Ran into a fan issue. Check on boiler and I find the fan humming and just creeping along. Turn power switch off and back on and the fan goes into high speed and settles down into low speed like it should. I was finally in shed when aquastat turned back on and the fan just hummed and crept. Checked voltage at aquastat and a solid 110 going to fan. Talked to Dale at econoburn and he had me change a setting on the nimbus board. I got talking to him about the controls and he said the Aquastat is supposed to be used as a high temp safety shutoff not as a regular shutoff. I asked him if the fan is designed to be running all the time and he said yes except for the occasional high temp aquastat shut off. Basically the dip switch setting adjustment he told me to make, runs the fan slower on slow speed so it is more geared to maintaining temps rather than raising them. I still have a feeling I'm going to see the humming fan barely moving but I'll follow directions for now.