313D Load Calculation and Blueprints 3

Question 1

What is the primary purpose of a Manual S calculation in residential HVAC design?

Accepted Answer

Equipment selection based on Manual J loads

Answer

Manual S uses the Manual J load results to select properly sized heating and cooling equipment for the residence.

Question 2

On blueprints, what does the scale '1/4" = 1'-0"' mean?

Accepted Answer

One quarter inch on the drawing equals one foot in reality

Answer

A scale of 1/4" = 1'-0" means every quarter inch measured on the drawing represents one actual foot in the field.

Question 3

Which internal heat gain source is typically the largest contributor in a residential cooling load?

Accepted Answer

Occupants and lighting combined

Answer

Occupants (sensible and latent body heat) and lighting are typically the dominant internal heat gain sources in residences.

Question 4

What is 'infiltration' in the context of a residential load calculation?

Accepted Answer

Uncontrolled air leakage into or out of the building

Answer

Infiltration refers to uncontrolled air leakage through cracks, gaps, and openings in the building envelope.

Question 5

When reading a duct layout on blueprints, what does a rectangular box with an 'X' drawn through it typically represent?

Accepted Answer

An exhaust or return air grille

Answer

A rectangular symbol with an X through it commonly denotes a return air grille or exhaust register on HVAC plans.

(313D) Residential Air Conditioning Systems Mechanic Certification Practice Test