Applicable Systems
TransSteel 2700
Symptoms
The Fronius power source displays the over-temperature service code 'to', indicating the control circuit temperature has exceeded the rated limit. The welding output is disabled.
Possible Causes
- Duty cycle exceeded for the selected welding current
- Cooling fan blocked or not functioning
- Ambient temperature too high around the power source
- Heat sink or cooling fins clogged with dust and debris
Troubleshooting Steps
- Step 1: Allow the power source to cool down naturally
Wait until the over-temperature indicator turns off before resuming welding - Step 2: Check and clean cooling fan and air inlet/outlet louvers
Air passages must be clear; use compressed air to clean dust buildup - Step 3: Verify ambient temperature does not exceed 40C
If ambient temperature is high, improve ventilation or move power source - Step 4: Reduce welding current or duty cycle to stay within rated limits
Check duty cycle rating on the nameplate for the current setting
How to Reset
To reset: 1) Allow the power source to cool. 2) The over-temperature code will clear automatically. 3) Resume welding at a lower duty cycle or current. Caution: Repeated over-temperature events can permanently damage internal components.
Frequently Asked Questions
- Q: What does service code 'to' mean on Fronius welders?
The 'to' code indicates over-temperature in the control circuit. The power source has exceeded its thermal limits and output is disabled until it cools.
- Q: How long does it take for the 'to' code to clear?
Cooling time depends on ambient temperature and the degree of overheating. Typically 5-15 minutes. Do not force a restart.
Source: Fronius Perfect Welding Operating Instructions, Service Codes, Document 42,0426,0076
Category: Welding