Centrifuges

Hettich ROTOFIX 32 A: troubleshooting and error codes

The ServiceForge knowledge base holds 20 documented symptoms for the Hettich ROTOFIX 32 A, with 41 ranked causes, 46 diagnostic checks with test points and expected values, and 27 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

No display

No power supply on control board, no display output, no operation possible

Ranked causes

1. No mains supply (common)
2. Fuses F1 or F2 defective (common)
3. Fuse F4 defective (type 1206-02 only) (occasional)
4. Power board (A1) defective (occasional)
5. Control panel (A3) defective (occasional)
6. Flat ribbon cable to control panel (A3) defective (occasional)
7. Overtemperature fuse F3 defective (occasional)

First check

Verify mains power supply to power board A1

Test point: S402L to S402N
Expected: Mains voltage present

3 more checks with pass and fail actions, 7 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Lid cannot be opened (display shows lid closed) patient safety

Lid lock will not release; rotation display indicates lid is closed and lid is physically closed

Ranked causes

1. Lid lock is defective (common)
2. Loose contact on plug S404 Pin 1 and 3 (occasional)
3. Power board (A1) defective (occasional)
4. Jumper for lid lock control incorrectly set on power board (A1) (occasional)

First check

Measure lid lock switch at plug S404

Test point: S404 Pin 1 and 3
Expected: As specified in section 11.3.4

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Lid cannot be opened (display shows lid opened) patient safety

Lid lock will not release; rotation display indicates lid is open but lid is physically closed

Ranked causes

1. Micro switch at lid lock is defective (common)
2. Loose contact on plug S404 Pin 5 and 6 (occasional)
3. Power board (A1) defective (occasional)
4. Jumper for lid lock control incorrectly set on power board (A1) (occasional)

First check

Measure micro switch at plug S404

Test point: S404 Pin 5 and 6
Expected: 0 Ω when switch closed; ∞ Ω when switch opened

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Lid lock Y1 malfunction

Lid lock cannot open or close properly; latch does not release or microswitch fails to detect lid position

Ranked causes

1. Relay REL 602 not energized or faulty (common)
2. Solenoid coil failure or mechanical latch jam (occasional)
3. Lid position microswitch failure (occasional)

First check

Verify mains power applied and rotor at standstill

Test point: Rotor, mains power indicator
Expected: Rotor stationary, mains power on

2 more checks with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Lid lock Y1 not engaging or supply voltage absent patient safety

Lid will not lock, voltage missing, or solenoid not responding

Ranked causes

1. Supply voltage absent at lid lock connector S404 (common)
2. Lid lock solenoid K1 coil open or defective (occasional)
3. Lid switch S404 pins 5-6 open or defective (occasional)

First check

Measure supply voltage at lid lock connector with rotor stopped

Test point: Plug S404, pin 1 to pin 3
Expected: Lid closed: 230 V (or 115 V); Lid opened: 0 V

3 more checks with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Brake resistor overheating high voltage

Overtemperature fuse F3 blows; power board separates from power supply during braking cycles

Ranked causes

1. Excessive braking cycles or prolonged braking (common)
2. Defective brake resistor R1 (occasional)

First check

Measure brake resistor R1 resistance

Test point: R1 on power board
Expected: Per equipment specifications
Tools: Ohmmeter

1 more check with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Brake resistor R1 fault or overtemperature fuse F3 blown high voltage

Brake resistor shows incorrect resistance or fuse shows high resistance

Ranked causes

1. Brake resistor R1 open or value out of tolerance (common)
2. Overtemperature fuse F3 open or defective (occasional)

First check

Measure brake resistor R1 resistance

Test point: Plug S405, pin 1 to pin 2
Expected: 230 V: 330 Ω; 120 V: 82 Ω

1 more check with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Centrifuge cannot start with lid closed patient safety

Centrifuge fails to start even when lid is properly closed; microswitch position not detected

Ranked causes

1. Lid microswitch not detecting closed position (common)
2. Power board not receiving lid position signal (occasional)

First check

Verify lid is fully closed

Test point: Lid position
Expected: Lid closed with no gap

2 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Centrifuge will not start

Power board refuses to start rotor when start command is issued; no rotation occurs

Ranked causes

1. Lid not closed or lid position microswitch failure (common)
2. Power board failure or control circuit fault (occasional)

First check

Verify lid is fully closed

Test point: Lid, lid lock latch position
Expected: Lid fully seated, latch engaged visibly

1 more check with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Motor not running or power loss at motor high voltage

Motor coil shows no resistance or incorrect overtemperature switch reading

Ranked causes

1. Motor coil open or disconnected (common)
2. Overtemperature switch triggered or defective (occasional)

First check

Measure motor coil resistance

Test point: Plug S401, between two motor lines
Expected: 230 V: 24.7 Ω; 120 V: 3.6 Ω

1 more check with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Imbalance switch-off

Verify imbalance detection triggers drive shutdown at correct weight differential before reaching 1500 RPM during run-up with loaded rotor

Ranked causes

1. Imbalance switch requires distance adjustment (common)

First check

Perform test run with loaded rotor having weight difference in opposite positions

Test point: Rotor 1624
Expected: 10 g to 15 g weight difference

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Functional check after repair patient safety

Complete test procedure validating unit operation including controls, timing, temperature, imbalance detection, current consumption, and electrical safety

Ranked causes

1. Repair completion requires validation testing (common)

First check

Verify function of keys, display, and LEDs

Test point: Control panel and display
Expected: All responsive and illuminated as designed

7 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Imbalance detected during operation

Imbalance switch S 2 activates, causing the drive to switch to braking mode during running operation (starting, centrifuging, or braking phases)

Ranked causes

1. Imbalance switch S 2 malfunction or incorrect activation (unknown)

First check

Verify imbalance switch S 2 operates only in running mode

Test point: Imbalance switch S 2
Expected: No activation at rest; activation only during start, centrifuging, or braking

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Imbalance switch S2 not functioning patient safety

Imbalance detection not working; switch fails to respond to rotor imbalance

Ranked causes

1. Imbalance switch S2 contacts stuck open or defective (common)

First check

Measure imbalance switch continuity at rest

Test point: Plug S503, pin 1 to pin 4
Expected: Switch closed: 0 Ω; Switch opened: infinite

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Intermediate voltage on power board A1 out of range high voltage

DC bus voltage incorrect during centrifuge run-up, run, or run-down

Ranked causes

1. Power supply rectification fault or capacitor bank degraded (rare)

First check

Measure intermediate DC voltage on power board A1 during run-up phase

Test point: Power board A1 intermediate bus
Expected: 230 V: 380 V DC; 120 V: 203 V DC

2 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Lid lock cannot be opened

Lid remains locked even when rotor has stopped and mains power is applied; latch does not release

Ranked causes

1. Relay REL 602 not energized (common)

First check

Verify rotor is at standstill

Test point: Rotor
Expected: Stationary

2 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Motor current out of specification high voltage

Current draw at motor terminals not as expected; possible winding short or control fault

Ranked causes

1. Motor winding short or insulation degradation (rare)

First check

Measure motor coil resistance after disconnecting S401

Test point: Plug S401 motor coil terminals
Expected: 230 V: 24.7 Ω; 120 V: 3.6 Ω

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

No speed indication / Machine-Version-Error

After switching on, speed indicator extinguishes and time indicator shows set machine version instead

Ranked causes

1. Wrong machine version adjusted (common)

First check

Verify machine version setting

Test point: Time indicator display
Expected: Machine version 7 for ROTOFIX 32 A

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

RCF key does not function

RCF key does not respond to pressing

Ranked causes

1. Wrong machine version adjusted (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Speed sensor (Tacho) B3 not operating

Tacho signal absent or voltage out of range at plug S502

Ranked causes

1. Power supply to sensor failed or disconnected (common)

First check

Measure power supply voltage at tacho sensor connector

Test point: Plug S502, pin 2 (GND) to pin 3
Expected: +8...+15V, +7 to +15 V

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Error codes

Code	Meaning	Trigger	Severity
`1`	Tacho error - speed sensor pulses stop during operation	Speed sensor signal loss detected during centrifugation	error
`-1-`	Tacho error	Tacho pulses break down during the run	error
`-2-`	System reset	Mains power interrupted during operation	info
`2`	System reset - power interruption during operation	Mains power interrupted during centrifugation run	error
`-3-`	Imbalance	Imbalance detected on motor axis during operation	warning
`3`	Imbalance - rotor imbalance detected on motor axle	Imbalance switch detects excessive rotor vibration	error
`-4-`	Communication	Communication error between control modules	error
`4`	Communication error between control and power boards	Communication failure between boards detected	error
`-5-`	Overload	Motor overloaded during operation	error
`5`	Overload - power board detects excessive current	Motor current exceeds maximum threshold	error
`6`	Overvoltage - intermediate circuit voltage excessive	Voltage in intermediate circuit exceeds limit during braking	error
`-6-`	Overvoltage	Mains voltage exceeds tolerance range	warning
`-7-`	Overspeed	Rotor speed exceeds maximum limit	critical
`7`	Overspeed - rotor speed 250 RPM above maximum	Speed sensor reading exceeds max rotor speed plus 250 RPM	error
`-8-`	Undervoltage	Mains voltage below tolerance range	warning
`8`	Undervoltage - mains voltage less than 20% of nominal	AC mains voltage drops below 20% of rated voltage	error
`9`	Overtemperature - motor temperature exceeds limit	Motor thermal switch opens indicating overtemperature	error
`-9-`	Overtemperature	Overtemperature switch in motor release activated	warning
`-c-`	Controller-Watchdog	Watchdog timer detects fault in power board	error
`-d-`	Lid lock error	Lid lock system fails to engage or disengage	warning
`d`	Lid lock error - lid open during centrifugation	Lid lock microswitch opens during centrifugation run	error
`-E-`	Short circuit	Short circuit detected in power board	critical
`E`	Short circuit - excessive current consumption detected	Power board detects short circuit condition	error
`-F-`	Rotor code	No speed sensor pulses detected during operation	error
`F`	Rotor code not detected after startup	No rotor identification code received within 15 seconds	error
`rot...`	New rotor identified and recognized by system	System detects different rotor installed than previously used	info
`Versions Error`	No speed indication on display	Display fails to show speed during operation	error

Likely causes and actions for each code are in ServiceForge. Connect ServiceForge to your AI

Community

0 fixes logged by technicians through their AI, with outcomes, for this model.

ServiceForge knowledge base record. Field-unverified unless technicians confirmed it. A teaching summary of the record, not a service manual. Export 2026-10-14.