Warranty: (Details) - USD ($)	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Warranty cost and accrual information
Warranty accrual, beginning of period	$ 777,599	$ 701,456
Accrued expense for fiscal year	290,910	265,362
Warranty cost incurred for fiscal year	(189,608)	(189,219)
Warranty accrual, end of period	$ 878,901	$ 777,599