Nor-Lake LogiTemp Walk-In Error Code HSH: High Superheat
HSH is the high superheat alarm on a Nor-Lake walk-in with a Split-Pak system and the LogiTemp KE2 controller. In plain terms, the evaporator is not getting enough refrigerant, and the box may run warm. Check the box temperature, move food if it is rising and keep the door closed; do not touch the refrigeration lines.
High: a starved evaporator can leave the box warm and puts stored food at risk.
- Code
- HSH
- Maker
- Nor-Lake
- Equipment
- Walk-in coolers & freezers
- Applies to
- LogiTemp / KE2 Evap OEM (Split-Pak systems, A1 refrigerants)
What does Nor-Lake error code HSH mean?
Superheat is how many degrees the refrigerant gas leaving the evaporator is warmer than its boiling point. A healthy evaporator is nearly full of boiling refrigerant, so superheat stays small. When the coil is starved, the gas warms more before it leaves, and superheat rises. With an electronic expansion valve the controller raises HSH when superheat stays 2F above setpoint for 90 minutes of cumulative run time while the valve is more than 90 percent open, meaning it is wide open and still cannot keep up. With a thermostatic valve it appears when superheat stays above setpoint for 90 minutes. The alarm therefore says the evaporator is not receiving enough refrigerant, and the box may run warm. The reasons lie on the refrigerant side: the charge and the liquid supply to the expansion valve, the valve and its driver, the suction pressure and temperature sensor readings, or a restriction in the liquid line or filter drier.
Affected models and control systems
This applies to the LogiTemp KE2 controller on Nor-Lake walk-ins with a Split-Pak system, with either an electronic or a thermostatic expansion valve. The trigger differs between the two.
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
- HSH on the display
- Box temperature higher than the set point
- Evaporator coil only partly frosted or cold
- Compressor running for long periods
Possible causes
Listed in Nor-Lake's documentation
- Low refrigerant charge or poor liquid supply to the expansion valve
- Expansion valve or its driver not opening correctly
- Suction pressure or temperature sensor reading wrongly
- Restriction in the liquid line or filter drier
Other likely causes — what usually sits behind error code HSH on this control. A technician confirms which one it is before any part is replaced.
- Slow refrigerant leak at a flare or valve core that has lowered the charge
- Filter drier plugged after an earlier repair or moisture event
- Suction temperature sensor loose on the line, so it reads warm
Safe checks before calling for service
- Write down the code and the LED color.
- Check the box temperature with a thermometer and move food if it is rising.
- Keep the door closed and make sure the evaporator fans are turning.
- Do not open any panel or touch the refrigeration lines. Call us to schedule service.
How a technician diagnoses error code HSH
- Read HSH and note the valve type and the valve opening.
- Connect gauges and check suction pressure and temperature.
- Check the charge and look for a leak.
- Check the liquid line and filter drier for temperature drop across them.
- Test the expansion valve and its driver and verify the sensors against reference readings.
- Refrigerant work requires certification and gauges and cannot be done by the operator.
- Valve drivers and sensors connect to live control circuits.
- Superheat must be read together with pressures and temperatures to find the true cause.
How error code HSH differs from similar codes
LSH is the opposite condition, with too little superheat and too much liquid refrigerant.
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.
Related Nor-Lake walk-in cooler & freezer error codes
What does superheat mean for my walk-in?
It is a measure of how well the evaporator is fed with refrigerant. High means it is starved.
Is HSH urgent?
Check the box temperature. If it is rising, move food and call us.
Can I add refrigerant myself?
No. It needs a certified technician, and the cause must be found first.
Need help with Nor-Lake error code HSH?
A technician confirms the cause on site and gives you the price in writing before any work starts.