Adjusting the Pump Pressure on the La Marzocco Linea PB

Adjust Pump Pressure - Linea PB


The Linea PB utilizes a single external pump for managing espresso brewing pressure and autofill functionality for the espresso machine. Set at install and checked during Preventative Maintenance, this guide demonstrates the process for adjusting the pump.



Tools:
  1. Stubby Flathead Screwdriver
  2. Small Adjustable Wrench

Step 1: Locate Pump Assembly
Idea
Tech Tip! Machine must have water and power turned ON prior to adjustment!
  1. Pump assembly is wall mounted underneath the espresso machine.
  2. An adjustable bypass screw allows for precise flow control through the pump.
    1. Red arrow points towards pump head and bypass screw!

Example under counter pump location. Illustrations not to scale.

Step 2: Adjust Pump
The Linea PB utilizes a single gauge to monitor steam and brew pressure.
  1. Pressure Gauge - Linea PB

To accurately adjust the pump, the machine must be ON and the pressure gauge visible.
  1. Activate any brew button...
  2. Pump will activate and brew pressure dial should read ~9 bars.
  3. If dial does not read 9 bars:
    1. Loosen the black plastic lock nut with a small adjustable wrench.
    2. Adjust bypass screw using a stubby flat head screw driver:

  1. CLOCKWISE - increases pump pressure.
    1. Righty tighty!
  2. COUNTER-CLOCKWISE - decreases pump pressure.
    1. Lefty loosey!
Idea
Tech Tip! Adjust pump at bypass screw in quarter/half turn increments. Deactivating the brew button periodically will allow for back pressure to be relieved from the brew circuit. Repeat until 9 bars is achieved.

Step 3: Post Service Checklist
  1. Pull an espresso shot and observe gauge.
  2. If gauge remains at 9 bars, tighten plastic lock nut to secure bypass screw.
  3. Be careful not to over tighten plastic lock nut!
    1. Snug is enough.