Applies To
  • Product: AAC/IK/A Series Chillers (e.g., AAC/IK/A 110)
  • Controller: Eliwell
Symptoms You may encounter the following issues during the commissioning or service of an AAC/IK/A series chiller:
  • The compressor is ramping up and down too quickly (short cycling).
  • The unit is generating an "ERROR 7" alarm, caused by the system running at low pressure due to rapid cycling.
  • The chilled water pump deactivates when the compressor cycles off, but the site requires the pump to run continuously whenever the system is in cool mode.
  • The temperature differential for compressor cut-in and cut-out is too narrow.
Cause
  1. Compressor Short Cycling: The primary cause is typically insufficient water volume in the primary hydraulic circuit (low system inertia). For the AAC/IK/A 110 model, the minimum required water content is 330 litres. A secondary cause can be the compressor hysteresis parameter (tr30) being set too narrow.
  2. Water Pump Operation: The parameter for continuous pump operation (P100) is not enabled by default.
Resolution
Access to the service parameters is required to make the following changes.
  • Service Password: 78
CAUTION: Only adjust the parameters specified below. Do not change any other settings without direct authorisation from the senior technical support team.

1. To Address Compressor Short Cycling

A. Verify System Water Volume (Primary Action) Before adjusting any parameters, the most critical step is to check that the primary hydraulic circuit meets the minimum water content specification.
  • Minimum Water Content (AAC/IK/A 110): 330 Litres
  • If the system's water volume is below this minimum, this must be rectified to ensure stable compressor operation.
B. Adjust Compressor Hysteresis (Secondary Action) If the system water volume has been confirmed as adequate, you can adjust the compressor hysteresis to widen the operational temperature band.
  1. Access the service menu using the password 78.
  2. Navigate to parameter tr30.
  3. The default value is 0.8°C. This can be lowered to a minimum of 0.5°C.
  4. Note: Lowering this value increases the temperature differential. Always consider the compressor's minimum off-time when making this adjustment.

2. To Enable Continuous Water Pump Operation

To set the water pump to run continuously whenever the unit is in cool mode (even when the compressor is off), follow these steps:
  1. Access the service menu using the password 78.
  2. Navigate to parameter P100.
  3. Change the value of P100 to 1. This sets the water pump to "always on" mode.***