Exam 24: Gas and Oil Central Heating Systems

Which of the following is NOT a typical Class 2 wiring application in homes?

Class 2 circuits are ____________________ and are considered safe from fire hazard and from electric shock hazard

Do not throw selenium thermostats into the trash because the selenium is considered hazardous waste material.

Class 2 wiring ____ permitted in the same raceway, cable, compartment, outlet box, or fitting with light and power conductors, even if the Class 2 conductors have the same 600-volt insulation as the power conductors.

Hot water systems are very adaptable to zone control by using a combination of one or more circulating pumps and/or valves for the different zones. Hot water heating systems are referred to as ____________________ systems.

Most residential heating systems are packaged units in which many items are preassembled, prewired parts of the furnace or boiler. They are included in an integrated printed circuit board module, which is the "____" of the system.

In the diagram below, label the type of circuit represented by each part of the installation, choosing from among the following. You may or may not require all the types listed. Power supply wiring Class 1 wiring Class 2 wiring Class 3 wiring Communications wiring

Disconnect switches for furnaces installed in basements are required to be ____.

Because they have internal overload protection, listed Class 2 transformers are permitted to be supplied by branch circuits having overcurrent protection not exceeding ____ amperes.

Manufacturers of heating and cooling equipment provide separate openings for bringing in the Class 2 wiring and separate openings for bringing in the power supply.

Residential thermostats should be located where they will not be influenced by ____.

Thermostats are usually mounted approximately ____ in. above the finished floor.

A remote-control circuit is any electrical circuit that ____________________ through a relay or equivalent device.

Explain the purpose of interrupted duty ignition on a gas furnace.

How does the Code define a remote-control circuit?

NEC 422.12 requires that central heating equipment of any type (electric resistance, gas, oil, heat pump) must ____.

Class 2 power source voltage limitations, current limitations, and overcurrent protection requirements are found in ____.

Low-voltage wiring used for door bell and thermostat wiring in a residence is generally Class 2 wiring, which has a thermoplastic insulation with a voltage rating of not less than ____________________ volts.

Oil-fired heating systems move hot air from the furnace through hot air ducts that in turn connect to hot air registers strategically located throughout the home.

____ circuits offer alternative wiring methods regarding voltage, power limitations, wire size, derating factors, overcurrent protection, physical protection, insulation, and materials that differentiate these types of circuits from conventional wiring methods.