FREEZER REPAIR EXPERTS
Repair, Sales & Installation, Maintenance in Katy, TX
Air Mobile A/C & Heating Refrigeration provides commercial freezer repair services, sales, and installation, service. Our refrigeration business is based on old-fashioned hard work and traditional refrigeration principles. We aspire to deliver a diversified range of products and services custom tailored to meet your requirements. We constantly explore new technologies to provide the most effective solutions for our customers.
Freezer Troubleshooting for Repair
The commercial freezer is an essential part of many cafeterias, restaurants, and convenience stores. It is also a large energy user but is rarely considered until problems emerge. Commercial freezer problems include failure to maintain pressure and compressor failure, both of which can result in expensive losses to the products stored in the freezer. These problems, as well as unnecessarily high energy use, can be avoided by observing equipment and taking corrective action.
Freezer Repair Diagnostic Protocol
Commercial Freezer Malfunction 1:
"Power is on, but control board does not display"
- Phase loss or fuse blown
- Power phase open or transformer shorted
- Control board failure
- Check wiring for breaks and replace fuse
- Check transformer output voltage (12V)
- Replace cold storage room control board
Commercial Freezer Malfunction 2:
"Control board displays, but compressor does not run"
- Compressor relay tripped
- Hi-Lo pressure safety switch shut down
- Defective contactor or coil
- Cold room temperature is lower than operation set-point
- Internal thermal overload tripped
- Compressor malfunction
- Determine reason and take corrective action
- Determine type and cause of shutdown and correct it before re-setting safety switch
- Repair or replace
- Reset operation temperature setpoint
- Wait until compressor cools down for reset
- Check compressor motor winding
Commercial Freezer Malfunction 3:
"High discharge pressure"
- Dirty condenser coil
- Fan not running
- System overcharged with refrigerant
- Clean commercial freezer condenser coil
- Check fan motor and it's electrical circuit
- Reclaim excess refrigerant
Commercial Freezer Malfunction 4:
"Low discharge pressure"
- Insufficient refrigerant in system
- Low suction pressure
- Check for leaks; repair and add charge
- See corrective steps for low suction pressure
Commercial Freezer Malfunction 5:
"High suction pressure"
- Excessive load
- Expansion valve overfeeding
- Reduce load
- Regulate superheat
Commercial Freezer Malfunction 6:
"Low suction pressure"
- Lack of refrigerant
- Plugged suction filter
- Evaporator dirty or iced
- Fan not operating
- Expansion valve underfeeding
- Check for leaks, repair, and add charge
- Replace suction filter
- Clean and defrost
- Check fan motor and circuit control
- Regulate superheat
Commercial Freezer Malfunction 7:
"Large difference between actual cold storage room temperature and setpoint on control panel"
- Incorrect room temperature
- Sensor placement, wire too long
- Sensor contact open
- Reposition sensing point of temperature sensor
- Enlarge wire section
- Reconnect sensor
Commercial Freezer Malfunction 8:
"Heavy frost builds up on evaporator fins"
- Too much time between defrost cycles or incompleted defrosts
- Manual defrost and adjust defrost cycle
Commercial Freezer Malfunction 9:
"High temperature alarm"
- Overload and Door open excessively
- Bad refrigeration performance
- Heavy frost buildup on evaporator
- Reduce load and door opening
- See corrective steps for discharge and suction pressure malfunctions
- Manual defrost and defrost cycle
Commercial Freezer Malfunction 10:
"Coil not clearing of frost during defrost cycle"
- Heater malfunction
- Not enough defrost cycles per day
- Check heater operation
- Adjust defrost control
Commercial Freezer Malfunction 11:
"Ice accumulating in drain pan"
- Defective heater
- Drain line plugged
- Check heater; replace if necessary
- Clean drain line
Commercial Freezer Malfunction 12:
"Display screen flashes, unit emits humming noise"
- Observe alarm indicator
- See alarm for remedy
Commercial Freezer Evaporators
Moisture from the air freezes onto the evaporator coils (the cooling coils in the freezer) and forms an insulating barrier to heat transfer. Airflow also decreases as the passages narrow due to ice buildup. Each evaporator has a defrost cycle to melt frost/ice that has built up on the evaporator coils. Water from the melted ice is drained from the freezer . . . ideally.
It’s not unusual, however, to find evaporators in a state of poor maintenance. For many evaporator units, the ice isn’t melted, or the water isn’t properly drained, resulting in a block of ice taking over the evaporator. When the coil freezes, heat transfer is greatly reduced resulting in the compressor working harder and longer. It works harder because the suction pressure drops making the compressor work at a higher differential pressure, thus requiring more power. It works longer because heat transfer is reduced. When ice buildup is excessive, the compressor will run all the time and the freezer temperature setpoint will not be maintained.
As the ice melts, the water has to drain out of the freezer. This doesn’t always occur. Trapped water that freezes can do significant structural damage to a freezer; especially older ones where cracks allow water to seep in, then freeze and expand. Stalactites and stalagmites of ice appearing in your freezer are reason for swift action to avoid costly damage.
Commercial Freezer Condensers
The condenser coil of the refrigeration system removes heat from the system. It’s not unusual to find condensers located in enclosed spaces or spaces with inadequate air flow to remove heat from the space. The temperature around the compressor rises resulting in higher head pressure for the compressor, which again increases compressor power.
To effectively remove heat, the condenser should be placed in a well-ventilated area where the temperature is controlled to allow heat to be removed easily. Enclosed spaces will require openings for cooling air intake and exhaust. In many cases, a fan will be required to move enough air through the space. If the condenser heat is never needed, it should be exhausted directly outside if possible.
In cases where it may be used for space heating — such as for a nearby dry storage room — controls may be installed to direct the flow indoors for heating, and outdoors when heating is not required.
Condenser coils should also be checked regularly for cleanliness. Dust and debris will act like ice buildup on an evaporator coil. This will insulate the heat transfer surface and reduce airflow, which will make the compressor run harder and longer. In extreme cases, compressors may fail.
Commercial Freezer Refrigerated Space & Shell
Although the space itself doesn’t have any mechanical parts or equipment, it shouldn’t be ignored. The shell of the cooler or freezer should be inspected regularly for leaks and loose insulation or panels. Leaks and other voids in the shell can cause excess moisture to accumulate, potentially causing even bigger problems. The door is also a key component of the cooler. Doors must be sealed properly to eliminate air infiltration which increases the cooling load and may cause moisture buildup within the space and on the evaporator. Frost buildup on the door itself is a common occurrence when the door heater fails and has a tendency to either freeze the door shut or keep it from closing. Proper care should also be taken when placing items inside the space. If the space is overcrowded with items, or items are placed in front of the evaporator fans, the circulation of air is greatly reduced along with the performance of the refrigeration system.
We hope the above diagnostic information helps you with any simple quick fixes that would help avoid trip charges and costly repairs. If however, you are not able to solve your Commercial freezer problems, please call 24 Hour Refrigeration. We have over 35 years of experience and thousands of happy customers. In most cases we can respond to any type of service call the same day. We are available 24/7 so please call now.
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