Learn Positioner Calibration

Reply to inquiry about Axico Fan "Stall" problem (from Axico VPM fan end user July 2011)

The condition you described Axico Fan (Stall) could be related to positioner out of calibration and/or improper cable connection location on the positioner lever arm. Stall can also be associated with high resistance at the fan inlet or outlet.

Calibration: Honeywell Positioner (Standard)?

The correct method of static calibration for axico fans style blade modulation is as follows:

1. Identify and clearly mark at the blade root area = maximum, mid and minimum blade pitch.
2. Set signal to positioner at mid pitch 9psi/63pa.
3. Loosen the feedback cable set screw and move the nut assembly to approx. 1.25 on the lever scale and tighten nut at that point.
4. Hold onto the lever firmly left hand (to pivot up or down) and at the same time with your right hand pull cable back and forth through the small lock hole.
5. When you have controlled the movement of the blades and they are at mid pitch angle, lock the set screw that holds the cable inside the hole.
6. Set signal to positioner at 15psi/105pa and check that maximum is reached.
7. Set signal to 9psi/63pa and check to see if mid is reached.
8. Set signal to 3psi/21pa and check to see if minimum is reached.
9. Repeat f, g, h a few times to confirm modulation has been calibrated.
10. There is a cam fine tuning adjustment wheel inside the positioner that can be used to fine tune the modulation of the blades. Just turn it in either direction and you'll notice small changes in blade pitch. Make sure the cam disc is tracking the cam roller wheel. You can also mark the cam wheel relative to pitch angle.
11. All of the above directions for positioner signal calibration are based on direct acting, if it's reverse acting 3psi/21pa = maximum, 9psi/63pa = Mid. 15psi/105pa = minimum.
12. If you have a stroboscope you can use it to freeze the blades and view positioner modulation while the fan is running. Water in the air can cause corrosion inside the diaphragm chamber. The rubber diaphragm can be cleaned but if the problem is serious you may find damage. Make sure your air dryer is working properly.

Q? Did you read the article on Learn About Axial Fans?

There are many issues with Axico fans so you may want to try and find an expert on that fan model in your area.

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