VAV K Factor

[Midaho]

Have just started servicing large VAV systems. I am aware that the temperature in a zone drives open or closed the damper and the box monitors the pressure behind the damper to determine how much to open. I am also aware that K Factor is the reistance of the box and duct work right through to the registers. My questions are:

1. How do I calculate K factor
2. Do I need it.
3. What is meant by Series connection
4. What is meant by parrallel connection.
5. What is the right way to set up the fan within the box if there is already supply air. There are ceiling space intakes behind the fans.

Many thanks

[Brian_UK]

Can you give us some Names or model numbers?

[Midaho]

I was looking for basic principles of operation as I come across several types of unit. The one yesterday was a YorkVAV HFS 2000 R/E Rect R/E RH. Serial 2059 F if that will help.