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66 Cards in this Set
- Front
- Back
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What kind of manual shut off valve would be used on a gas pipe larger than 1 inch in diameter? |
A lubo- seal |
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When could diversity of load be applied to gas installation? |
When winter appliances (heating boilers )and summer appliances (swimming pool heaters) are connected to the same |
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What would not be classified as an operating control? |
Flow switch |
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What control would be classified as a combustion safety controls? |
Thermocouple |
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Where is the induced draft fan located on a mid efficient appliance? |
On the outlet of the heat exchangers(appliance vent outlet) |
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What is the function of a low pressure limit control installed on a valve train? |
If the gas apply pressure drops too low gas valve will close |
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What can be determined by a sail switch? |
Airflow I plugged air filter Frosted AC coil |
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What device would be used to prove the operation of an induced draft fan? |
Pressure switch |
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What is the maximum setting of a high temperature limit control on a forced air furnace? |
250°F |
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What can be the operating control for a forced air furnace? |
The thermostat |
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What classification of power supply would a 115/24VAC -40VA step down transformer be included in? |
Class two power supply |
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What control could have the summer /winter switch incorporated into it? |
The combination fan /limit control |
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How many temperature set points are found on a combination fan /limit control? |
Three |
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When the high temperature limit control is wired into the 120 V AC circuit of a conventional furnace what device does a control? |
The power to the primary coil of the step down transformer |
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What should be the first thing check when troubleshooting the 24 V control system on a conventional forced air furnace? |
The thermostat |
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Which device would not be found in 120 V control system? |
A transformer |
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What is the function of a heating thermostat? |
A device that closes its contacts on temperature drop |
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What device is energized when a cooling thermostat closes it’s contacts? |
A relay coil |
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What is the importance of terminal RC in a thermostat or appliance circuitboard? |
This is the power input for the cooling circuit |
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How is an adjustable heat anticipator setpoint determined? |
It is set to the amperage draw of the heating circuit |
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What is the flow of electrons called? |
Electric current |
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What does the term capacitive reactance describe? |
The opposition voltage change |
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What is inductance? |
The opposition to change in current in a circuit |
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What is impedance? |
The total opposition to current flow in an AC circuit |
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How is inductive reactance measured? |
Ohms |
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How is impedance determined |
Impedance must be calculated, and cannot be measured |
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What would a digital metre display if the resistance of a broken coil were taken? |
The metre with display one decimal or OL |
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What would a digital meter display if the voltage were taken across an energized open switch? |
The meter would display the voltage supplied to the switch |
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What is the liquefaction (expansion) ratio for propane? |
270 |
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What is the specific gravity (relative density )of propane liquid? |
.51 |
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What is the specific gravity (relative density) of natural gas? |
.6 |
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What is the specific gravity (relative density) of propane gas? |
1.5 |
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How many cubic feet of propane gas can be produced from 1 gallon of propane liquid? |
43.6 |
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What is the calorific value of natural gas? |
1000 btus/ft3 |
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What is the calorific value of propane gas ? |
2500 btu/ft3 |
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What is the calorific value of 1 gallon of propane liquid? |
109,560 btus |
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What is ignition temperature of natural gas? |
1200 degrees Fahrenheit |
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What is the flame speed of propane gas? |
32 in./s |
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What is the range of flammability of natural gas |
5 to 15% |
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What is the range of flammability of propane gas? |
2.3- 9.5% |
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How many cubic feet of air is required to burn one cubic foot of propane gas? |
24 |
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How many cubic feet of air are required to burn one cubic foot of natural gas? |
10 |
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What is a product of poor combustion? |
Carbon monoxide |
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Which are products of good combustion? |
CO2 H2O And N2 |
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What is soot ? |
C deposits |
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What is theoretical combustion air? |
Primary and secondary air only |
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What is uncontrolled combustion? |
An explosion |
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Why does the air supply duct installed as per gas code Not keep the building at neutral pressure.? |
The duct was not sized to replace the air exhausted by fans |
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What causes the venting action in the vent the category 1 fan assist appliance? |
Convection |
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Why is a chimney serving a single drafted appliance, one size larger than the vent connector? |
To allow for the increase in internal surface area |
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What is the minimum clearance from a protected combustible wall for a single wall vent connector? |
2 inches |
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What is the minimum gauge of aluminum vent connector? |
22 B&SG |
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What is the vent connecter rise? |
The distance from the appliance outlet to the centre of the tee into the vent Connection |
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What size of ventilated metal thimble is required for a single wall vent connecter less than 6 feet in length passing through combustible wall? |
4 inch larger than the diameter of the vent connecter |
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What method would be used to determine if there was a draft in the vent system? |
A smoke or match test |
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If I shut off valve installed on outlet of a pump what else is required? |
A pressure bypass |
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What is the minimum size of concealed gas piping? |
Half inch diameter |
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What is the advantage of using high-pressure gas installations over low pressure, gas installations? |
It allows smaller pipe sizes. Make an installation cheaper. |
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When installing a system regulator on a two psi gas line, where must a vent terminate? |
The vent may have a ball check leak limiter installed in the vent outlet that discharges into a ventilated |
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What fixed element controls the amount of gas a pilot will burn? |
The office in the pilot burner |
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A thermocouple has an open circuit voltage of 15 mV and a close circuit voltage of 10 mV what needs to be done with the system? |
The power unit must be replaced |
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What should be done to correct too much pressure drop in a gas line? |
Increase the size |
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Permanent propane, installations require how many stages of pressure reduction? |
Two-stage |
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Name the part of the regulator that determines the maximum capacity of gas, that can pass through the regulator |
The restricting element |
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How is the maximum firing rate of the appliance determine? |
Using the value listed under the input, heading on the rating plate |
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What is the approximate flame speed of natural gas? |
26 in./s |
