U.S. Seal PS200 Mechanical Seal Assembly

The U.S. Seal PS200 is the mechanical shaft seal assembly used on a large share of residential pool and spa pumps. It seals the motor shaft where it passes through the seal plate into the wet end, keeping pool water out of the motor. When a pump starts dripping between the housing and the motor, this is almost always the part that has worn.

One seal, several numbers

The same seal is catalogued as PS-200, PS-3867, 35-423-1020 and 5250-210 by different pump makers and distributors. If your parts list shows any of those, this is the replacement. It is listed for the Pentair Challenger high head and high flow models and for the Aqua-Flo Dominator high head and Tub-Master TMCP series pumps.

Fitting it

The assembly includes both halves of the seal. Clean the seal plate bore and the shaft, press the stationary half into the plate and slide the rotating half onto the shaft without touching the polished faces. A light film of silicone lubricant on the rubber parts helps them seat. If the pump has been leaking for a while, check the motor bearings while it is apart.