pure pro trio trouble

Hokie

I have a customer with a pure pro trio from webbs that is a direct vent setup,riello burner with pre and post purge board and the hydro level hydrosmart aquastat that will shut down and not restart unless the customer shuts either the emergency switch or the boiler switch off then back on(interrupting the voltage going to the boiler) its not going off on reset and the proper green lights on the control are lit. I have swapped out the riello primary control,the pre purge board and tried the start coil one by one and no change. I haven't been able to get to them while its off so cant try B1 on the aquastat to see if it is faulty because they flip a switch before I can get there. Any ideas what to look at? I am hoping they will leave it alone long enough for me to start testing voltages. The boiler was installed roughly 8 months ago but this all started last Saturday.