JBJ chiller not working

[thedirtboys]

I have a JBJ mini arctica 1/15 hp chiller (it doesn't have the newer digital control, just the older dial) that has stopped working. Water runs through it fine but when it comes time for it to start cooling water the red alarm light comes on. I've tried running fresh water in reverse to flush anything out to no avail. Other than that, I haven't tried anything else because I have no idea what to try. Any suggestions?