General Maintenance

LUCCA M58: Cleaning Inlet Check Valve

Below are instructions for removing an inlet check valve on your Quick Mill LUCCA M58. This is useful if the check valve is allowing water back into the water tank or sending excess pressure out of the water line inlet. (Difficulty ☕☕☕)

Before testing this you can attempt to mix a citric acid solution in with your water in your water tank and draw about 4 ounces of the solution into your machine into the machine. If you run the group head for 14 seconds you'll have drawn about 4 ounces. Once this is done turn your machine off.

This will saturate the descale solution in the inlet assembly so that any scale on the check valve will be loosened and removed. After 45 minutes of waiting dump out the citric acid solution from your water tank and refill it with regular water. Draw 8 ounces of water out of the group head to get all of the citric acid out of the inlet assembly and then follow these instructions to drain the boilers and refill them with fresh water. If your machine is still leaking follow the instructions below.

Tools required:

  • 2x adjustable wrench
  • 12mm crescent wrench
  • 15mm crescent wrench
  • 17mm crescent wrench
  • Diagonal cutters (or scissors)

First, remove the panels.

V2 Lucca M58:
1. Remove the water reservoir tray to access the check valve and OPV assembly. Identify the check valve.

2. Remove the steam boiler line compression fitting.


3. Remove the brew boiler fitting connection.


4. Remove the flexible tube from the top of the OPV.

5. Use two wrenches to unscrew the check valve.


6. Remove the internal check valve components and soak in a descaling solution to clean.


7. Reassemble the check valve and reinstall in the machine. It may be helpful to reconnect the fittings in the same order they were removed, i.e. steam boiler fitting first, brew boiler fitting next, then flexible tube.


V1 Lucca M58:

LUCCA M58: Cleaning Inlet Check Valve
LUCCA M58: Cleaning Inlet Check Valve
LUCCA M58: Cleaning Inlet Check Valve
LUCCA M58: Cleaning Inlet Check Valve

Rebuild and test.