What error codes does a Climaveneta chiller display?

Climaveneta water-cooled and air-cooled chillers, heat pumps, and AHUs use the W3000 / W3000+ controller (with ECPM on multi-circuit modular platforms and NCS for plant-level supervision) and surface faults using a category-prefix taxonomy. The most common categories are HP (high-pressure switch trip on the affected refrigerant circuit), LP (low-pressure switch trip), AT (antifreeze hard lockout when leaving chilled-water temperature drops below the antifreeze setpoint — stops the compressor immediately), AS (antifreeze soft alarm or sensor fault), Cp (compressor thermal / motor protection / inverter trip), OL (oil-pressure fault on screw-compressor platforms), FL (flow-switch fault on the evaporator or condenser water circuit), and Pr (probe / sensor open or shorted). The W3000 alarm log records the originating circuit and compressor index for multi-circuit units, so a typical entry reads HP1, LP2, AT, FL-evap, etc.

What does an HP alarm mean on a Climaveneta chiller?

HP (High Pressure) is a hard lockout that fires when the high-pressure switch on the affected refrigerant circuit opens. On air-cooled units, the dominant causes are condenser-coil fouling (clean the coil with low-pressure water and an alkaline coil cleaner), failed condenser-fan motor or fan-speed controller (verify all fans rotate in the correct direction at full RPM), refrigerant overcharge, or non-condensable gas trapped in the circuit (recover, evacuate to 500 microns, recharge by weight). On water-cooled units, also check condenser-water pump operation, condenser flow rate against the manual setpoint, condenser inlet water temperature against the operating envelope, and the cleanliness of the brazed-plate or shell-and-tube condenser. On the W3000, manual reset is required after the underlying cause is corrected — the controller will not auto-clear an HP lockout.

What does an LP alarm mean on a Climaveneta chiller?

LP (Low Pressure) is a hard lockout that fires when the low-pressure switch on the affected circuit drops below its setpoint. The most common root cause is refrigerant undercharge from a slow leak — perform a leak search on flare connections, brazed joints, the brazed-plate evaporator, and Schrader cores; recover the remaining charge, repair the leak, evacuate to 500 microns, and recharge by weight. Also check evaporator water flow (low chilled-water flow starves the evaporator of heat and pulls suction pressure down), evaporator fouling, expansion valve travel and superheat setting, suction filter cleanliness, and operation outside the unit's minimum chilled-water leaving temperature envelope. On heat-pump units in heating mode, an LP trip on the outdoor coil during defrost recovery is normal and self-clears; persistent LP outside defrost windows indicates a real fault.

What is an AT antifreeze trip on a Climaveneta chiller and how do I clear it?

AT (Antifreeze Trip) is a hard lockout that fires when the chilled-water leaving temperature drops below the antifreeze setpoint configured at commissioning — typically 3 °C (37 °F) on plain water and lower on glycol systems with the setpoint adjusted per the freeze point of the actual fluid mix. The W3000 stops the compressor immediately to prevent evaporator freeze damage. Manual reset is required. Before resetting, identify the cause: low evaporator water flow (verify pump operation, balancing valve position, and filter cleanliness), an aggressive setpoint override from BMS / NCS, expansion valve hunting on partial-load conditions, sensor drift on the evaporator outlet probe (compare to a calibrated reference thermometer), or a glycol concentration that is lower than the antifreeze setpoint assumes. If you reset AT without correcting the cause, the next trip can damage the evaporator brazed plates — a much more expensive repair than diagnosis time.

What are AS soft alarms on Climaveneta chillers?

AS (Antifreeze Soft alarm / sensor) is the second-tier antifreeze warning. The W3000 surfaces AS when the evaporator leaving temperature is approaching but has not yet crossed the AT hard-lockout setpoint, when the antifreeze sensor itself reads out of expected range, or when a probe disagreement between two redundant antifreeze sensors exceeds tolerance. AS does not stop the compressor on its own — it warns the technician that AT is imminent if conditions continue to drift. Common causes: glycol concentration drifted lower than commissioned (refractometer-test the loop fluid), reduced evaporator flow that has not yet reached the full freeze envelope, or a degraded antifreeze sensor (typical Pt1000 RTD wired into the W3000 — measure resistance against a temperature reference). Treat AS as a service trigger before AT trips and locks the unit out.

What does a flow-switch (FL) alarm mean on a Climaveneta chiller?

FL (Flow) alarms protect Climaveneta chillers against running with insufficient evaporator or condenser water flow. The W3000 monitors a paddle or differential-pressure switch on each water circuit and locks the affected compressor circuit out within seconds of a low-flow detection during compressor operation — running a chiller dry causes evaporator freeze (DX models) or condenser overheating (water-cooled). Diagnostic sequence: verify the chilled-water and condenser-water pumps are running with correct rotation (three-phase pumps installed by an electrician without phase verification can spin backwards and produce zero flow), check pump strainers and basket filters for debris, confirm balancing-valve and isolation-valve positions, measure differential pressure across the evaporator and compare to the design dP curve in the IOM, and inspect the flow switch itself for sticking paddles, fouled differential-pressure ports, or wiring breaks at the W3000 terminal.

What does a Pr probe / sensor fault mean on the Climaveneta W3000?

Pr (Probe) faults are logged when a temperature or pressure transducer reads open, shorted, or out of expected range. The Climaveneta W3000 monitors several sensors per circuit: evaporator inlet and outlet water temperature (Pt1000 RTD), condenser inlet and outlet (Pt1000 RTD), ambient air temperature on air-cooled units (Pt1000), suction pressure transducer (4–20 mA, ratiometric), and discharge pressure transducer (4–20 mA). The alarm message identifies which probe is faulted (e.g., Pr-Tcond-out, Pr-Pdis-c1). Diagnosis: power down, disconnect the sensor from the W3000 input terminal, and measure resistance (Pt1000) or current loop (4–20 mA pressure transducer) against a calibrated reference. Inspect the cable for pinched insulation, water ingress at the gland, or chafing against sheet metal. Sensor wiring on Climaveneta units is typically twisted-pair shielded; ground the shield only at the W3000 end to avoid ground loops.

What does an ECPM module fault mean on a modular Climaveneta chiller?

ECPM (Electronic Control for Power Modules) is the per-module slave controller on Climaveneta multi-circuit and modular platforms (Integra and similar lines). Each ECPM supervises one compressor circuit and reports to the W3000 master via an internal CAN / RS485 bus. ECPM faults forwarded to the W3000 include inverter trip on variable-speed scroll or screw modules (check inverter overcurrent, IGBT temperature, and DC-bus voltage in the inverter event log), motor protection trip on the affected compressor (winding-thermistor circuit open or compressor running outside the operating envelope), and module communication loss between an ECPM slave and the W3000 master (check the bus cable for damage, terminating resistors at both ends, and 24 V auxiliary power to the ECPM module). The W3000 will continue to operate the remaining healthy modules in degraded capacity while a single ECPM is faulted, but plant-level setpoints may not be met under high load.

How does the NCS controller affect Climaveneta plant-level alarms?

NCS (Network Control System) is Climaveneta's plant-level multi-unit sequencer and BMS gateway. NCS aggregates alarms from multiple W3000-equipped chillers in a plant, sequences them based on demand and runtime, and exposes a Modbus RTU / Modbus TCP / BACnet MS-TP / BACnet IP register map to the building management system. NCS-originated faults visible on the W3000 include BMS communication loss (check the upstream Modbus / BACnet wiring, baud rate, and address conflicts), sequencing logic faults (e.g., a chiller commanded to start but failing to confirm running within the expected window), remote setpoint override conflicts (BMS commands a setpoint outside the configured min/max envelope), and time-synchronization faults if NCS depends on an NTP server for runtime accounting. Field service typically isolates the issue by disabling BMS supervision temporarily and confirming each unit operates correctly in standalone mode, then re-enables BMS and bisects the integration layer.

When should I call Climaveneta service rather than self-troubleshoot?

Call Climaveneta / MEHITS service (or an authorised distributor) when: the W3000 reports repeated AT antifreeze trips after you have verified flow, glycol concentration, and sensor calibration (evaporator damage may already be present); the W3000 logs internal RAM / EEPROM faults or boots in restricted mode (controller-level failure requiring firmware reload or board replacement); inverter modules on variable-speed compressors throw repeated DC-bus or IGBT faults (warranty-covered repair on high-voltage power electronics is technician-restricted); refrigerant leaks affect more than one circuit on the same unit (potential brazed-plate evaporator failure); or ECPM communication loss persists after replacing the bus cable and confirming termination. For routine HP / LP / FL / Pr alarms with clear root causes, AskWhiz can walk a competent commercial-HVAC technician through the W3000 diagnostic sequence and IOM-cross-referenced fix steps via WhatsApp.

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Climaveneta error codes, decoded.

Look up any Climaveneta fault code below. Each one is grounded in Climaveneta's own service documentation — the meaning, the symptoms, the causes, and the steps to clear it.

Quick answer

Climaveneta is the Italian commercial-HVAC brand (chillers, heat pumps, air-handling units) inside Mitsubishi Electric Hydronics & IT Cooling Systems (MEHITS). Alarms surface on the W3000 / W3000+ unit controller (ECPM on multi-circuit modules, NCS at plant level) using a category-prefixed taxonomy: HP (high-pressure trip), LP (low-pressure trip), AT (antifreeze hard lockout), AS (antifreeze soft alarm), plus compressor, oil, flow, and probe faults per refrigerant circuit.

By Octavian Ghindea

Co-founder & CTO · Reviewed May 2026

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What error codes does Climaveneta display?

Tap a code for the full breakdown — meaning, symptoms, causes, and fix steps.

High-pressure switch trip on affected circuit — inspect condenser fouling, fan operation, refrigerant charge, and non-condensables

Low-pressure switch trip — leak-test for refrigerant undercharge, verify evaporator flow, check expansion valve and suction filter

Antifreeze hard lockout — leaving chilled-water temperature dropped below antifreeze setpoint; manual reset required

Antifreeze soft alarm / sensor warning — approaching AT setpoint or antifreeze probe out of range

Flow-switch fault on evaporator or condenser water circuit — check pump rotation, strainer, and dP across heat exchanger

Compressor protection trip — motor winding overheat, phase-loss / phase-reversal, or inverter fault on VFD platforms

Oil-pressure fault on screw-compressor platforms — verify oil charge, oil filter, and oil-pressure transducer

Probe / sensor fault — W3000 input reading open, shorted, or out of range; identify faulted sensor in alarm log

ECPM-COMM

Communication loss between ECPM module and W3000 master — check internal CAN / RS485 bus cable, termination, and 24 V supply

BMS-COMM

NCS / BMS communication loss — verify Modbus / BACnet wiring, baud rate, address, and upstream supervisor health

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