27
d) Complete start-up procedures should include checking through a defrost to make certain of its
adequate frequency and length without substantially exceeding the actual needs. This should include
checking the electrical or refrigerant circuits to make sure that defrosts are correctly programmed for
all the refrigerators connected to each refrigeration system.
e) Recording instruments should be used to check performance.
Appendix C. - Field Recommendations
Recommendations for fi eld 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 (see Appendix A). In practical use, the precise determination of return air temperature is
extremely diffi cult. 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 fi rst 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 fi rst 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 fi rst 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 fl ow 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 airfl ow?
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?
12. Appendices (Cont'd)
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