Sta-Rite Impeller, 1/2 HP Full Rate and 3/4 HP Up Rate, C105-92PS

The Sta-Rite C105-92PS is the pump impeller for 1/2 horsepower full rate and 3/4 horsepower up rate pumps.

Full rate and up rate

The two ratings on this part are not a mistake. Manufacturers build a single pump body in full rate and up rate versions, and the impeller is what tells them apart. An up rate pump wears a higher horsepower number for roughly the same work, so when you order an impeller you have to match the rating on the pump rather than just the horsepower on the label.

What a tired impeller looks like

Impellers wear from the inside out. Sand and grit passing through the vanes gradually widen the clearances until the pump spins at full speed while moving noticeably less water. The symptoms are weak returns, low filter pressure and a suction cleaner that has gone sluggish, with a motor that still sounds perfectly healthy. Debris packed into the vanes produces the same result but arrives suddenly, so always look through the vanes before deciding the part is worn out.

Doing the job

Getting the impeller off means separating the seal plate and pulling it from the motor shaft, which exposes the shaft seal. A seal that has been disturbed seldom reseats reliably, so order one alongside the impeller and change both together rather than chasing a drip a week later.