Many of our customers use their temperature loggers to monitor vaccine fridges. Vaccine fridges have better temperature control than many other types of fridges and the results tend to be very predictable. Then there are the sudden changes which causes the readings to be in a new range.
What causes a sudden shift in temperature logger readings?
The most common cause cause of a shift in temperature logger readings is restocking. This causes the airflow in the fridge to change and if you overstock a fridge you can create warmer and cooler locations within the fridge.
Using stock or changing the position of stock will cause a change but this tends to happen over time and so is normally seen as a slow change over time, not a sudden shift.
Moving the logger is a likely cause. People tend to put the logger in the same location each time so we don’t hear about it as a problem. What we do hear about is when it accidentally falls into a strange location and gives more extreme readings.
What causes short term changes?
Short term (minutes or hours) spikes are more often due to use or environmental issues. User issues such as leaving the door open, or opening the door frequently will cause the temperature to rise. Power failures will cause the power to fail.
One obscure issue we came across was where the fridge was in a sub-zero degree location and the temperature went below 0° inside the fridge. That’s to be expected because fridges only cool, they can’t heat. The solution was to heat the room and ensure it never dropped below 0°C.
What if it has shifted out of range?
If it is hovering near the 2° or 8° mark then
– check the location and if it was NOT where vaccines are stored, then retest the fridge with the logger in a better location
– consider if there was an environmental issue that could have caused the change
– finally, contact your service company and discuss it with them. There may be a simple adjustment that will help bring the temperature back in range.