Delfield Prep Table Error Code Lo: Low Temperature Alarm
Lo on a Delfield NP prep table is the low temperature alarm, shown alternating with the box temperature every 2 seconds. It applies to refrigerators, which have a low alarm point of 25F (-4C). Check for product freezing and call if it stays on.
Medium: the box is colder than intended, which can freeze product, but the table keeps working.
- Code
- Lo
- Maker
- Delfield
- Equipment
- Prep tables
- Applies to
- 4400/4500 Series NP refrigerated prep tables with R290 temperature control (4424NP-4472NP, D4424NP-D4472NP, ST4424NP-ST4472NP and variants)
What does Delfield error code Lo mean?
The R290 control watches for a box that is too cold as well as too warm. On a refrigerator the factory low alarm point is 25F (-4C). When the box falls below that point, the display switches automatically between Lo and the temperature every 2 seconds. The alarm is delayed in the same way as the high alarm. It sounds and flashes LO 90 minutes after the unit reaches its alarm point, or after any power interruption. Once it starts, it sounds for about 10 seconds, is silent for 50 seconds, and repeats for 15 cycles before going quiet. The code stays on the display until the condition clears. The manual states that freezers have no low alarm point, so Lo is something you will see on a refrigerated table only. Its single listed cause is a box temperature below the low alarm point.
Affected models and control systems
The manual covers the 4400 and 4500 Series NP refrigerated prep tables with the R290 temperature control, including the 4424NP to 4472NP, D4424NP to D4472NP and ST4424NP to ST4472NP sizes and their variants.
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
- Lo alternating with the temperature every 2 seconds
- Alarm tone for about 10 seconds each minute
- Lettuce or sauces beginning to freeze at the back of the pans
- Ice on the pan walls
Possible causes
Listed in Delfield's documentation
- Box temperature below the low alarm point (refrigerator 25F / -4C)
Other likely causes — what usually sits behind error code Lo on this control. A technician confirms which one it is before any part is replaced.
- Thermostat set colder than needed after a recent adjustment
- Cold air from the evaporator blowing straight onto product placed against the rear wall
- Air sensor reading warmer than the real box temperature, so the compressor runs too long
Safe checks before calling for service
- Check the food in the pans for freezing, especially near the back wall.
- Make sure pans are not pushed against the evaporator airflow area.
- Look at the set point on the control display and compare it with your usual setting.
- Wait and watch whether the box temperature rises above the low point within an hour.
- For the service call, note the lowest temperature you measured and the set point.
How a technician diagnoses error code Lo
- Read the code and confirm the box temperature with a calibrated thermometer.
- Check the control's set point and differential against the factory settings.
- Compare the air sensor reading with the thermometer.
- Check that the compressor cycles off, and inspect defrost behavior.
- Confirm the box stays above the low point after adjustment.
- Set point and control parameters are service-level settings that change how the compressor cycles.
- Verifying the air sensor against a thermometer calls for meter checks and, if needed, sensor replacement.
- The refrigeration circuit uses R290, which needs trained handling if any refrigerant work is involved.
How error code Lo differs from similar codes
Lo is the counterpart of Hi. It applies to refrigerators only because freezers have no low alarm point.
Technical reference
- Document
- Prep Tables & Compact Refrigerators, 4400 & 4500 Series: Specifications, Installation, Operation & Maintenance Manual
- Edition
- Part Number 9295093A, 11/25 (page footers 10/25)
- Models / control
- 4400/4500 Series NP refrigerated prep tables with R290 temperature control (4424NP-4472NP, D4424NP-D4472NP, ST4424NP-ST4472NP and variants)
- Section
- Section 3 Operation, control table p. 24 and 'R290 Temperature Alarm' p. 25
- 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 Delfield prep table error codes
Why is my freezer table not showing Lo?
The manual says freezers have no low alarm point.
Will the alarm repeat forever?
It sounds for 15 cycles, then stays silent. The code stays on the display until the condition clears.
What temperature triggers Lo?
On a refrigerator, a box temperature below 25F (-4C).
Need help with Delfield error code Lo?
A technician confirms the cause on site and gives you the price in writing before any work starts.