I have had a single instance of a Primaflow GPA25-6-130 circulating pump 'locking up'. This is a CPE series unit, with Auto function: it's 3 years old. The AC mains supply was present, all the display elements were lit (abnormal) and the pump wasn't running. There was no response to pressing the Mode switch. After switching the system off for about 5s and then restoring the mains supply, normal & full operation was restored: there have been no more glitches after 2 days running. I'd be interested to hear if anyone has had this or a similar issue with this pump type: thanks.