Issue:
Low Evaporator Temperature...Unit Off diagnostic
Resolution:
CH530 Controls:
Any of the evap sat temps fell below the water temp cutout setting while the respective evap liquid level was greater than 21.2mm (-0.83 inch) for 30 degree F seconds while Chiller is in the Stop mode, or in Auto mode with no compressors running.
- Energize Evap Water pump Relay until diagnostic auto resets, then return to normal evap pump control.
- Automatic reset occurs when either the evap temp rises 2F (1.1C) above the water temp cutout setting or the liquid level falls below 21.2mm (-0.83 inch) for 30 minutes.
LWTC - Leaving Water Temperature Cutout
- The LWTC (or Chilled Water Temperature Cutout) should be set to 5F below the lowest allowable Chilled Water Set Point based on the % Glycol.
- If the system has glycol, an adjustment of the Low Leaving Water and Low Evaporator Temperature Cutouts temperature cutouts may be necessary
- Validate that the chiller is controlling the pump for proper protection of the chiller
- Validate the accuracy of the pressure transducers
- Validate operation of Liquid Level Sensor
- Validate operation of the EXV
Notes:
Changes:
Other Question/Problem/Cause Statements:
- Low Evaporator Temperature...Unit Off?
- Low Evaporator Temperature Circuit 1: Unit OFF?
- Low Evaporator Temperature Circuit 2: Unit OFF?
- Low Evaporator Temp - Ckt 1: Unit OFF?
- Low Evaporator Temp - Ckt 2: Unit OFF?
- Low Evap Temp Unit Off?
- Low Evaporator Temp Unit Off?
- Low Evaporator Temperature Unit Off?
Facts:
- Air-Cooled Chiller (Pueblo) (RTAC)
- Water-Cooled Chiller (Pueblo) (RTHD)
- Chiller has glycol
- Cold ambient temperatures
Document Identifier: DOC-86091, DOC-86276
Document Identifier: 86091, 86276
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.