hussman Q1-DC Manuale Utente

33

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 °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.

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?

.  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 7 and 

ASHRAE Standard 117?

1. 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-1, 

CFC-50 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?

1.0  Hussmann Corporation provides instructions 

and recommendations for proper periodic 

cleaning. The user will be responsible for 

such cleaning, including the cleaning of low 

temperature equipment within the compartment 

and the cooling coil area(s). Cleaning practices, 

particularly with respect to proper refrigerator 

unloading and warm-up, must be in accordance 

with applicable recommendations.