If you don't keep it above 1800 RPM there is an alarm that will sound, it's not documented in my owners manual so the first time it happened there was a bit of panic. Called the dealer and he came out to check on it, that was when we both learned about the 1800 RPM requirement.
It seems from what I read here on TBN that the Massey 17xxe series regenerates a lot more often than most other makes. It also seems to like to start its regen cycle about the time you are done for the day.:laughing: