Ever Tinkered with the Air Flow/Full Indicator on a Grasshopper Power Vac Hopper?

[MBDiagMan]

I have everything really ironed out on the new to me Grasshopper. The last thing is the air flow indicator. It is an airflow sensor of some sort inside a filtered disc that is actuated by air flow and closes a pair of contacts when airflow ceases which activate a piezo horn. This tells you that the hopper is full or that the hose is plugged, either situation the operator needs to know about.

I am getting voltage to the sensor, but it is not closing contacts when there is airflow. The darn thing costs $182 or I would just replace it.

Anyone know what's inside that disc to serve as an airflow sensor? If I can't fix it, I will just put a screen in it's place.

Thanks for any information or experience that you can share.
Larry

 

[MBDiagMan]

I fixed it, so I will post an explanation here in case someone searches for information in the future.

It was obviously not installed at the factory, so whoever did install it was evidently overwhelmed by four connections.

The system consists of a piezo electric horn that is polarity sensitive and an air switch with a normally closed (NC) and normally open(NO) contacts.

It was wired up with reverse polarity and wired to the NO instead of the NC contacts.

To wire one up properly, find the positive wire to the clutch and see that it goes to the red wire on the horn. Then connect the other wire from the clutch to the NC contact on the air switch, and connect the black wire from the horn to the common contact on the air switch.

I'm pleased to have mine working. I hope this helps someone else down the line.
Larry