Appendix C. - Field Recommendations - Refrigerated - Emerson Liebert GXT3 User Manual

Rev. 0909

Appendix C. - Field Recommendations - Refrigerated

Recommendations for field evaluating the
performance of retail food refrigerators and hot
cases
1.0 The most consistent indicator of display
refrigerator performance is temperature of the air
entering the product zone (Refrigerated see
Diagram 1, Appendix A). In practical use, the
precise determination of return air temperature
is extremely difficult. Readings of return air
temperatures will be variable and results will be
inconsistent. The product temperature alone is
not an indicator of refrigerator performance.
nOTe: public Health will use the temperature of the product in
determining if the refrigerator will be allowed to display
potentially hazardous food. For the purpose of this
evaluation, product temperature above the FDA Food
Code 1993 temperature for potentially hazardous food
will be the first indication that an evaluation should
be performed. It is expected that all refrigerators will
keep food at the FDA Food Code 1993 temperature for
potentially hazardous food.
1.1 The following recommendations are made
for the purpose of arriving at easily taken and
understood data which, coupled with other
observations, may be used to determined
whether a display refrigerator is working as
intended:
a) INSTRUMENT - A stainless steel stem-type
thermometer is recommended and it should
have a dial a minimum of 1 inch internal
diameter. A test thermometer scaled only
in Celsius or dually scaled in Celsius and
Fahrenheit shall be accurate to 1°C (1.8°F).
Temperature measuring devices that are
scaled only in Fahrenheit shall be accurate
to °F. The thermometer should be checked
for proper calibration. (It should read 3°F
when the stem is immersed in an ice water
bath).
b) LOCATION - The probe or sensing element
of the thermometer should be located in
the airstream where the air first enters the
display or storage area, and not more than 1
inch away from the surface and in the center
of the discharge opening.
c) READING - It should first be determined
that the refrigerator is refrigerating and has
operated at least one hour since the end
of the last defrost period. The thermometer
reading should be made only after it has
been allowed to stabilize, i.e., maintain a
constant reading.
Appendices (Cont'd)
d) OTHER OBSERVATIONS - Other
observations should be made which may
indicate operating problems, such as
unsatisfactory product, feel/appearance.
e) CONCLUSIONS - In the absence of any
apparent undesirable conditions, the
refrigerator should be judged to be operating
properly. If it is determined that such
condition is undesirable, i.e., the product is
above proper temperat ure, checks should be
made for the following:
1. Has the refrigerator been loaded with
. Is the product loaded beyond the "Safe
3. Are the return air ducts blocked?
4. Are the entering air ducts blocked?
5. Is a dumped display causing turbulent air
6. Are spotlights or other high intensity
7. Are there unusual draft conditions (from
8. Is there exposure to direct sunlight?
9. Are display signs blocking or diverting
10. Are the coils of the refrigerator iced up?
11. Is the store ambient over 75°F, 55% RH
1. Are the shelf positions, number, and size
13. Is there an improper application or control
14. Is the evaporator fan motor/blade
15. Is the defrost time excessive?
16. Is the defrost termination, thermostat (if
17. Are the refrigerant controls incorrectly
18. Is the air entering the condenser above
19. Is there a shortage of refrigerant?
9
warm product?
Load Line" markers?
flow and mixing with room air?
lighting directed onto the product?
heating/air-conditioning ducts, open
doors, etc.)?
airflow?
as set forth in ASHRAE Standard 7 and
ASHRAE Standard 117?
other than recommended by Hussmann?
system?
inoperative?
used) set too high?
adjusted?
design conditions? Are the condenser fins
clear of dirt, dust, etc.?