Unit 8 Test 17 March Flashcards
a device for adjusting gas line pressure to the pressure specified by the appliance manufacturer?
Gas pressure regulator
an electric switch that prevents a gas valve from opening unless a pilot light is present?
Pilot safety control
an electrical device that controls the flow of gas and can be millivolt, 24 VAC, or 115 VAC depending on the application?
Solenoid valve
plugs threaded into gas burner manifolds that meter precise amounts of gas to individual burners?
Orifice
an adjustable opening on a gas burner that meters the amount of air to mix with the gas to produce a proper flame?
Primary shutter
a small opening in the gas burner that diverts a small amount of gas to assist in lighting all burners in a gas furnace?
Pilot runner (crossover igniter)
a junction of two dissimilar metals that produces a voltage when heated and serves as a safety device on gas furnaces?
Thermocouple
an electrical device in a furnace blower assembly that energizes the blower from a remote location?
Fan relay
an air collection chamber?
Bonnet
an electrically operated valve that controls the flow of gas?
Gas valve
to remodel, repair, or replace. In air conditioning and refrigeration it generally means replacing older system components with a new component.
Retrofit
Any device which utilizes fuel or other forms of energy to produce light, heat, power, refrigeration or air conditioning.
Appliance
An air chamber with a minimum dimension of one foot in the direction of air flow to form part of an air distribution system.
plenum
Installed where headroom is not a problem.
When installed in closets, these furnaces require special clearances from combustible materials.
upflow
Installed where basement or crawl space cannot be used, and supply ducts are located under the floor.
When this furnace is installed on a combustible floor, it requires a special supply adaptor.
counterflow
Installed in crawl space or attic where headroom is limited.
Heat exchangers in these furnaces are subjected to greater stress than heat exchangers in other furnace types.
horizontal
Installed outside and ducted into the house.
Because these units are usually a combination of furnace and air conditioner, they are called ‘package units’, and they are usually vented by a draft induced instead of gravity.
outdoor
Installed in basements where head room is limited.
These furnaces have horizontal type heat exchangers.
lowboy
Installed in basements, and frequently used to convert furnaces from coal to gas operation.
Supply ducts in this type of furnace should be installed as nearly vertical as possible and all ducts should be as large as possible because these have no blowers.
gravity
A short vertical section of a gas pipe designed to trap dirt, moisture, and debris before gas enters an appliance.
drip leg
An ignition system that creates a direct spark to ignite the main burner without using a pilot flame.
direct spark igniter
A silicon carbide or silicon nitride element that heats up and glows to ignite gas burners.
hot surface igniter
A gas valve with multiple shut-off mechanisms to prevent gas flow in case of failure.
redundant valve
A metal component that transfers heat from combustion gases to air or water without allowing them to mix.
heat exchanger
A device that adds moisture to the air in a heating system to improve indoor comfort and prevent dryness.
humidifier
A pipe or distribution chamber that evenly supplies gas or refrigerant to multiple burners or circuits.
manifold
A temperature-activated switch that controls the operation of a blower fan in a heating system.
fan switch
A safety control that shuts off the burner or equipment if temperatures exceed safe operating limits.
limit switch
A small popping sound caused by sudden flame extinction due to loss of fuel, air, or pressure changes.
extinction pop
A dangerous condition where the flame burns back into the burner or gas-air mixture chamber due to improper combustion.
flashback
