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Is Your Refrigerator Not Cooling? Before Calling A Refrigerator Technician Consider These Tips.

equipment for testing a commercial refrigerator image on the Due North website

If your commercial refrigerator is not cooling, there are some helpful Minus Forty troubleshooting procedures you can follow. Repairs must be performed by trained service personnel on your team. If all else fails, you can call a refrigerator technician or Minus Forty technical support.

If you plan on working on your own unit, prior to calling a refrigerator technician, consider doing a pre-service safety check. Firstly, by checking the unit for the type of refrigerant used: markings on the compressor, nameplate, and red colored process tubing will indicate whether flammable refrigerant is used. Use a combustible gas leak detector rated and certified for R290 (propane) refrigerant to perform a background check around the unit and inside the refrigerated compartment. To avoid risk of injury, do not use leak detectors with an arc or spark module to check for leaks in and around units that use flammable refrigerants. Service personnel must be trained on proper device use, and the device must be certified for use with the specific refrigerant class being serviced. If your commercial refrigerator is not cooling and flammable refrigerant is detected, immediately ventilate the room, evacuate the area, and notify the owner or customer. Recheck the area with a combustible gas leak detector and wait until the detection device reads a safe level before conducting the service.

You should use proper protective gloves, eyewear, and appropriate PPE for arms. Flammable refrigerants and compressor oils may cause frostbite and may cause chemical burns. Also ensure a dry-powder fire extinguisher rated for Class B fires is accessible on site. Technicians should be trained in the use of these fire extinguishers.

Utilize a tubing cutter, not a torch or other heated surface tools, due to flammable refrigerants when access to the sealed refrigeration system is needed.

Conduct all servicing in a well-ventilated area. Whenever possible, open a window, door, or other means to ventilate the area. Take extra care if the repair work is done in a confined space, including providing enhanced ventilation to prevent formation of flammable mixtures in the ambient air.

If your refrigerator is not cooling, before calling a refrigerator technician check the following:

  1. Thermostat or electronic controller set too warm
  2. Merchandiser loaded with excessive amount of warm product
  3. Refrigerator is not cooling due to excessive door openings
  4. Insufficient installation clearance and improper power supply
  5. Condenser coil clogged with dust and/or dirt
  6. Evaporator frosted up
  7. Fans not rotating
  8. Refrigerant leaks
  9. Compressor failure and replacement
  10. Call Minus Forty or a refrigerator technician

Thermostat or electronic controller set too warm

 This can easily happen, where the thermostat or electronic controller is set too warm. When your Minus Forty refrigerator is not cooling, the first thing you should do is thermostat adjustments, which are explained in detail in our Owner’s Manuals that can be accessed on our Manuals page.

On models equipped with electronic thermostats, press P button on the controller, SP1 flashing will follow, then use arrow UP and/or arrow DOWN to increase/decrease the desired temperature. Press and release P to store the selected temperature.

On other models, if the refrigerator is not cooling, locate the electromagnetically thermostat at the back of the unit. Using a spade screwdriver, turn the thermostat knob clockwise for cooler temperature or counterclockwise for warmer temperature.

Merchandiser loaded with excessive amount of warm product

You’re in the business of selling and this means keeping a well-stocked refrigerator or freezer merchandiser. However, if your refrigerator is not cooling, it may be overstocked or loaded with large quantities of warm product. The thermal mass of the refrigerated or frozen products helps to maintain the unit’s interior temperature.

Overloading your merchandiser units blocks interior airflow that can lead to spoiled food and equipment damage, forcing you to call a refrigerator technician. Commercial refrigeration cabinets are better able to maintain a stable temperature if they’re stocked with products (not overstocked) versus depleted. For your merchandiser units to stay happy and healthy, distribute the product evenly inside.

Refrigerator not cooling due to excessive door opening

Customers can be indecisive when it comes to buying product leading to excessive door opening. Your commercial refrigerators or freezers can easily lose their cool from this action. Minus Forty glass door merchandisers have an available option of a factory installed, proprietary SmartConnect IoT technology integrated into them. The technology provides door opening status. It’s basically a built-in food health monitor that alerts retail managers to a change in the commercial freezer or cooler temperature that could jeopardize the integrity of the food. Standard on all our locking merchandiser freezers if the temperature rises above a certain temperature point for a pre-set period, the merchandiser unit automatically locks the door preventing access to potentially contaminated food.

Insufficient installation clearance and improper power supply

The most important thing to remember during the installation process of a Minus Forty merchandiser is to make sure it is plugged into a dedicated circuit. There are other key things to keep in mind when it comes to clearance, it must be six inches away from the wall to allow for the proper air circulation through the condenser. If there is not at least six inches between the cabinet and the wall, it may cause the cabinet to overheat and increase the chance of product loss. More than one item plugged into the same outlet can cause a breaker to overload. Each breaker may be loaded with two to three outlets. You must make sure that your commercial fridges and freezers are on their own dedicated 15-amp circuit breaker. If this is not done, you drastically increase the opportunity of the unit to fail.

Condenser coil clogged with dust and/or dirt

Our commercial refrigerators and freezers are designed for minimal condenser cleaning. With the “lint free” condenser design, most dust and dirt will pass right through the condenser. To ensure the proper operation, we recommend scheduled check-ups and cleaning every three to four months. This period may be shorter or longer depending on the location in which the freezer is installed. A dirty condenser can result in a voided warranty, part failure, product loss, and higher electrical cost. The steps to clean the condenser are as follows and you can find more details in our operating manuals:

  1. Remove the front bottom grill
  2. Switch off power at freezer switch on control panel
  3. Unplug power cord from electrical receptacle
  4. Brush the dirt, dust, and paper off the condenser coil plate, all the way to the fan. Use either a vacuum or blow with a compressed air supply if available
  5. When finished with cleaning, plug power cord back into receptacle
  6. Switch power back on at switch on control panel
  7. Replace bottom grill

Evaporator frosted up

Excessive ice/frost build up adversely affects freezer performance and can be the reason why your refrigerator is not cooling. It restricts the air flow through the evaporator and reduces cooling performance. Inspect the evaporator coil through evaporator fan openings. If the front of the coil is covered with ice/frost, the freezer may have a defrost problem. No need for a refrigerator technician, you can troubleshoot this on your own by following the seven steps we have listed on page 6 in our Technical Service Bulletin.

Fans not rotating

The evaporator fan(s) control and operation are briefly summarized as:

Freezers: The evaporator fan(s) are controlled by the evaporator/defrost probe, the door switch, and the controller. The fan(s) stops when the door is open. When the evaporator probe temperature is at or above 25 °F, the controller shuts off the evaporator fan(s). When the evaporator probe temperature is below 20 °F, the evaporator fan(s) are running continuously.

Refrigerators: The evaporator fans are controlled by the door switch and the controller and run continuously except when the door(s) is open. The evaporator/defrost probe has no impact on the evaporator fan operation. Some refrigerator models in specialty pharmaceutical applications have the evaporator fan(s) programmed to be off during compressor off time.

Freezers and Refrigerators: When the controller calls for fans to run, the “Fan” symbol is lit on the controller display. To obtain evaporator probe reading, press and release U on the controller, then “Pr2” will be flashing followed by the evaporator probe actual temperature.

The condenser fan(s) are controlled by the controller and are wired in parallel with the compressor to run concurrently. Condenser fan(s) and compressor do not run during the 6-minute start-up delay when the controller is repowered (“StArt dELAy” message scrolled on the controller). If the controller calls for the compressor (“Comp” symbol lit on the controller) and the compressor runs but the condenser fan(s) does not run, then follow the steps on page eight (8) here.

If both the compressor and the condenser fan(s) do not run when the controller calls for, then check the controller cooling relay and the compressor external relay (refer to Section C above). More on condenser fan diagnosis on page eight (8).

Refrigerant leaks

Our upright freezers have a static/standing pressure of around 95PSIG and refrigerators have around 80PSIG at 80°F ambient temperature. This can be useful information for determining whether a unit has a refrigerant leak. If the unit is unplugged for about 24hrs or longer and if the standing pressure on either low or high side is less than 80PSIG (freezers) or 60PSIG (refrigerators), it is highly likely the unit has a refrigerant leak. There are various measures for leak identification in commercial refrigeration units:

  • Finding leaks with electronic leak detector
  • Finding leaks with soap test
  • Finding leaks with pressure decay test
  • Looking for indirect signs of escaped refrigerant

For more information on the steps involved in these measures, so that you can conduct them yourself instead of calling a refrigerator technician, read our Technical Services Bulletin for maintenance suggestions on the various unit models.

 Compressor failure and replacement

 Compressors typically fail because something in the commercial refrigeration system changes externally, which adversely affects the compressor’s performance. The most common root causes of compressor failures are dirty or blocked condenser, condenser fan motor failure, evaporator fan motor failure, power supply out of range, refrigerant leak, faulty compressor electricals (capacitors, relays, and overload protector), incorrect installation, etc. Here is a complete listing of the nine items to check for compressor diagnosis.

It is essential to establish the type of compressor failure that has occurred and whether a compressor burnout has occurred. If the compressor failure resulted from some form of an electrical failure, the compressor has undergone a burnout condition of some degree of magnitude. It is essential to determine the type and extent of the burnout before the new compressor is installed. If there was a mechanical failure that would cause a no pump condition (any situation where the motor starts and runs okay but little or no refrigerant is pumped), the system cleanup procedure can be bypassed. See our twelve detailed steps for compressor replacement.

Call Minus Forty

Nobody understands Minus Forty merchandiser freezers and coolers better than we do. So before calling the refrigerator technician, call us if your commercial refrigerator is not cooling.

First check if there is a label on the merchandiser stating what service phone number to call. If there is no such label, the next step is to call the owner of the merchandiser. You may also call our service and warranty representative at tel. 1.800.800.5706, ext. 128; or 905.702.1441, ext. 128.

You can also always try the following troubleshooting tips, like:

  • Power cord unplugged or loose
  • Faulty receptacle
  • Circuit breaker tripped, or blown fuse, or open supply circuit
  • Improper supply voltage to the merchandiser due to other electrical equipment on the same electrical circuit
  • Merchandiser power switch turned off
  • Merchandiser in the 6-minute start-up delay mode Wait until delay expires.
  • Thermostat or electronic controller set for too warm temperature.

Minus Forty products are built to last, with greater up-time and lower maintenance requirements and costs. We back up our products with a one-year warranty on parts and labour and a five-year warranty on the compressor parts. Along with a nationwide network of preferred service technicians, our customer support is available 24/7 with a friendly team that can troubleshoot and quickly resolve any issue that may arise.



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