This is the info (email) on differences between Class L and M Festool Midi extractor-
If an M class extractor is required then an L class will not officially suite.
We cannot recommend the use of a L class if you require M class extraction, but the bags, filter and motor are the same in an L and M machine.
The M has the alarm to basically tell you if airflow is reduced to a level that is too low, that is a requirement of an M class machine.
Regards
Customer services.
I've heard also from Festool customer services that the L is ok for example MDF, hardwood and other class M dust. Maybe if you regularly clean filter in L class it's fine for M class dust?
If an M class extractor is required then an L class will not officially suite.
We cannot recommend the use of a L class if you require M class extraction, but the bags, filter and motor are the same in an L and M machine.
The M has the alarm to basically tell you if airflow is reduced to a level that is too low, that is a requirement of an M class machine.
Regards
Customer services.
I've heard also from Festool customer services that the L is ok for example MDF, hardwood and other class M dust. Maybe if you regularly clean filter in L class it's fine for M class dust?