Pre-Infusion Solenoid Troubleshooting - Steam LP

Pre-Infusion Solenoid Troubleshooting - Steam LP


Pre-Infusion Solenoid Troubleshooting - Steam LP


Slayer recommends that all service be performed by an experienced Slayer Espresso trained technician. 

Slayer Steam LP's Pre-Infusion solenoid is a 24v DC 3-way solenoid which enables a group to efficiently switch between between two brewing phases. Additionally, the Pre-Infusion inlet is the feed hydraulic path for maintaining a fully saturated brew tank.

Slayer Steam LP Pre-Infusion Assembly:



Group Cap Magnetic Reed Switches:
Refer to illustration below for magnet activation phases:
  1. Normally Closed:
    1. Pump OFF
    2. No water through group.
    3. Activates Autoflush feature if enabled.
  2. Normally Open:
    1. Manual Mode
      1. Idle: Pre-Infusion solenoid circuit is closed.
      2. Active: Pre-Infusion solenoid opens and allows through valve for Full-Brew extraction phase.
    2. Volumetric Mode
      1. Activates SHOT 2 Volumetric Recipe.


Actuator Positions:
Refer to illustration below for group activation phases:
  1. IDLE:
    1. Right, OFF (ghost actuator in POS 1 illustration).
  2. POS 1 (Pre-Infusion):
    1. Indexed actuator magnet moves away from N/C switch.
    2. Pump activates. (Does not contribute to water pressure during Pre-Infusion phase.)
    3. Water is moving through the Pre-Infusion brew circuit at 2.5bars of regulated line pressure.
  3. POS 2 (Full-Brew):
    1. Pump remains active.
    2. Indexed actuator magnet activates N/O switch.
    3. N/O switch sends signal to board to charge 24v DC Pre-Infusion solenoid.
    4. Solenoid opens and pump pressure water travels through valve.



Troubleshooting:

Tools:
#2 Philips Screw Driver
Multimeter

Parts:
99015-10035 Pre-Infusion Solenoid Assembly, Steam LP
30000-20042 MAG SWITCH, N/O, PINNED

Symptoms:
Hydraulic path stuck in either Pre-Infusion or Full-Brew, unresponsive POS 2 volumetric program, 'chattering' Pre-Infusion solenoid.

Solution Measure 1:
Verify N/O Magnet Switch is functional.

  1. Identify respective group switch. Labeled: SW-L.
  2. Set multimeter to continuity mode and place leads on male molex.
  3. Actuate group to Full-Brew. Circuit closes, continuity should be present.
  4. Adjust or replace N/O magnet switch.


Solution Measure 2:
Verify Pre-Infusion solenoid receives 24v DC when group is actuated to the far left, Full-Brew, position. 
  1. Raise display hood.
  2. Remove Pre-Infusion solenoid boot and reattach exposed terminal to valve.
  3. Set multimeter to DC and place leads on solenoid.
  4. Activate manual mode.
  5. Actuate and observe.


Video: Actuating through brew phases. Notice 24v DC is absent during POS 1 and OFF positions and present at Full-Brew position.




Questions or concerns? Please contact: support@slayerespresso.com

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