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VIII. EXPECTED THAW PERFORMANCE/OPERATIONAL TROUBLESHOOTING
VIII. a - INTRODUCTION:
Even thaw performance is a function of many factors,
especially those involving product types and loading.
As a result, actual thaw times will vary as even similar
sized loads of the same product will exhibit some
differences in their thawing characteristics.
VIII. b -
TEST PARAMETERS:
To provide a general performance baseline, Traulsen
performed some controlled testing in our lab which
may provide the operator with an approximate idea on
what to expect from their Even-Thaw unit. Full load
batches of frozen product were used as follows:
ONE SECTION MODELS
336 lbs. of chicken, distributed between 14 tray levels.
Each level consisted of 24 lbs. of product loaded into
two pans (four 6 lb. pkgs. of frozen product total per
level/two 6 lb. pkgs. per tray).
TWO SECTION MODELS
672 lbs. of chicken, distributed between 28 tray levels.
Each level consisted of 24 lbs. of product loaded into
two pans (four 6 lb. pkgs. of frozen product total per
level/two 6 lb. pkgs. per tray).
VIII. c - TEST RESULTS
Under these actual load parameters, the one-section
model generally required approximately 19-22 hours
in order to completely thaw the entire load. The two-
section model required approximately 24-26 hours to
completely thaw the entire load.
VIII. d - RESULTS AS A FUNCTION OF PRODUCT MIX:
The above thaw times were based upon a mixed load
of different chicken products typically found in many
establishments. It is important to note that initially, all
tests performed were based on a mixed load of
product. This consisted of approximately 1/4 nuggets,
1/4 strips, 1/4 to 1/3 breasts. This MIXED batch thawed
in the times listed above. In actual operation, thaw
batches consisting of a single type of product, or other
ratios of different products may require more time for
thawing. Both this and larger size loads can both
contribute to longer thaw times.
VIII. e - INCOMPLETE THAWING:
In operation, incomplete thawing (i.e. bags of product
in which not every piece was completely thawed) has
been found to usually be the result of those pkgs.
respective pan level having had restricted airflow due
to overloading (from stacked pkgs. or irregular shaped
packages that blocks air from getting to the pkgs.
closest to the cabinet interior side wall or rear).
Allowing for proper air-flow around each pkgs. of
frozen product should eliminate this situation from
occurring.
VIII. f - EQUIPMENT ISSUES:
If improper loading has been eliminated as a possible
cause for extended thaw cycle times, there are
several system checks which can be done to diagnose
the Traulsen Even-Thaw unit.
First, the amp draw should be checked early in the
thaw cycle. Shortly after loading the unit with frozen
product, the electronic control LED, “G”, should be
illuminated as the cabinet temp will probably be in the
30 to 34 degree F range as per the control read-out.
At this time, full heat should be on. This is a 1300 watt
heater, 115 vac, is about 11.3 amps. Add 4 blowers at
1.1 amps and a few amps for the controls and the total
amp draw should be approximately 16 to 16.5 amps.
When the cabinet temperature reaches 36°F, the LED
“G” will pulse indicating the heat is now being
applied at a 50% level. At 37°F, the LED “G” will be
turned off indicating thaw heat is off. This cycle will
repeat until the cabinet temperature stabilizes between
37-41°F. When the cabinet temperature exceeds 41°F,
the LED “H” illuminates indicating that the cabinet has
switched to refrigeration cycle. The cabinet will now
cycle between 37-41°F in order to maintain cabinet
temperature.
Also, be certain that the thaw switch has not been
turned OFF. This is located behind the louvers and
has a protective guard around it. This switch can turn
OFF 2 of the 3 mullion blowers and reduce airflow
which reduces thaw capability. In addition, the blower
wattage actually adds heat to the unit and helps
augment the units thawing capability.
VIII. g - OTHER CAUSES OF EXTENDED THAW TIMES:
Some frozen products are often stored in large,
irregularly shaped packages. If used, these should
always be located along the outside wall with the
largest packages being placed closest to, but not
directly against, the wall. It is IMPERATIVE that such
large packages not be placed up against the center
mullion air ducts. This could result in blocked airflow.
REDUCED AIR MOVEMENT EQUATES TO LONGER
THAWING TIMES.
Care should also be taken to avoid pushing other pkgs.
of frozen product up against the mullion sheet metal
ducts. Airflow could be blocked resulting in a similar
extended thaw time situation.
Another scenario to avoid is for packages to be placed
inadvertently up against the outside walls. They will
also block air flow down the sides of the unit. This is
especially an issue with the right side wall
because when the unit returns to normal refrigerated
operation mode, the cold air flows from the upper right
ceiling evaporator outlet, down the wall, and then
mixes into the cabinet, distributed by all the mullion
blowers. If the right wall is blocked, and especially if
blocked near the top right of the cabinet, the cold