Delfield Prep Table Error Code E01: Air Sensor Defect
E01 on a Delfield NP prep table means the control reports a defect in sensor 1, which the manual's table marks as the air sensor. The manual lists only the indication. If you are unsure how the control should behave, it directs you to Delfield Technical Support at 1-844-724-CARE.
Medium: the control has lost its box temperature reading, so cooling may be off while the unit still runs.
- Code
- E01
- 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 E01 mean?
The R290 temperature control in a Delfield NP prep table reads temperature sensors and uses those readings to decide when the compressor runs and when it defrosts. Sensor 1 is the air sensor that tells the control the temperature inside the food box. When the control cannot get a valid reading from it, the display shows E01 in place of the temperature. The manual's control table says sensor 1 defect and marks it as the air sensor in the comments column. It does not list a cause for the defect beyond the sensor failing, and it gives no operator steps. That is the whole of what the manual states about E01, so this page does not guess at wiring or board causes. Because the air sensor is what the control relies on for box temperature, it is worth watching the food temperature with your own thermometer until the code is cleared. The manual's only direction is to contact Technical Support if unsure of the control function.
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
- E01 shown instead of the box temperature
- Product temperature not matching what the display used to show
- Compressor running longer or shorter than usual
Possible causes
Listed in Delfield's documentation
- Sensor 1, the air sensor, reported defective
Other likely causes — what usually sits behind error code E01 on this control. A technician confirms which one it is before any part is replaced.
- Sensor probe damaged by a cleaning tool or crushed where the cable runs
- Sensor connector at the control loose after the unit was moved or serviced
- Moisture at the sensor lead from a wash-down
Safe checks before calling for service
- Check the temperature of the food in the pans with a separate thermometer, and move any product at risk.
- Look at the unit for visible damage to the air sensor lead where you can see it from outside, without opening panels.
- Note whether E01 is steady or comes and goes.
- Do not open the control housing. The manual gives no operator reset for E01.
- For the service call, write down E01, the unit size, how long it has shown, and the box temperature on your thermometer.
How a technician diagnoses error code E01
- Read E01 and check whether any other sensor code is also present.
- Check the air sensor lead and connector for damage, corrosion or a loose pin.
- Measure the sensor resistance with a meter and compare with its temperature using the manufacturer's chart.
- Swap in a known-good sensor to confirm whether the control or the probe is at issue.
- Verify box temperature with a calibrated thermometer after the repair.
- The sensor lead runs to the control, which carries line voltage, so connections are tested with power disconnected.
- Reading sensor resistance against a temperature chart needs a meter and the manufacturer's values.
- If the probe is fine, the diagnosis moves to the control, which a technician has to confirm before replacing.
How error code E01 differs from similar codes
E01 and E02 are both sensor codes on this control: E01 is the air sensor and E02 is the coil sensor. E03 and E04 are listed as sensors 3 and 4.
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, 'R290 Temperature Control & Display' table, p. 23-24
- 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
Can I keep using the prep table with E01 showing?
The manual does not say. Watch the food temperature with your own thermometer, and call if it drifts.
Does E01 clear itself?
The manual does not say. It lists the indication only.
Is E01 the same as E02?
No. The manual marks E01 as the air sensor and E02 as the coil sensor.
Need help with Delfield error code E01?
A technician confirms the cause on site and gives you the price in writing before any work starts.