flow resistance in air terminals, air ducts and the unit.
The fan speed is regulated to provide correct air flow. If the fans generate a lo-
wer air flow, this will impair the function of the ventilation system.
•
If the supply air flow is too low, the system will be out of balance, causing
poor room climate.
•
If the extract air flow is too low, the ventilation capacity will be unsatisfactory.
Imbalance may also force moist air out into the building structure. One rea-
son why the fans are generating too little air flow may be that impurities have
collected on the fan impeller blades.
00020
1
2
3
Example fan unit size 04-06
00019
1
2
3
Example fan unit size 09-21
1. EC motor with control unit
2. Fan impeller
3. Vibration damper