I have a Buderus G215/Riello 40 F5 with a Logimatic 2107 control. Sometime during the night my heating system shutdown. This morning when I looked at the Logimatic display, it showed a "HEATING ERR". I have a feeling air may have found its way into the line, I just recently filled my tank and the tanks was pretty close to empty. After a number of attempts at reseting the burner, it finally started. I placed the logimatic on manual and the aquastat was set near 180. At some point during the cold start the pressure breached the 30PSI Threshold and purged water through the check relief valve. I released some water from the system, relieved some pressure, switched the logimatic back to automatic, and now the pressure has been fairly steady at about 20PSI.
Question .... Can anyone provide some thoughts on why the pressure spiked to the 30 PSI mark? I'm not sure whether I should have reduced the aquastat when running in manual mode, or whether this is just a symptom of a cold start? I'm obviously a newbie ... Any thoughts?