An apparatus and {HEAD ~ method} for using {TAIL ~ a programmable variable speed motor} to indicate a clogged filter while providing a constant airflow acrcss a wide range of restrictions 
for using
An apparatus and { HEAD ~ method } for using { TAIL ~ a programmable variable speed motor } to indicate a clogged filter while providing a constant airflow acrcss a wide range of restrictions
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH