A display shows the temperature now. A record shows what happened at 3 a.m., over the weekend and during last month’s power cut. That record protects your stock, answers an inspector’s questions and warns you of faults before they stop the room. This guide explains what a cold room temperature monitoring system should measure, where the probes go, how to set alarms and what to do when one fires.
Why a record beats a display
- Product safety. Bacteria multiply fastest between +5 °C and +60 °C. A chiller room can drift above +5 °C for hours at night and read normal again by morning. Only a record shows it.
- Inspections. Municipality and SFDA inspectors commonly ask food businesses for temperature records.
- Insurance and disputes. After a breakdown, a time-stamped record shows when the temperature left the range and for how long. That supports a spoilage claim. It also shows whether a delivery arrived warm or warmed up in your room.
- Early fault detection. Slower recovery after door openings, higher peaks after defrost and a rising night-time average often show on the trend before a failure.
What to monitor
- Air temperature. It reacts fast and shows every door opening and defrost.
- Product temperature. A probe inside a product simulant shows what the food itself reaches. It moves far more slowly than the air.
- Door openings. A door switch records how often and how long the door stands open. Our guide to cold room doors covers door-open alarms.
- Defrost. The start and end of each defrost explain the regular peaks on the air curve.
- Power. A power cut at night stops the room without warning. The monitor needs its own battery to report it.
Rooms for fresh produce often add a humidity probe.
Where to place the probes
The controller’s own probe usually sits in the air returning to the evaporator. A monitoring probe should be separate, so a faulty control probe cannot hide its own error. Place it where the room is warmest in normal use:
- At upper shelf height, because warm air rises.
- Toward the door side, but not in the doorway.
- Out of the cold air stream leaving the evaporator, which reads too cold.
- Away from lights, heaters and the wall surface.
A small walk-in needs one independent probe. Large rooms need several, spread between the door, the far corner and different heights. Pharmaceutical stores and large warehouses commonly run a temperature mapping study first to find the warm and cold spots.
Three levels of cold room temperature monitoring
| Feature | Controller display | Data logger | Connected system |
|---|---|---|---|
| What it does | Shows the current temperature and sounds a local alarm | Records the temperature at fixed intervals for download | Sends readings to an online platform and alerts phones |
| Record | Only if staff write readings on a sheet | Automatic and time-stamped | Automatic, stored off site, reports on demand |
| Warning when nobody is on site | No | No | Yes, by SMS, app or email |
| Weak point | Depends on people and keeps no history | Shows the problem after it happened | Needs backup power, a data connection and a person assigned to respond |
| Typical fit | Small rooms with low stock value | Restaurants, shops and small stores | High stock value, pharmaceuticals, several sites, unattended nights |
Controllers from Carel, Dixell and Danfoss, brands listed among Cooliva’s technology partners, typically include high and low temperature alarms. Many models can also pass their readings to a monitoring system.
Alarm thresholds and delays
An alarm that sounds every day gets ignored. Set it to fire only when something is wrong. General chilled food is typically held at 0 to +4 °C, frozen food at -18 °C or colder and many pharmaceuticals at +2 to +8 °C. Confirm the limits for your products with your supplier and the applicable SFDA requirements. See our guide to cold room temperature by product.
- Threshold. Set the high alarm at the upper limit your product allows, not at the setpoint. Add a low alarm for chilled goods that must not freeze, such as leafy vegetables.
- Delay. Door openings and defrosts raise the air temperature for a short time. Watch two or three normal defrosts on the record and note how long the air takes to come back. Set the delay slightly longer.
- Defrost. Freezer rooms defrost with electric heaters or hot gas several times a day, so short regular peaks are normal. Many controllers can hold the alarm back during and after defrost. See our guide to cold room evaporators.
- Two stages. Use an early warning for a small drift that lasts and a critical alarm for a large rise.
- People. Send alerts to at least two phones and test the alarm at each maintenance visit.
Calibration
Have thermometers and data loggers calibrated once a year and keep the certificates with your records. For a quick check between visits, stir the probe in a glass of crushed ice and water. It should read 0 °C or close to it. If it does not, have the probe adjusted or replaced and note the finding.
How long to keep records
No single period fits every business. A sound rule is to keep records at least as long as the shelf life of the products that passed through the room, plus a margin. Check the period that SFDA requirements, your quality system and your customer contracts set for your activity.
What to do when an alarm fires
- Read the trend. How high is the temperature and how long has it been rising?
- Check the simple causes. Is the door open? Is the power on? Is the room in defrost? Are the evaporator fans turning? Is the outdoor unit running?
- Protect the cold. Keep the door shut and stop loading warm product.
- Measure the product. Use a calibrated hand probe. Warm air for a short time does not always mean warm product.
- Call your service technician if the cause is not a door or a defrost.
- Move the stock to another room or a refrigerated truck if the temperature keeps rising. Start with fresh meat, fish and dairy.
- Decide and document. Judge the product under your food safety procedure. Log the time, the highest temperature, the cause and the action taken.
Regular cold room maintenance prevents many alarms.
Frequently asked questions
Is the controller display enough for an inspection?
The display shows one value at one moment. Inspectors commonly want to see records over time. A log sheet filled in by hand at fixed times each day is the minimum. An automatic data logger is more reliable. Check what applies to your activity with your municipality and the SFDA requirements.
Why does my freezer show a temperature peak several times a day?
That is defrost. Heaters or hot gas melt the frost on the evaporator and the air near the probe warms for a short time. The product stays frozen. Call a technician when the peaks grow higher or longer or when they appear outside defrost times.
Does a connected system still work during a power cut?
Only if it was planned for one. The sensors and the gateway need battery backup and the data link must not depend on a router that loses power. A mobile data connection is the usual answer. A good system also alerts you when a sensor stops reporting.
Can I add monitoring to an existing cold room?
Yes. Stand-alone data loggers and wireless sensors need no change to the refrigeration system. Seal any cable hole made through a panel.
Monitoring in a Cooliva project
Cooliva is based in Riyadh and designs, supplies and installs cold rooms and freezer rooms for food, pharmaceutical and logistics businesses across Saudi Arabia. Ask us to include the controller, alarm and recording options in your offer, matched to the stock you need to protect. Monitoring can also be added to a running room as part of a refurbishment and upgrade. Tell us what you store and who should receive alerts through the contact page or call +966 59 799 1000.
