Saturninus
Mechanical
- Feb 12, 2003
- 5
I have run across several supply and return fans where they fixed the inlet guide vanes. There are working terminal boxes, still, but the inlet vanes don't move.
They are fixed somewhat closed, most likely because if they were fixed wide open, this would overcool the zones. There is perimeter heat (no reheat in terminal boxes).
Here are my questions:
1. would it be wise to change out these inlet vanes and replace them with a VSD?
2. what is the effect of leaving these inlet vanes in the airstream? Are they cutting the fan motor power by pre-spinning the air? Or are they increasing the fan motor power by increasing the static pressure resistance that the fan has to overcome?
3. How would I model this?
In advance, I really appreciate any help.
They are fixed somewhat closed, most likely because if they were fixed wide open, this would overcool the zones. There is perimeter heat (no reheat in terminal boxes).
Here are my questions:
1. would it be wise to change out these inlet vanes and replace them with a VSD?
2. what is the effect of leaving these inlet vanes in the airstream? Are they cutting the fan motor power by pre-spinning the air? Or are they increasing the fan motor power by increasing the static pressure resistance that the fan has to overcome?
3. How would I model this?
In advance, I really appreciate any help.