I think every set up will run differently I do play with my timer settings because I am always trying different fuel types and mixtures for the most part mine runs around 4.5 on and 7 off but when temps dropped i changed to 6on and 5 off and my boiler temps only dropped maybe 6-7 degrees. Biggest drop is when my 1800sqft basement slab kicks in it only runs maybe once every day or so. I'm thinking of putting in a mixing valve on that circuit that will remove the major shock load. My low burn timer is set at like 2 on and 12 off. Just remember if you play with your timers make small adjustments and wait some people get to jumpy and are constantly changing the timers and never allow the boiler to settle in on the adjustments. Once you know how your boiler is going to react you can change the timers according to the weather. Set it and forget it.My brother hasn't changed his all year.