Nor-Lake LogiTemp Walk-In Error Code LSH: Low Superheat

What does Nor-Lake error code LSH mean?

Superheat is a safety margin. It is the number of degrees by which the gas leaving the evaporator is warmer than its boiling point, and that margin keeps liquid refrigerant out of the compressor. The KE2 Evap OEM controller raises LSH when superheat falls below 3F for 5 minutes while the electronic expansion valve is open less than 10 percent. That means the controller has nearly closed the valve and the superheat is still low, so too much liquid refrigerant may be reaching the evaporator and heading toward the compressor. The display shows LSH, and the controller may restrict the valve to protect the compressor. Liquid in the compressor can wash out oil and damage valves, so the alarm matters even when the box is cold. The reasons include the expansion valve and its driver, the accuracy of the suction pressure and temperature sensors, evaporator airflow, including fans and an iced coil, and the refrigerant charge and metering. A coil blocked with ice cannot boil off the refrigerant and gives the same pattern.

Affected models and control systems

This applies to the LogiTemp KE2 Evap OEM controller on Nor-Lake Split-Pak walk-ins with an electronic expansion valve.

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

• LSH on the display
• Frost on the suction line back toward the compressor
• Heavy ice on the coil or a stopped evaporator fan
• Box temperature normal or slightly low

Possible causes

Listed in Nor-Lake's documentation

• Expansion valve or its driver not controlling the flow
• Suction pressure or temperature sensor reading wrongly
• Evaporator airflow problem such as stopped fans or an iced coil
• Refrigerant charge or metering out of balance

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

• Evaporator fan motor failed, so the coil cannot absorb heat
• Suction temperature sensor loose or poorly insulated on the line
• Coil iced over after repeated short defrosts

Safe checks before calling for service

How a technician diagnoses error code LSH

1. Read LSH and the valve opening percentage.
2. Check the evaporator fans and the coil for ice.
3. Compare suction pressure and temperature sensor readings with gauges and a probe.
4. Test the expansion valve and its driver.
5. Check the charge and metering, then confirm superheat settles.

How error code LSH differs from similar codes

HSH is the opposite condition, with superheat too high. LSH means too much liquid is coming through.

Technical reference

Document

LogiTemp Electronic Controller System Operations Manual (171527 Rev. A), Alarms & Notifications List pp. 47-51

Edition

171527 Rev. A, 2025 (Refrigerated Solutions Group)

Models / control

LogiTemp / KE2 Evap OEM (Split-Pak systems, A1 refrigerants)

Section

Alarms & Notifications List, printed pp. 48-52; Troubleshooting Tables from p. 52

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.