Replacing a WILDEN P4: What to Check Before You Order

A P4 is often bought to replace an older P4: the piping is already there and the same pump is wanted again. That is usually simple, as long as a few things are checked first.

• The full code on the nameplate, including any suffix. Several P4 builds end in /0014B, a factory option package, and they are not automatically interchangeable with builds that don’t
• The port layout. The P4 takes its inlet horizontally at the back and discharges vertically from the top. If your old pump discharges from the side, it may not be a P4
• The elastomer. PTFE, Buna-N and Neoprene are the most common of the 45 aluminum builds, and the choice should follow the fluid, not the last order
• Your air supply. Wilden’s example duty for the Buna-N build 04-0111 is 27 gpm (102 L/min) against 2.7 bar (40 psig), using about 22 Nm³/h (13 scfm) at 4.1 bar (60 psig)

For reference, the same build is rated at 76 gpm (288 L/min) maximum, 125 psi (8.6 bar) maximum air pressure and 19 ft (5.8 m) dry suction lift, for liquids from 32 to 175 °F (0 to 79 °C). It ships at about 38 lb (17 kg).

If the old P4 is past saving and you want better air efficiency, the XPS4 keeps the same vertical discharge. That makes it the easiest upgrade.

Example builds

The complete list of 45 aluminum P4 builds: https://www.haquanpump.com/wilden-aodd-pumps/part-numbers?q=P4