Description

The AR 2628 is a set of three precision 15mm ceramic plungers designed for the compact XT, XTA, and XTV Series pumps. These small-frame pumps are high-RPM units (usually 3400 RPM), meaning the pistons move very quickly and generate significant heat. Replacing these as a matched set is the only way to ensure the pump head remains balanced.

Compatibility

This kit is the OEM replacement for 15mm AR pumps, including:

• XTA Series: XTA3G16, XTA3G19, XTA3G22

• XTV Series: XTV3G16, XTV3G22

• XT Series: XT8.14, XT11.14

• Note: These are commonly found on electric and small gas pressure washers (under 6.5 HP).

Why Ceramic?

Ceramic is chosen for its ability to withstand friction without wearing down like metal. However, in these smaller pumps, they are vulnerable to:

1. Thermal Shock: If the pump runs in bypass (trigger closed) for more than 2–3 minutes, the water gets hot. When you pull the trigger, the sudden rush of cold water can “snap” the ceramic.

2. Overtightening: The piston nut on these small units requires very little torque. Crushing the ceramic is a common DIY mistake.

3. Winter Damage: Any water left behind the piston can freeze and expand, cracking the ceramic from the inside.

The “Fingernail Test”

Before installing your new AR 2628 set, check the old pistons:

• Dark Brown Staining: This indicates the pump was run dry or in bypass too long. The heat has cooked the seals onto the ceramic.

• Hairline Fractures: Look for tiny “veins” in the ceramic. These will allow high-pressure water to spray directly into your oil crankcase.

• The Ridge: If you can feel a vertical groove with your fingernail, the piston will act like a file and destroy your new water seals (Kit 2520) within minutes.