Peak Coffee

Safety-1st Custom-2nd  •  Ceramics ThermoFuse 185C  •  LEAD FREE PCB  •  Thermocouple K – M4 x “6mm”  •  Food Safe Component  •  Ship in 2 – 6 days  •  Safety-1st Custom-2nd  •  Ceramics ThermoFuse 185C  •  LEAD FREE PCB  •  Thermocouple K – M4 x “6mm”  •  Food Safe Component  •  Ship in 2 – 6 days  • 

Your machine

Showing Classic Pro / Eco / Evo · 100–120 VAC

Gaggiuino installation manual

Wiring your Gaggia, without the guesswork

Pick your machine above. Every diagram and table below follows it.

5earth points
6.3mm spade, mains
185°C ceramic fusePEAK exclusive
Kthermocouple, 6 mmcustom made

Read this first

  • Unplug it. Empty the boiler. Keep it unplugged for the whole build.
  • Earth every metal part. Buzz the chain out before you plug in.
  • Never run the boiler dry. Fill and prime before any heat test.
  • First power-on through an RCD/GFCI outlet.
  • If your machine doesn’t match a diagram, stop. Trust the machine, not the picture.

Mains voltage kills. If you are not confident, have an electrician do the high-voltage work. This mod voids the machine’s warranty.

Wiring schematic

The whole circuit, redrawn for the screen in your hand. A thermocouple reads the boiler, the board decides, the SSR switches the heat — the board never carries boiler current.

Ladder layout: live path on the left, neutral return on the right. Earth is its own chain — next section.

Wiring loom

Ships ready-made — 22 wires. Each row is one wire and both ends.

The two voltages use opposite colour codes. Here white is neutral, pump live is blue.Here blue is neutral, pump live is grey. Never mix looms — the wrong one still fits.

    Wire by part

    The same wires, grouped by the part in your hand. Work through one card, then move on.

    Earth chain

      Buzz out every link before you plug in. Probe from the plug’s earth pin to the warming plate, boiler body, 3-way valve and frame. All must beep. Get this wrong and the machine still makes coffee — which is what makes it dangerous.

      Switch panel

      Viewed from the back 1 2 3 4 5 6 7 8 Brew Steam On / Off
      Live in at 7, out at 7–8. Red terminals are the only ones carrying switched mains.
      Power — DPST P5 P4 L in → L out Brew — DPST signal → J7 Steam — DPDT signal → J7 lamp = boiler status
      Only the power switch carries mains. Brew and steam become signals. The steam lamp now shows boiler status — lit when not heating.

      Boiler & fuse

      Two elements, 2 mm pin receptacles — not spades. Earth stud takes a 6.3 mm spade. Thermocouple is Type K, ungrounded, M4 × 6 mm — custom made for these kits. Thermal paste, hand tight only.

      The ceramic thermal fuse is fitted, not optional. PEAK Coffee has this part made exclusively for these kits — a re-settable 185 °C, 16 A, M4 ceramic fuse that drops into the stock position. It is a second layer of protection on top of the coffee machine standard, and unlike the stock one-shot part you reset it by hand instead of stranding the machine.

      Never bypass the fuse. It is the last thing between a stuck SSR and a dry boiler glowing red.

      Connections

      TerminalGoes toType
      J10AC neutral — N-In6.3 mm spade
      J11AC line — L-In6.3 mm spade
      J12Pump — P-Out6.3 mm spade
      J133-way valve — 3-Out6.3 mm spade
      J4Thermocouple — Type K, ungrounded, 6 mmpolarised
      J6Pressure transducer, 0–1.2 MPa5V · GND · P
      J9SSR control — watch polarityGND · R1 · R2
      J7Brew + steam switchesJST-PH 2 mm
      J1Display — TX goes to RXGND · TX · RX · 5V
      J8ScalesD2 · 5V · GND · CLK · D1
      J5Extra IOGND · B15 · A12
      J27Programming / UARTheader

      Red-edged rows carry mains. Keep signal wires away from the mains bundle or temperature readings wander.

      Install order

      1. Unplug, drain, cool.
      2. Photograph the stock wiring from three angles.
      3. Strip the old harness — thermostats and their wiring come out.
      4. Fit the thermocouple with paste, hand tight.
      5. Mount the SSR on metal for heatsinking. Fork spades on all four terminals.
      6. Mount the board clear of the boiler and steam path.
      7. Build the earth chain first — then buzz it out.
      8. Neutral star from the socket to board, boiler, pump, valve.
      9. Live path socket → switch → SSR and board.
      10. Low voltage — thermocouple, transducer, switches, display.
      11. Tug-test every crimp. Re-check the earth chain.
      12. Fill and prime before any heat test.

      You’ll want: 6.3 mm crimp tool · fork spades · 2 mm pin receptacles · thermal paste · multimeter with continuity buzzer · nut drivers · Torx set.

      First power-on

      1. Before plugging in: continuity from plug earth to every metal part — all must beep.
      2. Before plugging in: no continuity L to N, or either to earth.
      3. Boiler full. Display comes up, temperature climbs smoothly to setpoint.
      4. Pump test with the portafilter out.
      5. Valve test — pressure should dump to the drip tray when brewing stops.

      Troubleshooting

      SymptomCheck first
      Nothing powers upThermal fuse; live path socket → L-In
      Board alive, screen blackRX/TX swapped at J1
      Temperature jumps aroundSignal wires next to mains; loose or grounded probe
      Boiler heats and never stopsSSR failed closed — unplug now
      Boiler never heatsSSR polarity at J9; thermal fuse
      Pump runs constantlyP-Out wired to a permanent live
      No pressure releaseValve live at 3-Out; valve earth
      Pressure reads zero5 V and signal at J6; G1/4 seal
      RCD/GFCI tripsStop. Live-to-earth fault. Do not retry

      Original diagrams

      The full-detail originals for your machine, for the bench rather than the phone. Tap to open at full size.

      Wiring loom laid out flat, every wire labelled with its destination
      Loom layout, as supplied.
      Full wiring schematic showing every component and terminal
      Full schematic — thick lines mains, thin lines low voltage.

      PEAK Coffee · Safety-1st, Custom-2nd