This "reset" and "lockout" is a problem with the Suprima boilers and known about by potterton. It was featured on the bbc watchdog programme last year. The problem is the circuit board. I was unable to get mine replaced for free by potterton after sending them the template letter available on the watchdog web site, but was offerred a 12 month servicing contract for £300 to fix it. The circuit board costs £180 plus vat at my local plumbers merchant, so the extra money for fitting it and replacing a worn sensor as well was worth it. It fires up perfectly now!
MS, February 2008