iCHILL is a controller, not a make of chiller. The CX versions covered here are fitted by several manufacturers, including the MTA iC range (IC121CX or IC208CX) and CF Chillers, among others.
If your display is marked IC100CX, IC121CX, IC200CX or IC208CX, these are your codes, whatever name is on the cabinet. Note that the MTA TAEevo range uses the IC121C, which runs a different alarm set: see our TAEevo A-code guide.
Quick answer
On a Dixell iCHILL controller, alarm codes starting with A relate to the unit as a whole (flow, pumps, configuration), codes starting with b relate to a refrigeration circuit (pressures, antifreeze, fans), and codes starting with C relate to an individual compressor. The number in a b or C code is the circuit or compressor number, so b1HP is a high-pressure trip on circuit 1 and C2tr is a compressor 2 overload.
Press the menu key to open the function menu, scroll to the ALrM item and press SET. The bottom display shows the alarm code and the top display shows either rSt, meaning the alarm can be reset from here, or NO, meaning it cannot be reset until the underlying condition clears. Use the up and down keys to scroll through multiple alarms.
The controller also keeps an alarm log (ALOG), which stores up to 100 events. That log is often more useful than the live alarm, because it shows whether a fault has been tripping repeatedly for weeks.
Compressor overload alarms that have gone to manual reset are reset separately, through the COtr menu item, and may ask for a password.
| Code | Meaning | What usually causes it | Who can deal with it |
|---|---|---|---|
| AEFL | Evaporator flow alarm | The most common alarm we attend. Blocked strainer, failing or airlocked pump, closed valve, flow switch fault, or glycol that has thickened in cold weather. Compressors stop. | Site team can check |
| ACFL | Condenser flow alarm | Same causes on the condenser side of a water-cooled unit: pump, strainer, valve or flow switch. | Site team can check |
| AtE1 / AtE2 | Evaporator pump overload (main / support pump) | Pump motor overload has tripped. Seized or stiff pump, electrical fault, or an overload set too tight. | Site team can check, engineer if it repeats |
| AtC1 / AtC2 | Condenser pump overload (main / support pump) | As above, on the condenser circuit. | Site team can check, engineer if it repeats |
| AEht | High water temperature at evaporator inlet | Return water hotter than the unit expects: process load above design, a hot fill after a shutdown, or insufficient cooling capacity. | Site team can check, engineer if it persists |
| AELt | Low evaporator inlet temperature (heat pump mode) | Return fluid colder than the setpoint band allows. | Engineer needed |
| Aedt | Inlet to outlet temperature differential alarm | Flow too low for the load, or a probe reading incorrectly. Often flow related rather than refrigeration related. | Site team can check flow, engineer for probes |
| AEUn | Unloading due to high evaporator water temperature | The controller is protecting itself by shedding capacity, not a failure as such, but it points to an undersized or overloaded system. | Engineer needed |
| AtSF | Supply fan overload (air handling units) | Fan motor overload tripped. | Engineer needed |
| AEP1 / AEP2 / ACP1 / ACP2 | Pump maintenance warnings | Running hours have passed the maintenance threshold. A service reminder, not a fault. | Site team can clear, raise at next service |
| ALc1 / ALc2 | Generic alarms 1 and 2 | Whatever the machine builder wired to the generic alarm input. Could be a phase monitor, a leak detector or an external interlock. Check the wiring diagram. | Engineer needed |
| AFr | Supply frequency alarm | Mains frequency outside limits, or a supply problem. Often seen after a power event. | Site team can check supply, then engineer |
| ACF1 to AC11 | Configuration alarms | The controller’s configuration does not match the hardware. Usually follows a controller replacement or a parameter change. Not a mechanical fault. | Engineer needed |
| AEE | EEPROM alarm | Controller memory fault. Usually means a replacement controller or reprogramming. | Engineer needed |
| Atr1 / Atr2 | Remote terminal configured but not connected | Remote keypad missing, unplugged or a cable fault. The display may also show noL (no link). | Site team can check connections |
| ArtC / ArtF | Clock alarm and clock failure | Real time clock needs setting, often after a long power outage. Affects time-based functions such as energy saving. | Site team can reset the clock |
In these codes the number is the circuit: b1HP is circuit 1, b2HP is circuit 2.
| Code | Meaning | What usually causes it | Who can deal with it |
|---|---|---|---|
| b1HP / b2HP | High-pressure switch tripped | Dirty or blocked condenser coil, failed condenser fan, high ambient temperature, restricted airflow, or overcharge. On water-cooled units, loss of condenser water. Do not keep resetting it. | Site team can check the coil and fans, engineer for the rest |
| b1LP / b2LP | Low-pressure switch tripped | Usually refrigerant loss through a leak. Also expansion valve or solenoid faults, a blocked filter drier, icing, or low flow through the evaporator. | F-Gas engineer needed |
| b1hP / b2hP | High condensing pressure or temperature from the sensor | Same causes as the high-pressure switch, but detected by the transducer or probe before the safety switch trips. | Site team can check the coil and fans, engineer for the rest |
| b1lP / b2lP | Low condensing pressure or temperature | Often cold ambient with fan control not holding head pressure, particularly in winter. | Engineer needed |
| b1AC / b2AC | Antifreeze alarm in chiller mode | Evaporator fluid approaching freezing. Low flow, weak or absent glycol, incorrect setpoint, or a faulty probe. See our glycol concentration guide. | Site team can check flow and glycol, engineer if unclear |
| b1AH / b2AH | Antifreeze alarm in heat pump mode | As above, with the unit running in heat pump mode. | Site team can check flow and glycol, engineer if unclear |
| b1tF / b2tF | Condenser fan overload | Fan motor overload tripped: seized bearing, damaged blade, electrical fault or debris in the guard. | Engineer needed |
| b1PH / b1PL | Pump-down alarms at stop and start | The circuit has not pumped down within the allowed time. Solenoid valve, pressure switch or refrigerant charge issues. | F-Gas engineer needed |
| b1dF / b2dF | Bad defrost | Defrost did not complete in time. Heat pump applications only. | Engineer needed |
| b1Cu / b2Cu | Unloading from condenser or evaporator conditions | The controller is shedding capacity to protect the circuit, usually because of high condensing or low evaporating conditions. | Engineer needed |
| b1ds / b2ds | Circuit disabled from the keyboard | Someone has disabled the circuit in the menu. Common after maintenance, and easy to miss when a unit seems down on capacity. | Site team can re-enable |
Not sure whether it is safe to reset? Send us a photo of the display and we will tell you what it needs before anyone travels. Call 0121 820 8946.
Here the number is the compressor: C1tr is compressor 1.
| Code | Meaning | What usually causes it | Who can deal with it |
|---|---|---|---|
| C1tr / C2tr | Compressor overload | Overload or internal protector has tripped: electrical fault, high load, low voltage or a failing compressor. After repeated events the controller forces manual reset through the COtr menu. | Engineer needed |
| C1HP / C2HP | Compressor high-pressure switch | A high-pressure switch fitted to that compressor rather than the circuit. Same causes as b1HP. | Engineer needed |
| C1oP / C2oP | Oil pressure or oil level switch | Oil starvation. Poor oil return, refrigerant migration, low charge or a failing oil pump. Treat as serious: this is how compressors are lost. | F-Gas engineer needed, stop the machine |
| C1dt / C2dt | High discharge temperature | Low charge, high compression ratio, failing valve or expansion problems. Another one not to keep resetting. | F-Gas engineer needed |
| C1Mn / C2Mn | Compressor maintenance warning | Running hours threshold reached. A reminder rather than a fault. | Site team can clear, raise at next service |
| C1dS / C2dS | Compressor disabled from the keyboard | Disabled in the menu, often left over from a previous visit. | Site team can re-enable |
Codes and behaviour vary with the machine builder’s parameter settings, so treat this as a guide rather than a substitute for the manual for your specific unit.
Send us a photo of the display and the data plate and we will tell you what it means and what it needs. Our engineers cover the West and East Midlands with a 4-hour response target, and support sites further afield by arrangement.
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