Description

The General Pump 47040409 is the standard 20mm ceramic plunger used in the “Workhorse” Series 47 pumps. Because these are triplex pumps, they are almost always sold or replaced in a set of three to ensure uniform pressure and stroke balance across the manifold.

Compatibility

This 20mm piston is the OEM replacement for the most popular belt-drive and gear-drive pumps in the industry:

• T Series 47: T1011, T1311, T1511, T2011, T9211.

• TS Series 47: TS1011, TS1311, TS1511, TS1711, TS2011, TS2021.

• Interpump Equivalent: WS101, WS131, WS151, WS201, WS202.

Why Replace Ceramic Pistons?

Ceramic is used for its extreme hardness and smooth surface, which minimizes friction against the seals. However, they are susceptible to:

1. Thermal Shock: The #1 cause of failure. If a pump runs in bypass (trigger closed) for too long and the water gets hot, hitting it with cold water can cause the ceramic to “shatter” or develop hairline fractures.

2. Scoring: If grit or sand enters the pump, it acts as an abrasive, grinding vertical “tracks” into the ceramic.

3. Cracked Bolts: If the internal piston bolt is over-tightened, it can put outward tension on the ceramic, causing it to crack from the inside out.