Bed heater

The bed heater is the resistive heating element embedded in the aluminum bed plate. It heats the print surface to improve adhesion and prevent warping during printing.

---

Assembly wiring (step 5.1 — Heated Bed Setup)

From the assembly manual (step 5.1), 1 operator, 5 min:

1. Connect the bed cable to the “BED” power box connector (step 5.1.1)
2. Connect cable [3] — the temperature sensor cable — to the bed (step 5.1.2)

The socket is labeled “BED” on the power box (under the panel box, right side of the machine). Always connect to the correct labeled socket.

Electrical connection

Danger

Critical: the bed heater cable must ALWAYS be plugged into the bed socket on the power box (firmware-controlled). Plugging it into the forced socket (always-on) causes uncontrolled heating and triggers the 110°C safety cutoff.

See Power outlets (power box) and Bed heater on wrong outlet for full details.

Parameter	Value
Power socket	bed socket on the power box (firmware-controlled, 220V)
Voltage	220–240V AC
Power draw	~2000 W
Control	Klipper firmware via SSR (solid state relay)
Safety cutoff	110°C — Klipper blocks/errors if the bed exceeds this

---

Temperature ranges by material

Material	Bed temp	Notes
PLA / rPLA	40–65°C	Lower is often better; 40°C sticks well, parts release on cooling. Too hot a bed makes PLA whiten and degrade — see note below
PETG	75–80°C	On bare glass, PETG can bond too strongly and chip the glass — use a release agent, see note below
PP	80°C	PP requires special bed surface — see Bed surface
Nylon	80–90°C	High warp risk; maximize brim

Caution

PLA whitens and lifts when the bed is too hot — it is PLA, not PETG, that does this. If the PLA bed temperature is too high, the material starts to degrade and detach from the plate. This is worst with several solid bottom layers (e.g. 3–4): the PLA does not have time to cool, begins to degrade, and lifts off the bed. Lower the bed temperature if you see PLA whitening or first layers curling up.

Caution

PETG on bare glass can flake the glass. Printed directly on glass, PETG can adhere so strongly that removing the part peels chips off the top surface of the glass. Use a release agent applied before every print:

• Dimafix — grips when hot, releases when cold (the intended behaviour)
• Rain-X wiped on with a cloth also protects the glass, but do not overapply — too much and the material will not stick at all and can climb up onto the nozzle and bond to the extruder insulation

See Bed adhesion sprays.

Warmup time and power consumption

Parameter	Value
Time to reach 80°C	~30 minutes
Peak bed power	~2000 W
Peak total (bed + printer)	~3 kW (~2 kW bed + ~1 kW printer)

Plan ventilation and circuit sizing accordingly. A dedicated 16A circuit is recommended for the printer + bed combination.

Caution

The bed sensor is in the centre of the plate. If you print large solid bottom layers directly over the centre (right above the sensor), the sensor can give a false low reading — the firmware then keeps heating, the real bed temperature overshoots past 110°C, and the safety cutoff trips into shutdown. If a print over the bed centre trips the 110°C error, suspect this rather than a sensor fault.

---

How it works

The bed heater is controlled by a solid state relay (SSR) inside the electronics box. Klipper applies PWM to the SSR to regulate power to the heater element. The NTC thermistor embedded in the bed plate provides closed-loop temperature feedback.

---

Failure modes

Bed not reaching temperature

• Check that the power cable is in the bed socket and the socket is live
• Most common cause: a loose SSR cable. When the bed does not heat, it is almost always because current is not reaching the bed — usually a loose connection on the SSR BED wiring, not a failed SSR or heater element. Double-check every connection on the SSR BED cable first.
• The heater element itself effectively never fails — do not assume a dead element. If no current arrives, look at the wiring/SSR connections
• If the bed graph shows no rise at all: confirm the SSR is switching (LED indicator should blink during heating); if it switches but no heat arrives, the fault is downstream in the cabling

Bed error at startup (110°C cutoff)

• Bed cable is plugged into the forced socket (always-on at full voltage) instead of the correct bed socket
• Or a large solid first layer printed over the centre sensor caused a false reading (see the centre-sensor note above)
• See Bed heater on wrong outlet

Print won’t start after heating or bed leveling

Note

Updated firmware behavior. The old upper-temperature block (print refused to start if the extruder was more than 20°C above target) has been removed. There is no longer a high-temperature hang.

The print now only waits if the extruder is more than 5°C below the slicer target — it heats up and then starts. If a print does not start, check the extruder has reached within 5°C of target.

Bed overheating / print sticks permanently

• For PETG: increase adhesion spray (Dimafix, Rain-X) and ensure the spray forms a release layer — without spray, PETG bonds so strongly it can crack the glass when the part is removed
• See Bed surface and Bed adhesion sprays

---

Bed leveling temperature note

Always run bed leveling with the extruder at printing temperature, not with the bed alone. A cold nozzle tip can trigger the probe arm prematurely. See Probe arm bending and Bed leveling system.

---

Related notes

• Bed heater on wrong outlet
• Power outlets (power box)
• Bed surface
• Bed leveling system
• Bed adhesion sprays
• Z offset and first layer