Craftsman air compressor manual 921-152100 - Craftsman 3 gal. Air Compressor, 1 hp, Tank

SOURCE: Leaks air at the pressure switch

start your compressor and let it buid up pressure to turn off. then unplug from power.lossen the fill tube that goes from the pump to the tank. when you loosen it. if it leaks air then your check valve is bad and will have to be replaced.

SOURCE: check valve

I have replaced countless checkvalves that were stuck open due to debris produced/ejected by the compressor. Most frequent problem was carbon deposits due to wrong type of oil in compessor. The carbon deposits form inside head and discharge hose. All carbon must be cleaned from head and hose when new checkvalve is installed. Use synthetic oil in compressor to prevent carbon deposit. Leaky valves and gaskets in the pump will also casue problems because this greatly increases the air temp discharged from the compressor. I use checkvalves pruchased from www.grainger.com. and not the sears valve. Good Luck

SOURCE: I need a operating manual

Hi sydclar,

Copy and paste this web address into your browser and the document will open right up for you: >>>> http://www.managemylife.com/mmh/lis_pdf/OWNM/L0703335.pdf
Hope this helps. If it does, I'd appreciate a 4 thumbs up. Thanks,

Handie Andie

SOURCE: i have a Craftsman 5 gallon horizontal compressor

http://www.managemylife.com/mmh/owner_manuals/27698/CRAFTSMAN-Air-compressor-L0702368?brand_name_search=921-166360