Delfield Prep Table Error Code E04: Sensor 4 Defect
E04 on a Delfield NP prep table means the control reports a defect in sensor 4. The manual's comments column for this row reads Open and does not name which sensor it is.
Medium: a sensor input has failed and the manual does not say what it affects.
- Code
- E04
- 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 E04 mean?
On the R290 control, each temperature input has its own code, and E04 belongs to sensor 4. When the control gets no valid reading from that input it displays E04 in place of the temperature. The manual's control table lists it as sensor 4 defect with the comment Open. As with E03, the table does not say which sensor this is or what part of the table it watches. The manual offers no cause beyond the sensor itself and no action for the operator. Because the table is silent, a page about E04 can only say what the control reports and recommend that you keep checking food temperature while a technician identifies the input. A technician would normally trace the lead from the control to the sensor on your own table, since the layout depends on the size and variant. The listed models include standard, D and ST variants.
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
- E04 on the display
- Temperature reading replaced by the code
- Cooling continuing as before
- Code returning after a power reset
Possible causes
Listed in Delfield's documentation
- Sensor 4 reported defective, with the manual's comments column showing Open
Other likely causes — what usually sits behind error code E04 on this control. A technician confirms which one it is before any part is replaced.
- Sensor wire damaged where it passes through the cabinet or hinge area
- Loose connector at the control or at the sensor
- Water getting into the sensor lead during cleaning
Safe checks before calling for service
- Use a separate thermometer in the food to check it is still cold enough.
- See whether the code is on all the time or only after the unit restarts.
- Do not open the unit or pull on cables.
- Make sure nothing has been stacked on or against the cabinet in a way that might pinch a sensor lead.
- For the service call, write down E04, the model and your own temperature reading.
How a technician diagnoses error code E04
- Read E04 and any other sensor codes on the display.
- Identify sensor 4 from the wiring diagram for that model.
- Check the sensor lead and connector, then measure the circuit with a meter for an open condition.
- Try a known-good sensor in its place to separate a sensor problem from a control problem.
- Replace the part that fails the test and confirm the temperature reading returns.
- Identifying sensor 4 requires the model's wiring diagram, because the manual does not name it.
- Meter checks on the sensor circuit are done with power off at the unit.
- Swapping parts without testing can leave the display code unchanged and cost another visit.
How error code E04 differs from similar codes
E04 is the highest numbered sensor code in the table. Like E03, the manual leaves sensor 4 unnamed.
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
Do I need to stop using the table?
The manual does not say. Check product temperature yourself and call if it is not holding.
Is E04 related to E03?
They are different sensors, and the manual treats both the same way, with Open in the comments.
Will it clear on its own?
The manual does not say; it lists only the indication.
Need help with Delfield error code E04?
A technician confirms the cause on site and gives you the price in writing before any work starts.