Federal Display Refrigerator Error Code E2: Coil Probe

What does Federal Industries error code E2 mean?

The Ranco E72R control watches the evaporator coil through a probe, and it uses that reading to manage defrost. When the probe circuit is open or shorted, the control can no longer tell what the coil is doing and shows E2. The manual's wording is plain: the evaporator coil probe is open or shorted and needs replacing. It lists that single cause and that single action. It gives no timing and no resistance value, and it does not describe what the case does while E2 is displayed. Because the probe is on the coil, which is inside the case, the operator cannot reach or test it. What can be done from outside is noting the model and whether the control shows E2 steadily or only sometimes, since an intermittent reading may point to a loose connection rather than a sound probe that failed outright.

Affected models and control systems

RSSM360/RSSD360, RSSM460/RSSD460, RSSM560/RSSD560, RSSM660/RSSD660, and RSSM378/RSSD378 to RSSM678/RSSD678 self-contained and remote display cases, including drop-in, MLK and NSSM, with the Ranco E72R control.

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

• E2 on the controller display
• Defrost that does not run or runs at the wrong time
• Frost building on the coil or a warm case

Possible causes

Listed in Federal Industries's documentation

• Evaporator coil probe open or shorted

Other likely causes — what usually sits behind error code E2 on this control. A technician confirms which one it is before any part is replaced.

• A probe lead pinched or cracked where it crosses the coil area
• A probe that has been damaged by ice or by a defrost heater
• A connector at the control with a poor contact

Safe checks before calling for service

How a technician diagnoses error code E2

1. Confirm E2 and the control type (Ranco E72R).
2. Inspect the probe lead and its connection at the control with power off.
3. Measure the probe's resistance and check for an open or short against the maker's table.
4. Replace the evaporator coil probe, as the manual says.
5. Restore power and confirm the case defrosts and E2 stays clear.

How error code E2 differs from similar codes

E2 on the Ranco E72R is the evaporator probe. Other controllers, such as the Carel unit listed in the same manual, use their own codes.

Technical reference

Document

Installation & Operation Instructions E3496, RSSM/RSSD (with Ranco/Carel controller)

Maker documentation

Federal Industries owner support

Edition

REV L 5/14/24

Models / control

RSSM360/RSSD360, RSSM460/RSSD460, RSSM560/RSSD560, RSSM660/RSSD660, RSSM378/RSSD378 to RSSM678/RSSD678, self-contained and remote (incl. Drop-in, MLK, NSSM), Ra

Section

Control description, 'Error Codes' (printed pp.11-12; PDF p.15), 'Ranco control' list

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.