HVACopediaTrane · Heat pump
L8 Lockout: high coil temperature
What the control is telling you
Repeated high coil temperature caused a lockout. Manual lists only the meaning (A1000BA board); steps are general checks drawn from other sections of the guide.
Applies to: Trane 5TWR7 multi-speed heat pump (5TWR7024A-060A)
Likely causes
- Dirty outdoor coil or poor airflow
- Overcharge
- Sensor error
Test and repair steps
- Check outdoor coil cleanliness and outdoor airflow (cooling) or indoor airflow (heating).
- Verify charge by subcooling; overcharge raises coil temperature.
- Check the coil sensor reading against actual coil temperature.
Settings for these units
Outdoor unit placement · Trane 5TWR7
| Item | Value |
|---|---|
| Above unit | 5 ft clear |
| Service side | 3 ft |
| Walls / shrubs | 12 in. min |
| Pad | 1 in. larger than unit all round, level, separate from house |
| Cold climate (HP) | raise 3-12 in. above pad |
| Within 1 mile of salt water | add BAYSEAC001 if no factory salt shield |
| Operating range | cooling 55-120 F, heating 0-66 F |
Avoid bedroom walls and under roof drip lines.
Dimensions and weights · Trane 5TWR7
| Model | H x D x W (in.) | Weight (lb) |
|---|---|---|
| 5TWR7024A | 41 x 30 x 33 | 181 |
| 5TWR7036A | 41 x 30 x 33 | 194 |
| 5TWR7048A | 41 x 34 x 37 | 231 |
| 5TWR7060A | 41 x 34 x 37 | 241 |
| 5TTR7024A | 41 x 30 x 33 | 176 |
| 5TTR7036A | 41 x 30 x 33 | 189 |
| 5TTR7048A | 41 x 34 x 37 | 226 |
| 5TTR7060A | 41 x 34 x 37 | 236 |
Weights are estimated, uncrated.
Models that show this code
4 models in Trane 5TWR7
Other codes on the same units
- H8 Hard lock: high coil temperature
- L5 Lockout: drive AC input over-current
- L6 Lockout: high drive IPM temperature
- L7 Lockout: high drive PFC temperature
- FA Outdoor ambient sensor fault
- FC Coil temperature sensor fault
- Fd Discharge temperature sensor fault
- Fr No 24 VAC R signal at outdoor control (heat pump)
Save it for the next call
Star this code in the HVACopedia app and keep the whole library on your phone for jobs with no signal.
Source: Trane ODR-SVN002E-EN (5TTR7/5TWR7 installer's guide) - section Integrated Variable Speed Control Board LED Indicators, Table 18 (A1000BA models). Summarized in our own words; check the original manual for your model.
Homeowner looking at this code? See what it means for you and when to call a technician.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.