Latest update: So far for the entire month of May (through today, the 16th) our AHS S130 Coal Gun has only been eating 15.5 lbs. of coal per day on average. This lowers the bar on the minimum summertime daily average consumption of the S130 Coal Gun a bit. The only change I've made to the boiler for summer running is in dropping the SV of the thermo ash monitor (the ash grates motor control device) from 130 degrees to 120 degrees.
For the record, we took a 4 day vacation in May, and during those 4 consecutive days we had our oldest daughter come over daily to care for our chickens and also to run a single load of laundry through the washing machine (which was set on "hot") each day, so the boiler likely fired only once a day while we were on vacation due to this daily load of laundry. During our 4 vacation days there was no other daily DHW demand, such as from our typical showers, hand washed dishes, running the dishwasher, hand washing, shaving, etc... This no doubt contributed to the drop from 17.5 lbs. of coal daily to 15.5 lbs. daily.