weil mclain model 78 will not start

_Tony_

Hello..and thank you in advance for any assistance. NYC. Oil Boiler weil mclain model 78. Power flame burner wcr 1. Maintenance and repair work done over the summer. New oil pump, blower motor, nozzle, electrodes, cad, honeywell oil burner control, transformer. Boiler ran no issues. Last few days. Burner control was tripped...recently an oil delivery was made. Thinking clog filter cleaned line filter and pump replaced nozzle. It continued to tripped control. Never around to see what actually tripped the circuit. Replaced the oil burner control honeywell. Worked ok...for a few times. Now..call for heat or hot water...sequence begins. Spark, blower motor, I hear pump valve gets activated...starts for about 15 sec..pressure drops to zero..hear pump going...systems shuts off. And its over..wil no longer start. Lucky is a warm day..