Fan actual speed is opposite of set level

Hi all. 1 of my 8 fan controllers has started doing something weird.

The fan controller unit indicates low/medium/high as expected, and the SHAC log shows the requested percentage values being set correctly, yet the fan itself is spinning at the inverse speed. That is, when I set low speed (configured for 20%), the fan is spinning more like medium speed (configured for 60%), and vice versa. Setting discrete percentages across the entire range seems to indicate the physical speed starts around what-is-usually medium, drops to what-is-usually low, then back up to full speed - think of a U-curve, or even a J-curve maybe (it's hard to be certain which). This fan used to work fine, and setting high speed (100%) is working as usual.

I've tried turning off the entire C-Bus system via its dedicated breaker, resetting the thresholds in Toolkit, changing the number of configured speeds, and everything else I can think of, but it's still behaving this way.

Maybe it's a hardware problem ie. fried controller, or maybe one or more of the fan controller's capacitors are dead?

Has anyone seen this behaviour before? Thanks in advance for your assistance.

 

Hey,

I’m not an expert on the fan controllers, but I would say it is the dual speed control capacitor. It is possible the relays in the fan controller are sticking but it doesn’t sounds like that. The capacitors are the ones that would have come with the fan and if you pop the front off the C-Bus fan relay for that fan you will find one or two capacitors inside. I would replace them first before you look at anything more major in terms of failed components. I should say that if you aren’t an electrician it would be highly recommended you get one to do this as this is mains voltage equipment.

I would have said it was generally due to someone connecting the wrong leg of the capacitor to the wrong terminal in the relay, but if it was working and no one has touched it I would say it is the capacitors failing.

Link to installation manual for the relays: https://updates.clipsal.com/ClipsalOnline/Files/Brochures/W0001291.pdf

Edit - Manual link and recommendation to use electrician

 

Thanks @jboer for the reply and link to the installation manual.

I finally had a chance to look at the hardware today. Turns out the capacitor wires WERE reversed! I swapped them over, and it now works like a charm.

I was so sure it used to work fine previously, but clearly I'm mistaken - maybe I only ever ran the fan on high in that room?!

Anyway, thanks for the tips @jboer - next time I won't be so quick to rule out the obvious ;-)