Kolpak Walk-In Cooler Error Code LOW PRESSURE: Suction Pressure Too Low
LOW PRESSURE means suction pressure dropped below the expected point an excessive number of times. It points to the refrigeration side of the walk-in. Press ENTER to silence the alarm for one hour and have a technician check the charge and pressure controls.
High: repeated low suction pressure affects cooling and can stress the compressor.
- Code
- LOW PRESSURE
- Maker
- Kolpak
- Equipment
- Walk-in coolers & freezers
- Applies to
- ArcticFox OEM Controller with Deluxe Display (Kolpak walk-ins)
What does Kolpak LOW PRESSURE mean?
The ArcticFox controller follows suction pressure on systems that report it. Each time pressure falls below the expected point, the controller adds it to a count. One brief dip is normal and is not reported. When the dips happen an excessive number of times, the controller posts the text alarm LOW PRESSURE in the Alarms menu. The manual does not give the count, the pressure value, or any list of causes, so those details come from the system's own settings. The alarm reflects a pattern in the refrigerant circuit and says nothing about a sensor being shorted or open, since those have their own alarms. The controller keeps running the system. Because low suction pressure can come from several different conditions, the alarm alone cannot name one. It sounds again after the one-hour silence if pressure keeps falling below the expected point.
Affected models and control systems
ArcticFox OEM Controller with Deluxe Display on Kolpak walk-ins that report suction pressure. The manual lists this alarm in the Alarms menu on page 16.
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
- LOW PRESSURE text in the Alarms menu
- Audible alarm from the display
- Room warming slowly or cooling unevenly
- Frost on the suction line or ice on the coil
Possible causes
Likely causes — what usually sits behind LOW PRESSURE on this control. A technician confirms which one it is before any part is replaced.
- Refrigerant charge low from a slow leak, so suction pressure keeps dropping
- Evaporator coil iced over or fans blocked, starving the compressor of heat load
- Expansion valve restricting flow more than the load needs
- Suction pressure transducer drifting so it reads lower than actual
Safe checks before calling for service
- Press ENTER to silence the alarm for 1 hour. It sounds again if suction pressure keeps dropping.
- Check that product is not stacked against the evaporator and that the door closes fully.
- From outside, look for heavy frost on the visible coil. Do not open panels.
- Tell the technician the alarm text, how long it has appeared, and whether the room has been warm.
How a technician diagnoses LOW PRESSURE
- Read the pressure setpoints and the count threshold from the controller.
- Fit gauges and compare suction pressure with the transducer reading.
- Check the evaporator for ice, fan operation and airflow.
- Check charge, superheat and the expansion valve.
- Repair the cause and confirm suction pressure holds above the expected point through several cycles.
- Gauge readings and charge checks are done on the refrigerant circuit under license rules.
- Evaporator fans and defrost heaters are live circuits behind panels.
- Valve and charge adjustments without measurement can damage the compressor.
Technical reference
- Document
- ArcticFox Deluxe Display - Original Instructions, Installation, Operation and Maintenance Manual
- Edition
- Part No. 500002385-4, 5/23
- Models / control
- ArcticFox OEM Controller with Deluxe Display (Kolpak walk-ins)
- Section
- ArcticFox OEM Controller - Alarms Menu, p.16
- 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 Kolpak walk-in cooler & freezer error codes
Is LOW PRESSURE the same as a refrigerant leak?
Not always. A leak is one cause, but a frozen coil or a drifting pressure sensor can show the same alarm.
Can the walk-in keep running?
Usually yes, but low suction pressure can reduce cooling, so have it checked soon.
How is this different from SHORT COMP CYCLE?
This alarm counts pressure drops below the expected point. SHORT COMP CYCLE counts compressor starts.
Need help with Kolpak LOW PRESSURE?
A technician confirms the cause on site and gives you the price in writing before any work starts.