Trane Rooftop Troubleshooting & Error Codes
Trane rooftop air conditioners like the Voyager 1 YSD series and Precedent YSC series are known for their efficiency and dependability. In the rare case there’s a problem with your unit, this Trane rooftop troubleshooting and error codes guide explains the meaning of the LED lights and possible causes for why your unit is noisy or isn’t working.
This information is for Trane Voyager 1 rooftop units, such as the YSD series, as well as Precedent™ packaged rooftop units, including the YSC series.
Safety Warning: Before Troubleshooting Trane Rooftop Units
Servicing rooftop HVAC equipment involves electrical, mechanical and environmental hazards. To reduce the risk of injury, equipment damage, or system failure, follow these safety precautions before any troubleshooting or maintenance:
- Disconnect the power first
- Authorized service technicians should handle condenser/evaporator coil maintenance
- Ensure all moving parts have come to a complete stop before working inside the unit
- Use proper PPE when inspecting or servicing rooftop units
- Follow manufacturer guidelines and always refer to the manufacturer’s service manual
Why is My Trane Rooftop Unit Not Working?
If the unit is failing to cool or heat your building, check for the following causes to repair:
- Circuit breaker is off or tripped - Turn on or reset the breaker.
- Air filter is dirty or damaged - Clean or replace the filter depending on if your unit uses replaceable ones.
- Condenser coil is dirty - Contact an authorized service technician to clean and inspect the coil.
- Thermostat is set to the wrong setting - Adjust the thermostat to HEAT or COOL depending on what you need it to do.
- Thermostat temperature is too high or low - Adjust the temperature to something more comfortable for your space.
- Returns are dirty - Dust or vacuum the returns.
What Causes a Trane Rooftop Unit to Make Noise?
A noisy unit can be irritating for customers to listen to. Determine what sound you’re hearing and consult our possible fixes for them:
Whistling
- Air filter is dirty or damaged - Clean or replace the filter depending on if your unit uses replaceable ones.
- Belts are worn out - Contact an authorized service technician to replace them.
- Returns are dirty - Dust or vacuum the returns.
Semi-Loud Buzzing
This sound typically occurs when the unit starts running. However, if the buzzing is louder than usual, contact an authorized service technician to verify there isn’t another issue occurring.
What Do These Trane Error Codes Mean?
Any testing or repairs outlined in this portion of the guide will need to be completed by an authorized technician.
LED 1 Is Off - System Failure
The voltage between terminals 6 and 9 on J6, the Refrigeration Module (RTRM), should be approximately 32VDC. If no voltage is present, replace the RTRM.
LED 2 Is Off Or Flashing - Heating Failure
If there’s an issue with the heating system, the number of flashes indicates the cause:
- Light is on - Normal operation
- Light is off - No power or failure
- Light is flashing slowly - Normal operation or heat call
- 1 flash - Communication failure
- 2 flashes - System lockout
- 3 flashes - Pressure switch failure
- 4 flashes - TC01 or TC02 open
- 5 flashes - Flame without gas valve
- 6 flashes - Flame rollout open (Trane Voyager 1 models only)
LED 3 Is Flashing - Cooling Failure
If LED 3 is flashing, there’s an error with the cooling system. There are many possible causes:
- Cooling and heating set point (slide pot) on the zone sensor have failed.
- Zone temperature thermistor ZTEMP on ZTS has failed.
- CC1 or CC2 24 VAC control circuits are open.
- LPC1 has opened on time within the 3-minute minimum during 4 consecutive compressor starts.
LED 4 Is Off Or Flashing - Service Failure
- Light is off - Clogged filter switch has closed.
- Light is flashing - Supply fan proving switch has closed.
If you need more information on how to care for your unit, the large library of Trane manuals on our site is a helpful resource.