It's that time of year again - time to blow down the in-ground sprinkler lines to get as much water out of them as possible to prevent freezing and splitting, etc.
So, I trundled my Crafsman '6hp' (yeah, right ) 120v 25 gallon horizontal tank air compressor down the stairs to the basement shop and into the back storage room where the isolation valve and connection fitting to the sprinkler line is. Normally this compressor 'lives' up in the enclosed garage, and stays up there for things like filling tires, etc. I have a little Ridgid oil-lubed hot-dog compressor that I use down in the shop for things like nail guns, blowing out dust, etc.
Anyway... I plugged in the compressor and let it fire up (pressure in the tank was almost zero). It ran fine for a while... and then as it got around 95# or so, it tripped the breaker back at the panel. Well, I thought, it *was* plugged into the same outlet as the small chest freezer. I plugged the compressor into a different outlet on a different circuit via a heavy extension cord, and reset the breaker and turn the compressor back on. It ran for a while... and then tripped that circuit too.
I got to digging around, and thought to myself... 'I wonder if the stepson ever changed the oil in this thing like I asked him to'. Pulled the drain plug, and a depressingly small amount of oil came out into the drain cup. I went and found the 30W compressor oil, and filled and filled and filled and filled. I don't have the manual anymore (compressor is about 6 years old) and I've not been able to find one available for download from Sears as of yet. Anyway, I figured the bottom sump area has to be more than full by this point - pretty sure I put in about 4-5x as much as I took out originally. Without a manual and some sort of sight glass I am kind of guessing on this part, which I don't much like.
I plugged it in, and turned it on. It ran... for a while again, and tripped the breaker. Okay, I figured maybe that circuit had too many odds-n-ends plugged into it, so I went to another... ran for a while and tripped again. This time the thermal overload on the motor also tripped. The circuits it had been on before were 15A ckts. Tonight it tripped out even on 20A ckts. I thought maybe it was the voltage drop over the 25' extension cord... plugged it right into the receptacle (no extension cord) - tripped the breaker immediately. Tried another one - same thing.
So... at this point I'm kind of at a loss. *Something* is hosed, or not working as advertised, whether due to running low on oil over a period of time, or something else, and causing the motor to trip the breaker when it gets up to a certain pressure which probably corresponds to a given amount of work/friction/drag that it has to overcome. I'm not really in the mood to disassemble a compressor and go detective on it (although I may after finding out what it'd cost to have someone else do it!), so I'm open to suggestions. Who would you call at this point - Sears, a motor shop, some place else?