Pulling the portafilter after a shot and finding a soupy, wet puck? On machines with a three-way solenoid valve, that valve releases pressure after brewing. When it sticks, pucks stay wet and pressure lingers.
Here is how the solenoid valve works and how to fix it.
This article will teach you:
- What the solenoid valve does
- Why it sticks
- What to try first
- When it has failed
Why the Solenoid Valve Fails
- Scale binding the valve.
- Coffee residue in the valve path.
- A worn valve seal.
- An electrical fault in the coil.
What You’ll Need
- Descaling solution
- A backflush blind basket and cleaner
- Your owner’s manual
How to Fix a Sticking Solenoid Valve
- Backflush. Use a blind basket and espresso cleaner to flush the valve path.
- Descale. Run a descale cycle to free scale in the valve.
- Cycle it. Run several brew and stop cycles to work the valve.
- Test the release. Confirm pressure releases and the puck comes out drier.
Pro Tip: A wet, sloppy puck is the classic sign of a three-way valve that is not releasing pressure. Regular backflushing keeps the valve clean and is the best prevention.
When to Look a Little Deeper
Because the valve sits in the water path, it helps to check flow, and reviewing a machine that will not pump, a steam leak, or a water tank leak can reveal related issues.
When to Call a Pro
If backflushing and descaling do not free the valve, the solenoid coil or valve body may need replacing. That repair is best left to a technician.
Wrapping Up
A sticking valve leaves wet pucks. Here’s the recap:
- Backflush with a blind basket.
- Descale the machine.
- Cycle the valve to free it.
- Replace the valve if it stays stuck.
Backflush first, and drier pucks usually return. You’ve got this.