Evaporator Fans Running During Defrost

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Beverage Air Freezer Temperature is Rising – CFG36-1

A client stated that the his freezer temperature was rising however upon arrival we found the unit operating normally with a temperature of -3*F. I increased the temperature control setting to see if I could get the unit to cycle off. The current setting was at # 6. Turned the temperature control knob to setting to # 3 when unit cycled off. Reset temp control back to # 6 to turn refrigeration system back on. Checked the compressor amps and checked system pressures. Pressures, amperage and condenser fan motor all functioning properly. Tested defrost by manually turning defrost timer to the defrost position. Once initiated I checked heater amperage with meter and found they were pulling 4.8 amps which was normal. I noticed the evaporator fans were still running during the defrost cycle. Disconnected the power to the unit and tested the fan switch on the defrost timer. Found the switch was closed when it should have been open during defrost position. Replaced the defrost time clock with new and tested defrost with a 5 minute duration. This time evaporator fans were off, as they should. Allowed the defrost cycle to complete the five minute cycle. Once completed the heaters turned off and the refrigeration system started. Finally, the evaporator fans cycled back on, once the evaporator temperature dropped.  I set the current time on time clock and set defrost to occur 4 times per day with a 45 minute duration. Informed client that, during defrost, the inside fan motors should not be operating as they will blow heat from the heating elements into the refrigerated area. This will not only increase the box temperature but increase the product temperature as well. Put unit back together and watched temperature for 10 minutes. The freezer temperature was 5*F before leaving. Also, recommended the client replace the torn door gaskets.

For a better understanding on the defrost timer operation, check out this YouTube Video: How a Freezer Defrost Timer Operates