check their website... sealandtechnology.com (i think) they have manuals on line.
it's usually pretty easy to troubleshoot... what are the symptoms ? pump cycling on and off every once in a while ? first listen for any hissing sound around the base of the head. if not, check hoses, clamps, along the way. if you dont' hear anything or see anything loose, you may want to replace the duckbills. how old are they ?