Flash code 3 on a Copeland Scroll Digital Compressor Controller means the controller is calling for the compressor, but the compressor is off and drawing no current, according to Trane's support article. Read the codes on the controller and the protection module first. Then check the protection module, limits, switches, breaker and contactor before you power-cycle.
What flash code 3 means
Trane's support article, "What does a flash code 3 mean on a Copeland Scroll Digital Compressor Controller," describes the condition in one line. The controller has a call for the compressor. The compressor is not running, and the controller sees no current. The code does not name a failed part. It tells you the call is present and the compressor is not responding to it.
That makes the fault a "what is stopping it" question, not a "what failed" question. The article lists the places to look, and none of them is the controller itself. Each item on the list sits between the call and the compressor, so the work is to find which one is stopping the start.
Trane's article names both the digital scroll controller and the compressor protection module, and says the protection module is located in the compressor junction box. Record the codes from each before you compare them.
Why you should not power-cycle first
Trane's guidance is to check the codes on both the controller and the protection module before you power-cycle. Per Trane, whenever power is cycled off and on, the current flash code and all internal counters are reset. Check first, because the codes you would have read are cleared by the cycle.
Important: Record both devices' codes and their order before you touch the power. Photograph the controller and the protection module if you can.
What Trane lists as possible causes
- A protection module that has tripped
- An open discharge-line high limit
- An open high-pressure or low-pressure switch
- A tripped breaker
- An open contactor coil
- A contactor that is sticking
- A loose wire
Trane's article gives these as causes of the condition. It does not rank them. We do not rank them either.
What to check, in order
- Read and record the controller code. Note the flash count and whether the controller shows any other code.
- Read and record the protection module code. Trane places the module in the compressor junction box. Record what it shows before you do anything else.
- Confirm the call for the compressor. The condition only applies when the controller is calling. Verify that the call is present at the controller.
- Check the breaker and disconnect. A tripped breaker is on Trane's list and is the quickest item to rule in or out.
- Check the high-pressure and low-pressure switches. Note whether each is open or closed. Compare any open switch against the actual system pressures on gauges before you decide whether the switch or the system is the problem.
- Check the discharge-line high limit. An open limit is on Trane's list. Note whether it is open or closed, and compare that to the actual discharge conditions before you decide the limit is at fault.
- Check the contactor coil and the contactor. Is the coil energized? Do the contacts close when it is? An open coil and a sticking contactor are both on Trane's list.
- Check the wiring. Look for loose terminals and connectors along the control and power path.
- Power-cycle last. Only after you have recorded both devices' codes and worked through the list.
Steps 3, 5, 6 and 8 add generic trade practice to the causes Trane lists. We give no voltage, resistance or pressure values here because none appear in the source we reviewed.
After you find the cause
Once you correct the condition, restore the call and watch for the compressor to start and draw current. Then read the controller and the protection module again. A code that returns after the repair means there is another cause on Trane's list still in the way.
Do not jumper a high-limit or a pressure switch to get past the code. An open limit or switch is doing its job until you know why it is open, and the "why" is the finding. If a switch is open at normal system pressures, the switch or its wiring is the suspect. If it is open at abnormal pressures, the system is.
What to send us
- The unit model and serial number
- The compressor model from its nameplate
- The controller and protection module labels
- The flash counts you recorded on each device
- A photo of the part you want to replace
Parts in this circuit
| Component | Role in this issue | Where to find it |
|---|---|---|
| Digital compressor controller and protection module | Show the codes; the protection module is on Trane's cause list | Controls |
| Scroll compressor | The load that is off with no current | Copeland Scroll Compressors |
| Contactor | An open coil or a sticking contactor is on Trane's cause list | Send the unit model and the existing contactor details through contact |
| High-pressure and low-pressure switches, discharge-line high limit | Any of them open is on Trane's cause list | Send the unit model and the existing switch details through contact |
| Trane parts | Trane-branded listings | Trane Replacement Parts |
Our Trane replacement parts collection is where Trane-branded listings sit. It is not a list of digital compressor controller parts. We do not list a Copeland digital compressor controller or protection module by title. If you need one, send the model and serial number of the unit and the device label through the contact page.
Scope: This covers the Copeland Scroll Digital Compressor Controller as described in Trane's support article. It does not cover other controllers. Comfort Alert modules use their own codes: on a Comfort Alert module, code 3 means short cycling, according to Copeland's Comfort Alert troubleshooting guide. CoreSense modules use different codes again. Use the document for the device on your unit.
Before you order
Confirm your unit's exact model and serial number from its nameplate, and the compressor model from the compressor nameplate, before ordering. Search the part number in our site search, browse the Copeland scroll compressors collection and the compressors collection, and read our guide to finding the correct part from the model and serial number. To confirm fit, contact us or email help@totalhvacparts.com with your model and serial number.
Frequently Asked Questions
What does flash code 3 mean on a Copeland Scroll Digital Compressor Controller?
Per Trane's support article, the controller is calling for the compressor, but the compressor is off and no current is detected. The code does not name a failed part. Check the protection module, limits, switches, breaker and contactor.
Why should I not power-cycle the compressor controller?
Trane says to check the codes on the controller and the protection module first. Cycling power resets the flash code and the controller's internal counters, which removes the history you would use to find the cause.
Compressor called but no current: what causes it?
Trane lists a tripped protection module, an open discharge-line high limit, an open high-pressure or low-pressure switch, a tripped breaker, an open contactor coil, a sticking contactor and a loose wire.
Is flash code 3 the same on a Comfort Alert module?
No. Copeland's Comfort Alert troubleshooting guide lists code 3 as short cycling. That is a different device with its own code table. Use the document for the module installed on your unit.
Sources
- Trane support article, "What does a flash code 3 mean on a Copeland Scroll Digital Compressor Controller," support.trane.com
- Copeland Comfort Alert troubleshooting guide (code 3 reference in the scope note only)
Compressor and control-circuit work involves line-voltage electrical components, stored charge, refrigerant under pressure and hot surfaces. Service should be performed only by qualified personnel, following the equipment manufacturer's instructions and your facility's lockout/tagout procedures.