Polar King Walk-In Cooler Alarm PRESSURE SENSOR: Out of Range
PRESSURE SENSOR is an alarm on the KE2 evaporator control of a Polar King walk-in: the suction pressure sensor is shorted, open or reading out of range. The document gives no repair steps. Note the alarm, check that the cooler is holding temperature, and have it looked at if the alarm returns after clearing.
Medium: a sensor input is invalid, though the document does not describe a shutdown.
- Code
- PRESSURE SENSOR
- Maker
- Polar King
- Equipment
- Walk-in coolers & freezers
- Applies to
- Polar King walk-in coolers/freezers with KE2 Evaporator Efficiency Evap OEM board (Basic Display / Combo Display)
What does Polar King PRESSURE SENSOR mean?
The KE2 Evaporator Efficiency board on a Polar King walk-in reads suction pressure from a sensor on the refrigerant line, along with several temperature sensors. When the pressure sensor circuit is shorted or open, or when the pressure it reports is out of range, the board records PRESSURE SENSOR. On the Combo Display you see the words in the Alarms menu; on the Basic Display you see only a red or yellow alarm light. The Alarms Status Menu in the installation instructions is view only: it lists the alarm and states what triggers it, which is a shorted sensor, an open sensor or an out-of-range pressure. The document gives no causes and no repair steps. It says alarms can be cleared with the CLEAR ALARMS manual-menu item. Superheat is normally worked out from suction pressure and suction temperature, so this alarm is worth taking seriously even though the document does not explain its effects.
Affected models and control systems
Polar King walk-in coolers and freezers fitted with the KE2 Evaporator Efficiency Evap OEM board, with either the Basic Display or the Combo Display. The alarm is listed in the Alarms Status Menu, which is view only, on page 14 of the KE2 installation instructions.
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
- Red or yellow alarm light on the Basic Display
- PRESSURE SENSOR listed in the Alarms menu of the Combo Display
- Evaporator control not behaving normally
- Walk-in temperature drifting
Possible causes
Likely causes — what usually sits behind PRESSURE SENSOR on this control. A technician confirms which one it is before any part is replaced.
- A pressure sensor cable damaged where it runs along the refrigerant line
- Oil or moisture at the sensor fitting after service
- A sensor connector at the board that has loosened
Safe checks before calling for service
- Note whether the light is red or yellow, and if you have the Combo Display, read the alarm name in the Alarms menu.
- Check the walk-in temperature with a thermometer.
- Clear the alarm with the CLEAR ALARMS menu item, as the document says, and see whether it comes back.
- If PRESSURE SENSOR returns, write down the time and the walk-in temperature and arrange service.
How a technician diagnoses PRESSURE SENSOR
- Read the active alarm and history on the Combo Display.
- Compare the displayed pressure with a gauge on the suction line.
- Check the sensor wiring and connector for a short or open circuit.
- Verify the sensor supply and signal at the board with a meter.
- Replace the sensor or board only after the gauge and meter readings show which one fails.
- Checking suction pressure requires refrigerant gauges and certification. The sensor wiring terminates at an evaporator board with live control wiring nearby. The document is only a status listing, so a technician has to apply refrigeration knowledge to find the cause.
How PRESSURE SENSOR differs from similar codes
PRESSURE SENSOR is the only alarm in this list that concerns pressure; T1 to T4 concern temperature sensors.
Technical reference
- Document
- KE2 Evaporator Efficiency Installation Instructions N.1.1 (posted on polarking.com Downloads as ke2-installation.pdf; authored by KE2 Therm Solutions)
- Edition
- N.1.1 July 2015
- Models / control
- Polar King walk-in coolers/freezers with KE2 Evaporator Efficiency Evap OEM board (Basic Display / Combo Display)
- Section
- Alarms Status Menu (view only), p. 14 (Alarm Status Menu listed p. 13)
- 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 Polar King walk-in cooler & freezer error codes
Can I keep using the walk-in with this alarm?
The document does not say the cooler stops. Watch the box temperature closely and protect product if it rises.
Does CLEAR ALARMS fix the problem?
It only clears the stored alarm. If the sensor circuit is still bad, the alarm will return.
Why does the Basic Display show only a light?
The Basic Display has no text. Only the Combo Display lists the alarm name.
Need help with Polar King PRESSURE SENSOR?
A technician confirms the cause on site and gives you the price in writing before any work starts.