Weil - Gas Boiler Fan Startup / Shutdown Fan Problem

Jonn2018

Hi everyone Weil McLain HE-4 gas boiler. Seems on startup the boiler fan does not always come on yet the hot surface igniter glows and the gas valve opens and the boiler will keep firing. I have tested the blower motor out of the circuit and runs fine ever single time.

Other times on a good start up the blower will shut down on temp limit but the gas valve keeps sending gas for a 1-2 maybe three seconds. Then you get a slight flame roll out, then one -2, or 3 seconds everything does shut down.

The unit has a Hot surface ignitor and it has an S8910U1000 universal ignition module

Amy suggestions??? Some pics attached

Also, If you shut the boiler off in the middle of a cycle and turn it back on could that be causing the HSI to heat and boiler to fire...because I turned it back on? I would have assumed that would cause a full reset and start the purge cycle again.

Still that does not explain why the fan shuts off and the boiler gas valve keeps firing for a sec or two, and flame rollout occurs.

Jonn2018

Pics here