What does GEA error code OL mean?

Error code OL on GEA equipment indicates compressor overload — check motor current draw. Refer to the GEA service manual for specific diagnostic steps and safety precautions before troubleshooting.

How do I reset a GEA unit after a fault?

To reset a GEA unit, first resolve the root cause of the alarm. Then power cycle the unit or press the reset button on the controller. For GEA systems with digital controllers, navigate to the fault log and clear active alarms. Never reset without investigating the cause.

Where can I find GEA service manuals and documentation?

Official GEA service manuals are available through authorised distributors and the GEA technical support portal. AskWhiz provides instant AI-powered access to GEA troubleshooting information via WhatsApp — no manual hunting required.

What is the difference between GEA Bock and GEA Grasso compressors?

GEA Bock (formerly Bock Kaltemaschinen) builds open-drive reciprocating and semi-hermetic compressors for transport, commercial, and small-industrial duty — typically HFC, HFO, CO2 or R290. GEA Grasso builds large industrial screw and reciprocating packages for ammonia (R717) and CO2 plants in food, dairy, beverage and pharma. Both ranges are now sold under GEA Refrigeration Technologies, but the controllers, oil systems and service procedures differ significantly between Bock open compressors and Grasso screw packages.

How do I read fault codes on a GEA Omni unit controller?

The GEA Omni 4 / Omni 4 LX unit controller (used on Grasso screw packages and current-generation industrial units) displays active alarms on its colour touchscreen under the Alarms / Events menu. Each alarm carries a numeric ID, severity (Warning, Trip, Lockout) and timestamp. The Trends and Event Log tabs show the last 100 events with timestamps for root-cause analysis. Connect a laptop via Ethernet to the Omni's web interface to download CSV alarm history for offline review.

What does a high discharge temperature alarm mean on a GEA Grasso screw compressor?

High discharge temperature on a GEA Grasso screw package (typically tripping above 95 °C on ammonia, 105 °C on R744) usually means insufficient liquid injection or oil cooling. Check the liquid-injection solenoid and TXV / EEV operation, oil cooler water flow and three-way mixing valve, oil level in the separator, and discharge pressure (high condensing pressure raises discharge temp). On ammonia plants verify the economizer / liquid-injection sequence is enabled in the Omni controller. Repeated trips degrade oil and damage rotor profiles.

What does an oil flow or oil differential pressure alarm mean on a GEA compressor?

Oil flow / oil differential pressure alarms (Omni IDs vary by package: typical names ‘Oil Pressure Low’, ‘Oil Filter dP High’, ‘Oil Flow Switch’) indicate the oil pump is not maintaining the required differential above suction pressure (typically 2.5–4.5 bar above suction on Grasso screws). Check oil level in the separator, oil filter differential pressure (replace at 0.8–1.0 bar dP), oil pump prelube circuit, oil temperature (cold oil is too viscous for screws), and oil-line solenoid valves. Never bypass an oil-pressure cutout — starvation destroys bearings within seconds.

What does a motor protection (Mp) alarm mean on a GEA Bock compressor?

GEA Bock semi-hermetic compressors use an INT69 / INT389 motor protection module that monitors PTC thermistors embedded in the motor windings. The Mp alarm trips when winding temperature exceeds approximately 120–40 °C — typical causes are repeated short-cycling, low evaporator load with insufficient suction-gas cooling, contactor chatter, or a phase loss. Allow the motor at least 30–60 minutes to cool, check supply voltage on all three phases, measure running current against the nameplate, and verify the suction superheat is not excessive before resetting.

How do I diagnose a refrigerant leak alarm on a GEA ammonia plant?

GEA ammonia (R717) plants use catalytic-bead, electrochemical or photoacoustic NH3 sensors mounted at machine-room ceiling level and at evaporator coils. The Omni controller logs each alarm with the sensor location and ppm reading. At 25 ppm a Warning typically posts; at 150–300 ppm an Evacuation alarm trips and the Emergency Pumpdown / Emergency Ventilation interlock fires automatically. Verify the alarm is real with a calibrated handheld detector, isolate the suspected circuit, ventilate per local IIAR / EN 378 procedures, and never silence an ammonia alarm without confirming the source.

What does HP cutout vs LP cutout mean on a GEA package?

HP (high-pressure) cutouts on GEA Grasso and Bock packages are mechanical or electronic safety switches set 1–2 bar below the relief valve setting (typical NH3 plant: HP trip 17–18 barg, relief at 19–20 barg). LP (low-pressure) cutouts protect against suction starvation and are set 0.5–1.0 bar above atmospheric to keep the plant out of vacuum. HP trips usually mean condenser fouling, fan failure, or non-condensables in the system; LP trips mean low refrigerant charge, plugged liquid line, closed solenoid, or excessive load loss. Both are typically manual-reset on the Omni after the fault is identified.

Quick Answer

GEA industrial refrigeration plants — Grasso screw packages and GEA Bock semi-hermetic compressors on ammonia (R717) or CO2 (R744) — run on Omni unit controllers. Common faults: high discharge temperature, oil flow / differential pressure trips, motor protection (Mp / INT69), HP / LP cutouts and ammonia leak alarms. Identify root cause before resetting any safety device.

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By Nichita Herput

Co-founder & CEO · Reviewed May 2026

What error codes does GEA display?

HDT

High discharge temperature on Grasso screw — check liquid injection, oil cooler flow and condensing pressure

Oil dP Low

Oil differential pressure below 2.5–4.5 bar above suction — check oil filter, pump prelube and oil level

Oil Filter dP

Oil filter differential pressure high — replace filter element at 0.8–1.0 bar dP

Motor protection (INT69 / INT389) PTC trip on Bock — cool 30–60 min, verify phases and FLA before reset

High-pressure cutout (typical NH3: 17–18 barg) — check condenser fouling, fan failure, non-condensables

Low-pressure cutout — check refrigerant charge, plugged liquid line and closed solenoid valves

NH3 Leak

Ammonia gas detection alarm — verify with handheld detector, ventilate per IIAR / EN 378 before reset

Disch Press High

Discharge pressure high warning — inspect condenser water flow, fan operation and purge non-condensables

Suction Superheat

Low or high suction superheat — check expansion valve, evaporator load and economiser sequence

Comm Loss

Omni controller communication loss to slide-valve actuator or VFD — check network cable, terminations and addresses

Common questions about GEA equipment

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