Helmer Scientific i.Series
®
Ultra-Low Freezer
Service and Maintenance Manual
360173-A/C
17
Calibrate control/primary monitor probe
1. Move contents within the freezer to gain access to the probe located in the bottom compartment against the rear wall.
2. Using a zip-tie, attach the independent thermometer to the cover surrounding the probe.
3.
Close the door and allow the chamber temperature to stabilize for a minimum of five minutes.
4. Observe and note the thermometer temperature.
♦
If the temperature variance is within ±1.0 °C of the temperature displayed, calibration is not necessary.
♦
If the temperature variance is greater than ±1.0 °C of the temperature displayed, calibrate the sensor.
5. Touch,
i.C³ APPS
,
Settings
,
Sensor Calibration
.
6. Touch minus (-) or plus (+) on the corresponding spin box to increase or decrease the value to match the measured value.
7. Remove thermometer from the sensor cover.
8. Replace freezer contents.
Ambient Temperature Probe
Verify ambient temperature sensor is reading ambient temperature correctly by comparing sensor reading to temperature read by an
independent, calibrated and traceable thermometer. If sensor is not reading correctly, change the offset value displayed on the monitor.
CAUTION
Avoid sharp edges when working inside the refrigeration compartment.
Notes
•
The ambient temperature probe is factory-calibrated and should be verified on an annual basis. Calibrate when required or
as dictated by facility standard operating procedures.
•
The ambient temperature probe is 100 Ω platinum RTD.
• Ensure the independent thermometer is not touching the condenser or any other metallic components in the area.
Calibrate ambient temperature probe
1. Remove the condenser grill to gain access to the sensor.
2. Using a zip-tie, attach the independent thermometer (with 5’ (1524mm) lead or greater) to the same point as the sensor.
3. Allow the thermometer temperature to stabilize for a minimum of three minutes.
4. Observe and note the thermometer temperature.
♦
If the temperature variance is within ±1.0 °C of the temperature displayed, calibration is not necessary.
♦
If the temperature variance is greater than ±1.0 °C of the temperature displayed, calibrate the ambient sensor.
5. Touch,
i.C³ APPS
,
Settings
,
Sensor Calibration
.
6. Touch minus (-) or plus (+) on the
Ambient
offset spin box to increase or decrease the offset value until the displayed value
matches the measured value.
Note
After saving the new temperature value, the displayed temperature may take several minutes to change to match the new
value.
7. Remove thermometer from the sensor.
8. Replace the condenser grill.
Factory-Calibrated Sensors
The low stage compressor discharge sensor, cascade heat exchanger sensor, high stage compressor discharge sensor, and high stage
condenser discharge sensor are factory-calibrated and do not require field calibration.
These sensors are difficult to reach to verify the accuracy of any calibrations.
