FR FieldReady Academy
Test equipment laboratory refrigerators · i.Series / Horizon family

Helmer Scientific HLR105: troubleshooting and error codes

The ServiceForge knowledge base holds 34 documented symptoms for the Helmer Scientific HLR105, with 131 ranked causes, 1 diagnostic checks with test points and expected values, and 0 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

Chamber temperature does not stabilize at setpoint caution

Temperature fluctuates or fails to reach and hold desired setpoint

Ranked causes

  1. 1. Monitor/control board is faulty (occasional)
  2. 2. Compressor starting relay is faulty (occasional)
  3. 3. Temperature monitor/controller board is faulty (occasional)
  4. 4. Condensing unit fan is not running (occasional)
  5. 5. Unit cooler fan is not running (occasional)
  6. 6. Compressor motor has seized (rare)
  7. 7. Control probe is out of calibration (occasional)
  8. 8. Control probe is faulty (occasional)
  9. 9. Refrigerant level is too low (occasional)
  10. 10. The probe bottle is empty (rare)
  11. 11. Condenser grill is dirty (common)
  12. 12. Air circulation at chamber top is not adequate (occasional)
  13. 13. Ambient air temperature around refrigerator is too high (occasional)
  14. 14. A component is faulty or internal connections are loose (rare)

14 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Chamber temperature does not stabilize at refrigerator setpoint

Temperature fluctuates or fails to reach desired setpoint and maintain it

Ranked causes

  1. 1. Temperature controller is faulty (common)
  2. 2. Condensing unit fan is not running (common)
  3. 3. Unit cooler fan is not running (common)
  4. 4. Compressor motor has seized (occasional)
  5. 5. Refrigerant level is too low (common)
  6. 6. Compressor starting relay is faulty (occasional)
  7. 7. Condenser grill is dirty (common)
  8. 8. Circulation in the chamber is not adequate (common)
  9. 9. Ambient air temperature around the refrigerator is too high (occasional)
  10. 10. A component is faulty or internal connections are loose (rare)

10 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Condenser alarm is active caution

Condenser temperature alarm is triggered or remains active

Ranked causes

  1. 1. Refrigerant level is too low (common)
  2. 2. Connections for the condenser temperature probe are loose (common)
  3. 3. Condenser temperature probe is faulty (occasional)
  4. 4. Condenser fins are dirty (common)
  5. 5. The compressor is overheating due to a lack of air flow (common)
  6. 6. Condenser probe is not calibrated (occasional)
  7. 7. The condenser alarm setpoint is too low (occasional)
  8. 8. The condenser fan motor is faulty (occasional)
  9. 9. A component is faulty or internal connections are loose (rare)

9 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Door Open alarm activates sporadically

Door alarm triggers intermittently during normal door operation

Ranked causes

  1. 1. Door is not closing completely (common)
  2. 2. Door is closing but not sealing completely (common)
  3. 3. Connections for the door switch are faulty (occasional)
  4. 4. Door switch is faulty (occasional)
  5. 5. Control board is faulty (occasional)
  6. 6. A component is faulty or internal connections are loose (rare)
  7. 7. Door Ajar Timeout is set to zero, causing the alarm to activate immediately when the door is opened (occasional)

7 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Refrigerator in alarm condition but alarm not active or audible patient safety

Alarm setpoint reached but alarm does not sound or display

Ranked causes

  1. 1. Alarm system is faulty (occasional)
  2. 2. Monitor/control board is faulty (occasional)
  3. 3. Alarm buzzer is faulty (occasional)
  4. 4. A component is faulty or internal connections are loose (rare)
  5. 5. Alarm Disable key is in OFF position (common)
  6. 6. Audible alarms are muted (common)
  7. 7. Alarm setpoint was changed (occasional)

7 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

AC Power Failure alarm active despite power connection

Power failure alarm displays even when refrigerator is connected and powered

Ranked causes

  1. 1. Outlet connection is faulty (common)
  2. 2. Power cord is faulty (common)
  3. 3. ON/OFF AC power switch is faulty (occasional)
  4. 4. ON/OFF AC power switch is OFF (common)
  5. 5. A component is faulty or internal connections are loose (rare)
  6. 6. Circuit breaker is tripped (occasional)

6 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

AC Power Failure alarm is active while refrigerator is connected to power high voltage

Power failure alarm displays even though unit is plugged in and receiving power

Ranked causes

  1. 1. Outlet connection is faulty (common)
  2. 2. Power cord is faulty (common)
  3. 3. ON/OFF AC power switch located inside the front lower panel is faulty (occasional)
  4. 4. ON/OFF AC power switch is OFF (common)
  5. 5. A component is faulty or internal connections are loose (rare)
  6. 6. Circuit breaker is tripped (occasional)

6 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Chamber temperature displayed is higher or lower than actual temperature

Monitor reading does not match actual chamber temperature

Ranked causes

  1. 1. Monitor probe is not calibrated (common)
  2. 2. Connections for the monitor probe are loose (common)
  3. 3. Monitor probe wiring is an open circuit (occasional)
  4. 4. Probe bottle is empty or solution level is too low (occasional)
  5. 5. Digital electronics are locked because of an interruption in power (rare)
  6. 6. Monitor is not calibrated (common)

6 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Door Open alarm activating sporadically

Door alarm triggers intermittently or unexpectedly

Ranked causes

  1. 1. Door is not closing completely (common)
  2. 2. Door is closing but not sealing completely (common)
  3. 3. Connections for door switch are faulty (occasional)
  4. 4. Door switch is faulty (occasional)
  5. 5. Monitor/control board is faulty (occasional)
  6. 6. A component is faulty or internal connections are loose (rare)

6 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

High Temperature alarm activates on door open, clears on close patient safety

Alarm triggers when door opens, automatically clears when door closes

Ranked causes

  1. 1. Monitor probe connections are loose (common)
  2. 2. Monitor probe is faulty (occasional)
  3. 3. Unit cooler fan continues to run while door is open (occasional)
  4. 4. Probe bottle is empty (occasional)
  5. 5. High temperature alarm setpoint is set too low (occasional)
  6. 6. A component is faulty or internal connections are loose (rare)

6 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

High Temperature alarm activates when door opens, clears after door closes

Temperature alarm false trigger occurs during door opening cycle

Ranked causes

  1. 1. Connections for the monitor probe are loose (common)
  2. 2. Monitor probe is faulty (occasional)
  3. 3. Unit cooler fan continues to run while the door is open (occasional)
  4. 4. Probe bottle is empty (occasional)
  5. 5. High temperature alarm setpoint is set too low (common)
  6. 6. A component is faulty or internal connections are loose (rare)

6 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Automatic temperature tests do not work

Temperature test function does not execute or fails to complete

Ranked causes

  1. 1. Connections for the monitor probe are loose (common)
  2. 2. Monitor probe is faulty (occasional)
  3. 3. Control board is faulty (occasional)
  4. 4. High Alarm setpoint is set significantly higher than the default value, or the Low Alarm setpoint is set significantly lower than the default value (occasional)
  5. 5. A component is faulty or internal connections are loose (rare)

5 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Refrigerator is in alarm condition but alarms are not audible

Alarm condition exists but no sound is heard from alarm system

Ranked causes

  1. 1. Alarm system is faulty (occasional)
  2. 2. Control board is faulty (occasional)
  3. 3. Alarm buzzer is faulty (common)
  4. 4. A component is faulty or internal connections are loose (rare)
  5. 5. Audible alarms are muted (common)

5 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Compressor runs continuously caution

Compressor does not cycle off during normal operation

Ranked causes

  1. 1. Refrigerator setpoint is set too low (common)
  2. 2. Control probe in unit cooler is faulty (occasional)
  3. 3. Monitor/control board is faulty (occasional)
  4. 5. Defrost timer is faulty (occasional)

5 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Drawer or basket does not slide easily

Drawer or basket movement is restricted or stiff

Ranked causes

  1. 1. Debris in drawer slides (common)
  2. 2. Drawer slides are not lubricated (common)
  3. 3. Drawer or basket is misaligned or not level (occasional)
  4. 4. Drawer slide is faulty (rare)

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Display shows 'Prob' but chamber temperature is correct

Error message displays despite proper temperature setpoint

Ranked causes

  1. 1. Monitor probe connections are loose (common)
  2. 2. Monitor probe wiring is an open circuit (common)
  3. 3. A component is faulty (rare)

3 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Door does not open easily

Door opening is restricted or stiff

Ranked causes

  1. 1. Debris in the hinges (common)
  2. 2. Hinge is faulty (occasional)
  3. 3. Lower hinge spring and/or pin may be bent or faulty (occasional)

3 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Excessive water in chamber caution

Water or condensation accumulation inside the refrigeration chamber

Ranked causes

  1. 1. Humid air is entering the chamber (common)
  2. 2. Connection between unit cooler and drain tube is loose (occasional)
  3. 3. Defrost timer bypass switch may be in ON position (occasional)

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Refrigerator meets alarm condition but appropriate alarm is not active

Alarm does not trigger when alarm condition is met

Ranked causes

  1. 1. Control board is faulty (occasional)
  2. 2. Alarm setpoint was changed (common)
  3. 3. A component is faulty or internal connections are loose (rare)

3 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Alarm is activated but temperature recorded at activation does not match alarm setpoint

Alarm triggers at temperature value that differs from programmed setpoint threshold

Ranked causes

  1. 1. The monitor settings are not calibrated (common)
  2. 2. The temperature changed slightly around the time of activation (common)

2 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

All alarms are activating sporadically

Multiple or all alarm types trigger intermittently without clear cause

Ranked causes

  1. 2. Control board is faulty (occasional)
  2. 5. Condenser alarm setpoint is too low (occasional)

6 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Excessive moisture on doors

Condensation or moisture accumulation visible on exterior or interior door surfaces

Ranked causes

  1. 1. Humid air is entering the chamber (common)
  2. 2. Relative humidity around refrigerator is too high (occasional)

2 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Alarm activated but recorded temperature does not match setpoint

Temperature reading at alarm activation differs from alarm setpoint

Ranked causes

  1. 1. Temperature changed slightly around activation time (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Alarm monitor is not responding

Monitoring system fails to respond to commands or events

Ranked causes

  1. 1. Digital electronics are locked because of an interruption in power (occasional)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Chamber temperature does not meet alarm condition but alarm is inactive

Temperature alarm setpoint does not activate when expected

Ranked causes

  1. 1. Temperature alarm setpoint was changed (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Chamber temperature meets alarm condition but appropriate alarm is not active

Alarm does not trigger when temperature reaches setpoint threshold

Ranked causes

  1. 1. Temperature alarm setpoint was changed (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Excessive moisture in evaporation tray

Abnormally high water level in internal evaporation tray

Ranked causes

  1. 1. Humidity or drainage issue (unknown)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Excessive water found in the evaporation tray inside the refrigerator

Water level in internal evaporation tray exceeds normal operating level

Ranked causes

  1. 1. Humid air is entering the chamber or drainage issue (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Excessive water in lower evaporation tray caution

Water level in lower compartment evaporation tray is abnormally high

Ranked causes

  1. 1. Humid air is entering the chamber (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Excessive water in water evaporation tray inside lower compartment

Water level in condensation tray is higher than normal

Ranked causes

  1. 1. Humid air is entering the chamber (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Monitor display is hard to read

Screen brightness is inadequate for reading display information

Ranked causes

  1. 1. Screen brightness is set too low (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

No Battery alarm is activating sporadically

Backup battery alarm triggers intermittently

Ranked causes

  1. 1. The battery voltage level on the backup batteries for the monitoring system is low (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Probe Failure is displayed on the monitor

Display shows probe failure message

Ranked causes

  1. 1. Monitor probe wiring is an open circuit (common)
First check

Measure probe resistance

Test point
Monitor probe
Expected
86 Ω to 110 Ω, 86 to 110

2 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Water leaks from bottom of refrigerator caution

Water dripping or leaking from bottom exterior of unit

Ranked causes

  1. 1. Humid air is entering the chamber (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Community

0 fixes logged by technicians through their AI, with outcomes, for this model.

ServiceForge knowledge base record. Field-unverified unless technicians confirmed it. A teaching summary of the record, not a service manual. Export 2026-10-14.