SUMMARY This article teaches you what to do when your chiller’s microprocessor returns a 999 error code. This error is often cause by a voltage spike that has corrupted the internal programming. SYMPTOMS Chiller microprocessor controller shows a “999” error code. In some cases the chillers compressor(s) may remain running below the desired set point. […]
Chiller Problem – Microprocessor Pressure Transducer Error
SUMMARY This article describes how to fix a chiller with a microprocessor that is not receiving proper input signal from the pressure transducer. SYMPTOMS Microprocessor shows an �Err� on the top screen and a pressure transducer error code on the bottom screen. Pressure transducer errors include: “tL1” for compressor 1 low-pressure sensor error. “tL2” for […]
Unlocking the Remote Micro
SYMPTOMS After installing the Legacy remote display micro-processor unit, user is NOT able to make changes to the system programming. CAUSE All Legacy remote display micro-processor units are shipped from the factory in the RDU – “STD MODE”. This will only allow review of the system program. In order to make changes to the chillers […]
Chiller System Problems – HTA & LTA alarms
SUMMARY This article describes what to do when there is an HTA alarm followed by an LTA alarm. SYMPTOMS HTA is indicated on micro display. After 5 seconds or so, the LTA comes on. I cannot change any set points through programming mode either. Also, I have just replaced both sensors thinking they were the […]
Chiller Problems – HTA alarm on chiller startup
SUMMARY This article describes what to do when your chiller’s HTA alarm sounds on initial startup. The problem is most likely due to a fluid temperature set above the set HTA temperature. SYMPTOMS Upon start up, (HTA) hi temp alarm received on micro CAUSE At the time initial startup, the microprocessor compares the process fluid […]
Chiller System Problems – Micro-processor won’t respond
SUMMARY This article teaches you what to do when your chiller system’s micro-processor won’t respond to programming mode. SYMPTOMS Pressing correct buttons to get into programming mode but the micro-processor won’t respond. CAUSE micro-processor is unable to confirm programming mode access request. RESOLUTION If holding the UP/DN buttons for 3-5 seconds does not change the […]
Variable condenser fan speed control
SYMPTOMS Chillers equipped with variable condenser fan speed control is tripping on high head pressure (Hi1) fault. Condenser fan(s) are not working properly. CAUSE ICM condenser variable fan speed control is not set properly or has been modified from factory settings. Control sensor(s) may not be secured to the proper location. RESOLUTION The attached PDF […]