Turbo Air Refrigerator Display Lo / Hi: Temperature Out of Range
On Turbo Air TSR refrigerators and TSF freezers with the 88 LED controller, Lo and Hi mean the inside temperature is outside the display range. Close the door, compare the display with a thermometer, and move perishable food if the cabinet is warm.
Medium: a Hi reading means the cabinet is far too warm and food is at risk.
- Code
- Lo / Hi
- Maker
- Turbo Air
- Equipment
- Reach-in refrigerators
- Applies to
- TSR/TSF 88 LED controller
What does Turbo Air error code Lo / Hi mean?
The display shows Lo when the inside temperature is below minus 50 F and Hi when it is above 50 F, as on the TSR-49SD-N6 and TSF-49SD-N. These are the limits of what the display will show. A Hi on a refrigerator means it is far too warm. A Lo can mean a sensor problem, since the cabinet cannot normally be that cold. Whichever appears, the first step is to put a thermometer in the cabinet and compare. If the cabinet really is warm, the causes are the ones that trap heat: a door that does not seal, a dirty condenser, a stalled fan, or an iced evaporator that stops cold air from reaching the box. If the box is fine and the display shows Lo, a sensor reading far wrong is the likely cause.
Affected models and control systems
Turbo Air TSR refrigerators and TSF freezers with the 88 LED controller, such as the TSR-49SD-N6 and TSF-49SD-N.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- Hi or Lo instead of a temperature
- Cabinet obviously warm with Hi
- Cabinet fine but display shows Lo
- Frost or ice on the evaporator cover
Possible causes
Listed in Turbo Air's documentation
- A door that does not seal, letting warm air push the display to Hi
- A dirty condenser or stalled fan that keeps heat inside the cabinet
- An iced evaporator that stops cold air from reaching the box
- A cabinet sensor that reads far wrong, which can show Lo
Other likely causes — what usually sits behind error code Lo / Hi on this control. A technician confirms which one it is before any part is replaced.
- A door left propped during a delivery
- A sensor wire shorted so it reads an extreme value
- A condenser grille blocked by stock stored in front of it
Safe checks before calling for service
- Close the door and check that it seals.
- Compare the display with a thermometer placed inside.
- Move perishable food to another cooler if the cabinet is warm.
- Clear dust around the condenser if it is easy to reach.
- Call us to schedule service if the display stays on Lo or Hi.
How a technician diagnoses error code Lo / Hi
- Verify actual temperature with a calibrated thermometer.
- Check gasket, door fit and condenser airflow.
- Check condenser and evaporator fans.
- Look for an iced evaporator and check defrost.
- Test the cabinet sensor for a short or open against a reference.
- Replace the sensor or address the cooling issue after the test.
- Fan and sealed-system work involves live wiring and refrigerant.
- A sensor reading far off needs a meter and a reference.
- Defrost and heater tests are at full line voltage.
Technical reference
- Document
- TSR/TSF Service Manual, 5-1-2 Error display
- Models / control
- TSR/TSF 88 LED controller
- Section
- 5. Electronic Controller Instruction - 5-1-3 Error Code Table (TSF freezer controller, PDF p. 20) and 5-2-3 Error Code Table (TSR refrigerator controller, PDF p. 24); display codes also PDF p. 19-20 (page numbers are PDF page numbers, the pages carry no printed numbers)
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related Turbo Air reach-in refrigerator error codes
Does Lo mean the cabinet is actually minus 50 F?
Probably not. It more likely means the sensor reads far wrong.
Does Hi mean the food is spoiled?
Check the food with a thermometer. Hi means the cabinet is very warm.
What clears it?
Fixing the cause; the display returns to normal once the temperature or sensor is back in range.
Need help with Turbo Air error code Lo / Hi?
A technician confirms the cause on site and gives you the price in writing before any work starts.