Marvel Bar Refrigerator Error Code Lo: Cabinet Too Cold
Lo on a Marvel MicroSentry II refrigerator means the cabinet temperature stayed below the set point for more than 60 minutes. Check the set point, move product away from the back wall, and confirm the cabinet temperature with a thermometer. Call us if it stays colder than set point.
Medium: product can freeze or chill too far, but the unit is cooling.
- Code
- Lo
- Maker
- Marvel
- Equipment
- Bar refrigeration
- Applies to
- Marvel MicroSentry II
What does Marvel error code Lo mean?
Lo on Marvel MicroSentry II refrigerators such as the MS24RA and SA24RA means the cabinet temperature stayed below the set point for more than 60 minutes. The cabinet is colder than it should be, so bottles, fruit or other stock can freeze or chill too far. A changed set point or a sensor reading off are the usual first suspects. The control compares the cabinet reading with the set point and starts the one-hour count when it is too cold, then sounds the alarm when the count ends. The manual lists the set point and recent setting changes, the accuracy of the temperature sensor, the control output to the compressor, and product touching the back wall. The display text is Lo, with a capital L. If someone adjusted the set point and the cabinet is cold only on a part of a shelf, the cause is likely simple. A cabinet that is cold everywhere with a correct set point needs a technician.
Affected models and control systems
Marvel MicroSentry II scientific refrigerators, such as the MS15RA, MS24RA and SA24RA. Lo is specific to this control's low-temperature alarm.
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
- Beeping and Lo on the display
- Bottles or fruit chilled too far or starting to freeze
- Frost on the back wall
- Compressor running more than normal
Possible causes
Listed in Marvel's documentation
- Set point changed or set too low
- Temperature sensor reading wrong
- Control output keeping the compressor running
- Product touching the back wall
Other likely causes — what usually sits behind error code Lo on this control. A technician confirms which one it is before any part is replaced.
- A set point lowered by someone trying to cool a load faster and never put back
- A sensor that reads warmer than the real cabinet and keeps the compressor on
- A compressor relay that sticks closed and keeps cooling
Safe checks before calling for service
- Check the set point and confirm nobody changed it.
- Move product away from the back wall.
- Check the cabinet temperature with a thermometer.
- Call us if the cabinet stays colder than set point, and tell us where the coldest spot is.
How a technician diagnoses error code Lo
- Read the set point and compare with a thermometer in the cabinet.
- Check the sensor reading against the real temperature.
- Observe whether the compressor cycles off at set point.
- Inspect the relay or control output to the compressor.
- Replace the sensor or control part that the test proves bad.
- Control output and relay testing need meter work on live circuits.
- Sensor accuracy depends on comparing resistance with a chart.
- Frozen product may need disposal, which is a call for the owner.
How error code Lo differs from similar codes
Lo is the cold counterpart of hi, but the usual first suspects are the set point and sensor rather than airflow.
Technical reference
- Document
- 41014158 Rev J p.7
- Maker documentation
- Marvel owner support
- Edition
- 41014158-EN Rev J
- Models / control
- Marvel MicroSentry II
- Section
- Using the MicroSentry II Control - Alarms and Alarm Mute, printed p. 7 (PDF p. 7)
- 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 Marvel bar refrigeration error codes
Can I keep using the refrigerator with Lo?
Yes, but move delicate stock away from the back wall and watch for freezing.
Will Lo clear by itself?
It clears once the temperature returns near the set point. If the setting or sensor is wrong, it returns.
Is Lo the same as hi?
No. Lo is too cold for an hour, while hi is too warm for an hour.
Need help with Marvel error code Lo?
A technician confirms the cause on site and gives you the price in writing before any work starts.