What does Bitzer error code E01 mean?

Error code E01 on Bitzer compressors indicates a high-pressure cutout. Check the discharge pressure against the maximum allowable pressure for your refrigerant, inspect the condenser for fouling or airflow restrictions, and verify the condenser fan motor is operating correctly.

How do I reset a Bitzer compressor after a fault?

After resolving the root cause, press and hold the reset button on the Bitzer control module for 3 seconds. For Bitzer CRII models with SABB, navigate to the fault log in the display and clear active faults. Always identify and fix the underlying fault before resetting to prevent repeated trips.

What causes a Bitzer screw compressor to trip on high discharge temperature?

High discharge temperature (E03) on Bitzer screw compressors is commonly caused by insufficient oil injection, a blocked oil separator, high compression ratio due to low suction pressure, or loss of economiser function. Check oil level and injection nozzles first, then verify suction pressure is within rated parameters.

How do I read the Bitzer LOGVIEW fault history?

Connect LOGVIEW software to the Bitzer CRII controller via RS485 or USB adapter. Navigate to the Fault History tab to see timestamped fault events with operating conditions at time of trip. This data is invaluable for diagnosing intermittent faults and trending compressor health.

What oil should I use in a Bitzer compressor with R404A?

Bitzer recommends BSE 55 or BSE 170 polyolester (POE) oil for R404A applications. Always use the viscosity grade specified on the compressor nameplate. POE oils are hygroscopic — keep containers sealed and replace oil if moisture contamination is suspected.

What is the correct superheat setting for a Bitzer reciprocating compressor?

Bitzer recommends 10-15K superheat at the compressor suction port for reciprocating models under normal operating conditions. Lower superheat risks liquid slugging; higher superheat increases discharge temperature and reduces efficiency. Use a digital manifold gauge set for accurate measurement.

What does the Bitzer SE-B1 / SE-B2 protection module do and how do I read its LED?

The Bitzer SE-B1 (single-phase) and SE-B2 (three-phase) modules are the standard protection modules on Bitzer semi-hermetic reciprocating compressors (Octagon, Ecoline). They monitor motor winding temperature via embedded PTC sensors, oil pressure differential via the Delta-pII oil pressure switch, and — on three-phase units — phase rotation and phase loss. A green LED on the module means the compressor is enabled to start; the LED extinguishes when the module trips, and the trip latches until the cause is cleared and supply is interrupted to reset. The newer SE-i and SE-C1 modules add an electronic display and digital interface but retain the same protection categories. PTC trips need 30 minutes to cool below the switch-back temperature before reset will clear.

How do I diagnose a Bitzer screw compressor IQ Module alarm?

The IQ Module fitted to Bitzer CSH / CSW / OS screw compressors is the integrated electronic protection and monitoring unit. Connect a laptop running BEST Software to the IQ Module's USB or RS485 port to read the active alarm and fault history with operating data at the time of trip. The IQ Module distinguishes between motor protection (PTC overtemperature, current limit, phase loss, direction), discharge protection (high discharge temperature, high discharge pressure), oil system (low oil pressure differential, low oil flow on the OFC oil flow switch, oil filter differential), and capacity/slide-valve faults. Lockouts that latch require BEST Software or the CM-RC-01 controller to clear; field-resettable warnings clear automatically once the operating condition recovers.

What causes a Bitzer compressor to trip on motor overload (E04)?

E04 / motor overload trips on Bitzer compressors come from the PTC winding sensors crossing the trip threshold (around 110-120°C depending on motor class). Root causes split into electrical and refrigeration. Electrical: supply voltage outside the ±10% nameplate window, single-phase condition on a three-phase unit, loose contactor terminations heating under load, or a failing motor winding losing insulation resistance. Refrigeration: liquid floodback on the suction side causing high motor current as the compressor tries to compress liquid, low refrigerant charge driving high discharge temperature back into the motor cavity (the suction-cooled motor relies on cool suction gas), or operating outside the published envelope. Megger the motor to ground (>1 MΩ), measure phase-to-phase winding resistance for balance, and verify suction superheat is within range before resetting.

What is the difference between Bitzer reciprocating, screw, and scroll compressor diagnostics?

Bitzer's three compressor families use different protection architectures. Semi-hermetic reciprocating (Octagon, Ecoline, Varispeed) uses the SE-B1 / SE-B2 / SE-i / SE-C1 module family with PTC motor sensors, the Delta-pII oil-differential pressure switch, and an external discharge thermostat — trip categories are motor temperature, oil pressure, discharge temperature, and (on three-phase) phase loss / direction. Screw compressors (CSH, CSW, OS series) use the IQ Module with the integrated BEST Software interface, adding oil-flow protection on the OFC switch and slide-valve position monitoring. Scroll compressors (Orbit family) use a simpler internal motor protector with an external discharge thermostat and no oil monitoring (oil-free or sealed-oil designs). Apply the correct diagnostic dictionary to the actual compressor architecture; SE-module categories do not map onto IQ Module categories one-for-one.

Quick Answer

Bitzer compressors diagnose through the SE-i, SE-B1, and SE-C1 protection modules on reciprocating units and the IQ Module on CSH / CSW / OS screw compressors. Faults latch into four categories: phase loss / direction, motor overload (PTC winding), oil temperature or oil flow loss, and discharge temperature or pressure relief — readable via LED, CM-RC-01, or LOGVIEW.

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By Nichita Herput

Co-founder & CEO · Reviewed May 2026

What error codes does Bitzer display?

E01

High pressure cutout — condenser fouling, fan failure, refrigerant overcharge, or non-condensables in the high side

E02

Low pressure cutout — loss of charge, restricted TXV, iced evaporator, or dirty filter-drier

E03

High discharge temperature — high compression ratio, low oil injection on screws, lost economiser, or undercharge

E04

Motor PTC overtemperature — supply voltage, phase loss, liquid floodback, or undercharge causing hot suction return

E05

Oil pressure differential fault (Delta-pII) on reciprocating units — low oil level, worn oil pump, or restricted oil filter

E06

Phase loss or wrong direction — SE-B2 / SE-i has detected missing or reversed phase rotation; swap any two phases at the contactor

E07

Oil flow fault on screw compressors — OFC oil flow switch has not made within the start window; check oil charge, filter, and solenoid

E08

Discharge temperature thermostat — external head-end thermostat has tripped on the discharge port; allow cooling and clear before reset

E09

Pressure relief / safety relief valve event recorded by IQ Module — inspect head and crankcase relief valves and pressures at trip

E10

Motor protection lockout — PTC sensor reading open or shorted, or repeated overtemperature trips have latched the SE / IQ Module

Common questions about Bitzer equipment

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