Issue:
Chilled water flow (Ent Wtr Temp): The entering evaporator water temperature fell below the leaving water temperature by more than 2 degrees F.
Resolution:
RTAA, RTWA, RTUA, CGWD, CCAD, CGWE, CCAE, CGAD, CGAE
- Check the Test Points on the 1U1 module (RTAA, RTWA, RTUA only)
- Check Water flow
- Water Flow Direction
- Water temperature sensors reading correctly
-
Sensor depth
- Check the sensor depth. It should be a minimum of 2.25 inches from the end of the sensor where the wires come out of the sensor to the bottom of the adapter that threads into the coupling that is welded on to the evaporator
- The evaporator may be fouled or has debris inside it
- Sensor Crooked
- Minimum Loop Time 2 minutes met (proper volume of water in system)
Notes:
Changes:
Other Question/Problem/Cause Statements:
- Chilled water flow (Ent Wtr Temp)
- Diagnostic 8A
- Chilled water flow (Entering Water Temperature)
- Entering evaporator water temperature sensor is reading colder than leaving water temperature sensor
- Getting an 8A Chilled Water Flow Diagnostic
- Getting a Chilled Water Flow Entering Water temp diagnostic
Facts:
- Air-Cooled Chiller (Pueblo) (RTAA 130-400 Ton)
- Air-Cooled Chiller (Pueblo) (RTAA 70-125 Ton)
- Compressor Chiller (Pueblo) (RTUA)
- Water-Cooled Chiller (Pueblo) (RTWA)
- Sensors have been replaced and read correctly per RTAA-SB-5 checkout
- 1U1 module has been replaced
- Independent sensors placed in a well upstream of the evaporator entering water temp sensor show the chillers' sensor reading two degrees colder than independent sensor
- Sensors have been replaced and read correctly per maintenance manual.
- Control Module Input verified by installing external resistor and verifying the output
- Sensors checked out ok
- Circuit setter valve was set to closed
- Heat tape was energized even though it was 82 degrees outside
- Water temp in evaporator was 98 deg F entering, 135 deg F leaving
- When circuit setter valve was opened and water flowed through the chiller, the water side relief valve popped
Document Identifier: DOC-80521
Document Identifier: 80521
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.