One cubic foot of methane will require 15 cubic feet of air for complete combustion.

In order to secure approval to furnish and install special equipment, a subcontractor must provide the contractor with a/an

According to Manual J, the indoor design temperature for heat loss calculations is:

Resistance is the opposition to the flow of electrons in an electrical circuit and is measured in ohms. All conductors and devices exhibit some resistance to electron flow.

Permanent split capacitor (PSC)  motors are commonly used on compressors. They use a switch to drop the start winding out of the circuit.

A four branch parallel circuit has 2 amps of current in one branch and 3 amps, 6 amps, and 7 amps in the other branches. The branch with the larger load is the ________ branch.

Because different motors produce different amounts of back or counter electromotive force (BEMF / CEMF), the potential relay must be sized for the specific compressor it is to be installed on.

According to the Iinternational fuel Gas Code,  there should be _____tapered threads for size ½ and ¾?

A 120 volt circuit contains an 80 ohm resistor in series with a two resistor parallel bank having resistances of 100 ohms and 400 ohms respectively. What is the total resistance in the circuit?

ASHRAE 62 reconmends furnace filters with a MERV rating of ______which will protect the furnace from damaging particulates and provide some removal of allergens.