12
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.
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
thermostat
terminates 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
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.
Defrost Timer Setting
For Paragon’s 8145-20B type ;
Timer should be set correctly. Determine
the number of defrosts per day and the
best time of day for it to occur. Insert
pins accordingly. Set the fail-safe time to
terminate the defrost a few minutes
beyond
the
estimated
temperature
termination time. Air defrost termination
time is usually 30 to 50 minutes. The
colder the room, the longer the fail-safe
time required. Electric defrost systems
normally have a 25 to 40 minute fail-safe
time.