Performed a heating pm on an oil boiler. Brushed and vacuumed. Replaced the oil filter, nozzle and strainer. Checked electrical connections and safeties. Performed a combustion test. 84% efficient. Drained the system and replaced the flo check. Filled the system and purged. After purging the system, noticed the pressure was still increasing. Valves off the autofeed and the pressure stopped increasing. Recommend replacing the auto feed.