Thermo Products OD6FX072DV5R 사용자 설명서

 

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8.  As a final step in the installation, the appliance must be adjusted to deliver a temperature rise within 

the range of 50° to 80°F. Adjust the blower motor speed to obtain a temperature rise within the 
acceptable range. The required blower speed will depend on the airflow resistance of a supply and 
return air duct systems. 

 

 
The RETURN AIR DUCT SYSTEM should equal the warm air duct system in airflow capabilities.  
 
NOTE: When a return register is located in the same room as the furnace, the register must be at least 20 
feet away from the furnace. 
 
SIZING THE DUCT WORK FOR A COMBINATION HEATING AND COOLING SYSTEM: 
Two formulas must be used in determining the CFM requirements of a combustion heating and cooling 
system. 
 
1. HEATING CFM: 
    HEAT OUTPUT OF FURNACE (BTUH) 
    1.1 X TR (TEMPERATURE RISE, °F) = HEATING(CFM) 
 
    EXAMPLES: 
    A. 110,000 BTUH OUTPUT 
         1.1 X 85°F TR = 1176 CFM FOR HEATING 
 
    B. 110,000 BTUH OUTPUT 
         1.1 X 70°F TR = 1429 CFM FOR HEATING 
 
2. COOLING CFM: 400 CFM X COOLING TONNAGE (12,000 BTUH PER TON)=AIRFLOW FOR 
COOLING(CFM) 

    EXAMPLES: 

A.  400 CFM X  3 TON (12,000 BTUH) = 1,200 CFM FOR COOLING 
 

 

 

 

1TON 

 

B.  400 CFM X 2.5 TON (12,000 BTUH) = 1,000 CFM FOR COOLING 
 

 

 

 

1 TON 

 
IMPORTANT: SIZE THE DUCT SYSTEM FOR THE LARGER OF THE TWO AIRFLOW 
REQUIREMENTS.