Turbo Air KUCTB2503 Installation & Operation Manual page 11

continue to operate to facilitate the melting of
frost on the fan surface. Other types of defrost
Electric defrost
The recommended electric defrost circuitry is
typically using a defrost heater.
During defrost cycle, compressor and fan are
stopped automatically
predetermined times.
In generally, electric defrost uses defrost timer for
preventing over heating.
There are two kinds defrost timers. Turbo air uses
bimetal method.
During the defrost cycle, if the room temperature
rises above the desired setting, defrost heater will
turn off automatically and if the room temperature
Defrost Thermostat
Bimetal Disc Type
Turbo air uses Klixon type thermostat made by
Texas Instruments Company.
This thermostat terminates defrost at 50 (10 )
and prevents the fans from running when the coil
temperature is above 40 (4.4 ). And defrost
termination/fan delay
defrost at 55 (12.8 ) after defrost is finished.
This will allow fan delay time for eliminating the
residual water and slush in the evaporator coil.
Fan delay time can be eliminated by jumping the
fan switch contacts. This will allow the fans to
start immediately after defrost termination. This
will disable the fan delay.
When the coil temperature reaches approximately
40 (1.7 ), fan delay is sends a signal to the
control circuit, and it will run fan motor. If you
wish to control fan delay time and defrost
by the timer at
thermostat terminates
schemes require that the fans on the evaporator
shut off during the defrost period.
drops lower than desired temperature,
Defrost heater will turn off.
If the defrost time finished, defrost timer will turn
on and the compressor and fans will run
continuously.
At this time, fan power is supplied later than
compressor power by fan delay thermostat. If it
does not, a partial defrost results and the residual
water and slush will re-freeze into ice during the
next cycle. Ice removal will require a manual
defrost.
termination time, adjust the position of thermostat.
If this method is used, it will result in higher
temperature.
Adjustable Type ( F25 Series )
The F25 Control terminates defrost and delays
evaporator fan operation following a defrost cycle.
The coil temperature rises during the defrost cycle
to the control cut-out setting. At this setting the
defrost cycle terminates and refrigeration starts.
The fan remains off during the initial start-up of
the refrigeration cycle. When the coil temperature
drops to the control cut-in setting, the fan is
turned on. The delayed fan operation prevents
warm moist air from being circulated into the
controlled space and danger of increased vapor
pressure and product damage is eliminated.
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