Rev. 0508
71
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 determine 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
2°F. The thermometer should be checked for
proper calibration. (It should read 32°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.
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 temperature, checks should be
made for the following:
1. Has the refrigerator been loaded with
warm product?
2. Is the product loaded beyond the “Safe
Load Line” markers?
3. Are the return air ducts blocked?
4. Are the entering air ducts blocked?
5. Is a dumped display causing turbulent air
flow and mixing with room air?
6. Are spotlights or other high intensity
lighting directed onto the product?
7. Are there unusual draft conditions (from
heating/air-conditioning ducts, open
doors, etc.)?
8. Is there exposure to direct sunlight?
9. Are display signs blocking or diverting
airflow?
10. Are the coils of the refrigerator iced up?
11. Is the store ambient over 75°F, 55% RH
as set forth in ASHRAE Standard 72 and
ASHRAE Standard 117?
12. Are the shelf positions, number, and size
other than recommended by Hussmann?
13. Is there an improper application or control
system?
14. Is the evaporator fan motor/blade
inoperative?
15. Is the defrost time excessive?
16. Is the defrost termination, thermostat (if
used) set too high?
17. Are the refrigerant controls incorrectly
adjusted?
18. Is the air entering the condenser above
design conditions? Are the condenser fins
clear of dirt, dust, etc.?
19. Is there a shortage of refrigerant?
20. Has the equipment been modified
to use replacements for CFC-12,
CFC-502 or other refrigerant? If so,
have the modifications been made in
accordance with the recommendations
of the equipment manufacturer? Is the
refrigerator charged with the proper
refrigerant and lubricant? Does the system
use the recommended compressor?
appendices (Cont'd)
