Nor-Lake LogiTemp Walk-In Alarm LPA: Low Pressure

What does Nor-Lake error code LPA mean?

The suction side of a refrigeration system should hold a working pressure while the compressor runs. The LogiTemp KE2 controller watches suction pressure and has a cut-out value below which the compressor should not keep operating. LPA means pressure is below that cut-out even though the controller keeps trying to run the compressor. The system cannot build the pressure it needs, so cooling is poor or absent. Possible causes include low refrigerant, a restricted line, a stuck valve or a pressure sensor that reads wrong. A refrigerant leak is the first suspect, because less refrigerant means less pressure, and the signs are often frost at the wrong spots or oil traces near joints. A restriction at the liquid line or filter drier starves the evaporator in a similar way, while a sticking expansion valve can do the same from the metering side. A sensor that reads low when the real pressure is fine gives the same alarm, so the reading has to be verified with gauges. Food in the walk-in can warm quickly if LPA persists.

Affected models and control systems

This applies to the LogiTemp KE2 controller on Nor-Lake walk-in coolers and freezers with a Split-Pak system.

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

• LPA on the display
• Compressor cycling or not running
• Box temperature rising
• Evaporator coil warm or only slightly frosted

Possible causes

Listed in Nor-Lake's documentation

• Low refrigerant charge or a leak
• Restriction in the liquid line or filter drier
• Expansion valve not operating correctly
• Suction pressure sensor reading wrongly

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

• Slow leak at a flare joint or service valve cap
• Filter drier clogged with debris after a compressor change
• Pressure sensor line kinked or its fitting loose

Safe checks before calling for service

How a technician diagnoses error code LPA

1. Read LPA and the suction pressure and box temperature.
2. Connect gauges and compare with the controller reading.
3. Look for leaks with a detector at joints and valves.
4. Check the liquid line, filter drier and expansion valve.
5. Repair the leak or restriction, recharge by weight, and confirm pressure and cooling return.

How error code LPA differs from similar codes

Pdt also concerns low-pressure control, but at pump-down. LPA means the suction pressure is already below the cut-out.

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.