FC Load Calculations & Equipment Sizing

Question 1

What is the primary purpose of a Manual J load calculation in furnace installation?

Accepted Answer

To calculate the heating and cooling loads of a structure

Answer

To determine the correct fuel type for a furnace

Answer

To size the ductwork for a forced-air system

Answer

To establish the minimum AFUE rating required by code

Question 2

Which unit is most commonly used to express a furnace's heating output capacity in the United States?

Accepted Answer

British Thermal Units per hour (BTU/h)

Answer

Kilowatts (kW)

Answer

Therms per hour

Answer

Calories per minute

Question 3

Which of the following factors is typically included in a Manual J residential load calculation?

Accepted Answer

Window area and glazing U-value

Answer

Homeowner's personal comfort preferences

Answer

Furnace brand and model number

Answer

Local utility gas rates

Question 4

What does 'design temperature difference' (ΔT) mean in the context of heating load calculations?

Accepted Answer

The difference between indoor design temperature and outdoor design temperature

Answer

The difference between supply and return air temperatures

Answer

The temperature rise across the heat exchanger

Answer

The range between high and low thermostat setpoints

Question 5

How does increasing a ceiling's insulation R-value affect the calculated heating load?

Accepted Answer

It decreases the heating load by reducing heat loss through the ceiling

Answer

It increases the heating load due to greater thermal mass

Answer

It has no effect on heating load calculations

Answer

It increases the heating load by trapping cold air

Question 6

In Manual J calculations, which ACCA manual is used after the load is determined to properly select furnace equipment?

Accepted Answer

Manual S

Answer

Manual D

Answer

Manual N

Answer

Manual P

Question 7

What does the 99% outdoor design temperature represent in a heating load calculation?

Accepted Answer

The temperature that is equaled or exceeded only 1% of the hours in the heating season

Answer

The temperature exceeded 99% of the year

Answer

The thermostat setpoint used for 99% of residences

Answer

The maximum rated temperature for furnace operation