Heating Help

How long to set prepurge?

Is there any reason for setting this shorter on longer. Seemed like 10 seconds would be plenty bring up to speed, but wondered if there might be reasons to have it more or less. Thank yuo

my experience

on commercial oil burners i have seen the pre-purge as long as 2 minutes.
on residential i have seen 4sec by using clean cut pump or about 10 sec on honeywell and on the genisys control you can set up to 30 sec(2 minutes on post- purge)
i think it all depends on the chimney. in the city where i am at some are over 100 yrs old and not in good shape. so with a longer pre-purge you can kind of create a better draft. also a lot most of the new boilers are set up for negative pressure over the fire,so by having a pre-purge you create a positive draft.
so the answer is use your own judgement on how good the chimney is or with new equipment use oem spec guide. i believe beckett tells you how long the pre-purge should be in there guide.

Thanks

Thanks, I tried 10 seconds and 15 seemed to give a better result and a smoother light.  Thanks again, that computer is a pretty slick item also since it shows runtime, etc,  Hard to believe the burner has lit 600 times in a week.  Its easy to forget how reliable the burners really are.