Issue:
DIAGNOSTIC: bE8, oil flow switch closed
Resolution:
RTHA
If the 4S5 oil flow switch is closed before start-up, bE8 diagnostic is displayed. This checks for an oil flow switch that is not functioning properly. When changing from an oil flow switch to a differential pressure switch, transition complete input (1TB4-5,6) is looked at. If this input is seen to be closed at start up, the bE8 diagnostic will be displayed. Verify this input is open at start up (check RUN Contactor AUX contacts).
If the chiller has been retrofitted from a flow switch to a D/P switch and is wired properly, this alarm should not show up. The wiring in RTHA-SB-19, page 4, figure 1, shows the proper wiring for the differential pressure switch retrofit. If the BE8 alarm is flashing between BE8 and A72, move the jumper from 1TB4-1 to 1TB4-2. This should clear the BE8 alarm, but only if the chiller is without active oil return.
The problem can be confusing since the diagnostics are different from the original ones. The changes to the oil DP switch from the oil sensing switch are described in RTHA-SB-11.
Notes:
Refer to RTHA-SB-5 and RTHA-SB-19 for troubleshooting and additional information.
See literature order number RLC-EB-9 for information on the operation of active oil return.
Changes:
Other Question/Problem/Cause Statements:
- DIAGNOSTIC: bE8, oil flow switch closed
Facts:
- Water-Cooled Chiller (Pueblo) (RTHA)
- Differential pressure switch installed instead of an oil flow switch
Document Identifier: DOC-83549
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.