Fan cycle changed

ChazSnow

I'll try to make it brief. I picked up some water in my oil tank and it wouldn't fire. The system needed servi anyway. Because of the cost of fuel oil and I was bored I recorded the Burner and fan on/off times at different temperatures throughout the winter( yeah, I know I need a life)
So I pulled the tank filter and drained off the water, installed a new filter. Installed a new Cadcell and nozzle...Fires up great, Burner runtime is Identical to my recorded times 7 minutes +/-. BUT, my blower used to run, then off about 1m45s, then on for 30-40s, then final off. Now it only runs once, never a second time! I'm really interested in the efficiency aspect, what's happened to the residual heat? 

STEVEusaPA

Did you set up combustion/draft/smoke with proper combustion instruments?
Did you install the same size/angle/pattern nozzle?

It's possible you solved a problem of nozzle impingement on the heat exchanger causing after burn, allowing heat to rise and calling the blower motor to run as it should.

It's also possible you put in a smaller nozzle and therefore the heat exchanger doesn't retain any residual heat to call the blower to run again.

It's also possible the draft is wrong.

It's also possible you damaged the fan/limit switch.

Or, you may have improved airflow by changing a clogged air filter.

And it's even possible it works fine/better than it was before you touched it.

Can't tell from my computer, no benchmark to compare. But you really need a full combustion analysis performed to determine if it is actually running properly, as compared to a 'by eye' guess.

mattmia2

Did the blower stop while the burner was firing or did it run a second time after the burner shut off at the end of the heat call?