Don't bother, just pin them open.
I have a SWUA Trane package unit (40 tons) with airside Economizer and a water cooled condenser. I've recently added VFD control to the fan, and I'm considering removing the inlet vanes on the two fans. I've heard that you can increase the airflow from these units by doing this. Is this true? I don't want to spend the man hours removing the vanes and not get any results. Does anyone have any experience with this or had any luck by doing this?
Thanks
Don't bother, just pin them open.
SIRTAB is right. If you lose the drive you will have back up for volume control.
Good luck with the spare thing.Originally posted by weezer
SIRTAB is right. If you lose the drive you will have back up for volume control.
Just curious. How are you controlling the VFD reference.Originally posted by pincheal
I have a SWUA Trane package unit (40 tons) with airside Economizer and a water cooled condenser. I've recently added VFD control to the fan, and I'm considering removing the inlet vanes on the two fans. I've heard that you can increase the airflow from these units by doing this. Is this true? I don't want to spend the man hours removing the vanes and not get any results. Does anyone have any experience with this or had any luck by doing this?
Thanks
I was told that the vanes help guide the air into the vortex and removing the vanes will cause the blower to move less air at a higher blower amp draw due to turbulance thru the blower.
Thanks for the input, I was leaning towards the same direction. I can see where removing the vanes would cause turbulence and that makes sense to me.
As for the VFD reference, we have a DDC system that has a 0"-5" WC Pressure Sensor, that senses duct pressure, and maintains a user defined setpoint (usually around 1.25"WC) which then sends a 0-10vdc signal to our new ABB Freq.drives. We have on an average of 20-25zones per floor per unit, and when they are satisfied the pressure rises in the duct and the VFD slows, but it doesn't slow down to where we comprimise min. fresh air requirements for the entire floor. This system also incorporates a CO2 sensor that is linked to the economizer output (via software) and opens the economizer to lower the CO2 levels, but there are safeguards to eliminate the probability of bringing in too much OSA when it's too hot outside or too cold.
I can go on, but this post would be really long, the system is new and works really nice for our application.
Thanks again.
On the older boxcars you have to jumper out the end switch in the guide-vane damper motor. It would shut off the unit when the motor went to the closed position. The motor, if left hooked up electrically, will track the vfd through the original air pressure switches while the VFD if ramping the motor. Also, you will want to add the safety circuit (dry contacts)in the VFD to stop the cooling whenever there is a VFD shutdown. Wether it be for normal operation or safety. It normally requires its own relay unless the contacts are heavy enough to carry the normal control circuit for cooling. If you have heating, you will then need a two-pole relay unless the VFD has two sets of adequate dry contacts.
Good luck.