The "E4" Mafia Lingo
Closed
The position of an electrical switch that allows electricity to through
After use, oxygen/acetylene tanks and hoses should be?
Shut off and have the hoses bled then wrapped nicely around the carrying case.
A technician diagnoses a fuel oil furnace and finds that the burner operates for around 45 seconds that shuts down. She concludes that
Cad-cell is dirty or faulty
What is a hot surface igniter made from?
Silicon Carbide
Define 1 BTU
Amount of energy required to change one pound of water one degree F
Continuity
An electrical term indicating that the wire or component tested is broken or more accurately has an open circuit
The term capillary action means to?
Draw solder/brazing material into a joint as it is being heated.
Your servicing a unit and a home that requires LP gas to be used for the furnace. You find that the flame in the furnace is burning too large and the flame is sometimes rolling out and tripping out the roll out switch. What is the possible problem?
The unit was never converted from Natural Gas to LP
The heat exchangers found in many modern furnaces are:
Serpentine
The first law of thermodynamics states that energy can be created or destroyed. (true or false)
False
Venturi
A reduction in the size of a passage that gases are passing through causing the gases to speed up
When brazing a sealed system, first recover the refrigerant, then?
open the system to the atmosphere.
You are servicing a 90% furnace and the customer claims that the unit is firing but the home never warms up. You find that they are correct and the cabinet high limit is tripping after about 5 minutes of runtime. What could be wrong?
plugged air filter or broken fan motor
The gas burners found in most modern furnaces are:
In-shot
What is changed or added to a gas valve when converting from natural gas to propane? (Name 4 things)
Spring, orifice, low pressure switch, conversion sticker
Pilot Dropout
The amount of time it takes for the pilot safety to shut off all gas supply to the burners when the pilot light is extinguished
DAILY DOUBLE
Brazing should never be attempted when the system is what?
under pressure.
What is the primary visual difference between an 80% and 90% efficiency furnace?
PVC vs Metal Flue pipe
a thermopile produces what?
mV
What are the conditions for human comfort. (Name 4)
Temperature, Humidity, Noise, Air Flow
Downflow
A furnace design that moves air from the top of the furnace to the bottom. Used in buildings with no basement
Acetylene pressure should never exceed what?
15 PSIG
On a direct hot surface ignition system the igniter is not glowing but the main gas valve is energized during a trial ignition. What is the correct test to perform
Check for voltage at the igniter, check for resistance
A flame rectification circuit produces
2-5 uA
Heat always travels is what direction?
Hot to cold