Service Alert Summary:
Certain geographical regions of the country may experience high voltage phase issue causing an E0 diagnostic error code to display on the unit at start up.
Link to contact Tech Support for help Link for info about Service Alerts
What are known Diagnostics or Symptoms:
EO Diagnostic Error: An E0 error code advises of a 3 Phase voltage issue related to either an incorrect Phase rotation, a Missing phase, a Phase imbalance or an undervoltage / overvoltage condition. It has been determined through testing that the issue is more prevalent in areas of the country where the incoming power source to the unit is inconsistent. This issue is not considered a performance concern with the unit; but rather a condition with the consistency of source power applied to the unit at start up. This inconsistency in source power may cause the units’ controls to lock out the system’s operations not allowing the unit to turn on/run. This system “lockout” is done to protect the unit’s components and subsystems from experiencing premature failures due to the incoming power source issue.
When is this issue currently being observed:
Most E0 error codes have been observed in the 208-230 vac unit range. It is rare to have the E0 error code in the 460 vac unit but is still possible.
This E0 issue has been observed to exist primarily in the High Leg Power Supply configuration. This configuration is typically known as a Wild Leg or Stinger Circuit but is the less common power supply. It typically occurs in areas with older power systems.
Typical voltage readings are measured leg to leg in the 208-230 range. However measured leg to ground the middle leg will measure higher. See examples below:
**Higher voltages are seen on the middle leg with normal voltages on the remaining two legs.
| Example: 208/230 VAC / 3 PH | Example: 460 VAC / 3 PH | |||||
| Leg to Leg | Leg to Ground | Leg to Leg | Leg to Ground | |||
| L1-L2- 208 volts | L1-Gr- 120volts | L1-L2- 460 volts | L1 to Gr- 277 volts | |||
| L1-L3- 208 volts | L2-Gr- 208 volts | L1-L3- 460 volts | L2 to Gr- 415 volts | |||
| L2-L3- 208 volts | L3-Gr- 120 volts | L2-L3- 460volts | L3 to Gr- 277 volts | |||
This has been an on-going concern and has been observed in the past with Variable Frequency Drive (VFD) operation. To resolve this issue, it is recommended to install a Delta-Wye transformer to stabilize the incoming power source when unit startup occurs.
This issue is occurring in the Medium Foundation units because the unit’s control logic is continuously analyzing incoming power voltage to prevent system failure when voltage spikes occur in these geographical areas.
What is the recommended correction currently for the E0 issue:
Testing performed in areas experiencing high rates of E0 error codes revealed that the DC Fan module phase monitor was experiencing the Wild Leg or Stinger Leg voltage spike. This spike was beyond the tolerance limits allowed by the control board and caused the unit to shut down. Further testing was done at jobsites where Delta-Wye transformers had already been installed to correct the incoming voltages. This action corrected the issue but required the end-user to contact the utility provider in the area to address it and, at times, resulted in an additional cost to the customer.
Trane has secured new control boards with software updates that will allow a small expansion of protective voltage tolerances to provide more fluctuations in incoming power while still protecting the unit and its components and subsystems from premature failure. These replacement boards are now available and orderable from Parts Distribution Centers under part numbers BRD08433 (460V) and BRD08434 (208/230V). Please be advised that voltage imbalances that are too severe may not correct this issue. For instances like this, incoming voltage imbalances must be address with the local power agencies.
Issue not addressed by this alert
As with all Trane equipment, the incoming power should meet standard requirements. The issues addressed with this quality alert have been verified to be in the specified voltage ranges.
Below are the Trane standard requirements for all equipment. This information is also included in all equipment IOM with each unit shipped.
Is there a related published service bulletin for this issue?
At this time, we do not expect any bulletin will be published.
Are WMS(Warranty Management System) claims allowed for this issue?
Claims for this issue are currently not allowed.
Does the above information indicate the final resolution?
Yes, final resolution has been confirmed per above.
This document is confidential and proprietary Trane information. Please do not distribute.