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88 Cards in this Set
- Front
- Back
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Schedule 40 pipe is rated for a max of what psi? |
125psi |
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Can copper used for gas be soldered? |
No. Only flared, brazed or compression. Compression must be double ferrule system |
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What coppers can be used for gas lines? |
Type K,L and G. L and G must be coated with PVC resin or extruded polyethylene |
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What kind of plastic can be used for gas? |
Polyethylene. Fused or compression |
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Polyethylene pipe must be installed with what when underground? |
Tracer wire |
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Minimum rated working pressure for a hose and hose fittings? |
350psi (2400kpa) |
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Max length of hose on a permanent installation? |
10 feet |
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If there is less then 1 3/4 clearance from finished wall and gas tight what must be installed? |
16 gauge protection plates |
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Steel bushings may reduce one or more sizes but malleable bushings must reduce? |
Two or more sizes |
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Max length of flex connector on a vented appliance and unvented appliance? |
2 feet and 6 feet |
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Why should plastic pipe underground be snaked? |
Allows for contraction and settling |
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All gas lines should to be buried at depth underground? |
15". 24" for driveways |
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Density of propane and gas? |
1.5 and 0.6 |
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Additional appliances may be installed within how many feet of the meter outlet? |
2 feet or 2 feet of secondary reg on propane line |
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Minimum pressure test requirements for low pressure gas line? |
15 psi for 15 mins. 15psi for 60 mins over 200' of pipe |
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Finish piping must be tested at? |
Working pressure for 10 mins |
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A purge on a gas line should be how far from any building or air intake? |
10' |
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How must a 4" or bigger gas line be purged? |
Using an inert gas usually carbon dioxide |
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All welded gas pipe will be tested for? |
50 psi or 1.5 times max operating pressure for 180 minutes |
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When can a dual stage regulator be used on a propane install? |
Only for temporary installs |
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Can a second stage regulator set at 11" WC be used to supply a 2 psi gas pressure? |
Yes |
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Every hose and hose fittings shall have minimum pressure rating of? |
350psi |
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A defective section of gas pipe or tubing may be repaired by a qualified gas fitter? |
False |
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A corrugated metal connector shall not exceed 2' in length when? |
Connecting a suspended appliance |
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How far is the valve from purge point? |
No more then 5 feet |
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Underground piping approved for direct burying? (No protection or coating) |
Type K copper tubing |
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Min bury depth under commercial driveway? |
24 inches |
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When installing PE plastic pipe underground is shall have what buried with it? |
Tracer wire |
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Final test preformed on a piping system? |
10 mins at working pressure |
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A branch piping outlet (future outlet) installed on main supply must be what size? |
Full size |
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When a fabricated tee is used to provide an outlet on a 3 inch gas line, it is sized? |
No larger then 50 percent of supply pipe and no smaller then 3/4 |
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Max pressure for CH4 in an industrial building? |
66psi |
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Other then a building under construction, max pressure for C3H8 in piping system? |
20psi |
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When sizing 2psi gas lines, TFD allowance must be added? |
No. Only 5psi |
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Cathodic protection is used to prevent damage to a gas line from? |
Galvanic action |
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Pressure gauge for testing a standard residential gas line should have a max pressure reading of? |
60psi |
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When should you purge a gas line? |
After every test with air and before a gas line is dismantled for repair |
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What will cause a manual re-set type of regulator to drop out? |
Closing upstream valve and opening the downstream valves |
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How many 90 degree elbows are used in war is know as 3 elbow swing joint? |
3 |
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Gas leaking from regulator vent could indicate that something on the seat is preventing it from closing? |
Yes |
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Replacing a piece of 1/2 schedule 40 piping with a piece of 1/2 schedule 80 would cause? |
Reduction in operating pressure at the appliance |
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System regulator should be tested to a maximum of what pressure? |
Working pressure |
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Underground piping is often snaked before back filling why? |
Contraction and expansion |
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A gas line from a house to detached garage would require how many gas cocks? |
3. 1 leaving house, 1 entering garage and 1 at the appliance |
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Best type of sling to lift 2" schedule 40 pipe? |
2 leg choker sling |
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Flow rate in 1" steel pipe supplying 200cfh at 7" WC and 1" pipe supplying 75cfh at 7" WC. would pressure be at first pipe more or less? |
More then |
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Fittings with left hand threads may be used on a propane gas piping where? |
On outlet of a cylinder |
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The installation of natural gas regulator fall under the B-149gas code when they are? |
Downstream of the meter and supplied as part of the appliance |
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What is included as part of the total equivalent length in high pressure gas system? |
Shut off valve at second stage regulator and fittings |
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In a 2psi gas system the max pressure drop allowed is? |
1.5psi |
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If a gas meter needs to be changed, what should be done? |
Notify the owner |
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Incomplete combustion will produce? |
CO, CO2 and H2O |
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What kind of pipe cannot be used above ground? |
Plastic PE pipe |
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Before dismantling any gas line you should? |
Shut off gas, shut off appliance power supply and purge |
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Every hose and fitting must be rated for what minimum working pressure? |
350psi |
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Copper gas line is residential must be marked with yellow bands every? |
6 feet |
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Largest component of natural gas is ? |
Methane |
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The term volatile in gas fitting trade is used in reference to? |
How easy gas mixes with air |
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Mercaptan is added to gas to? |
Increase safety in handling |
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What gas is almost never handled as a liquid by a gas fitter? |
Natural gas CH4 |
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The UEL of natural gas is? |
15 percent |
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2 gallons of propane liquid would weigh? |
10 pounds |
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Natural gas has density of? |
.60 |
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Max pressure an appliance gas control valve can be subject to? |
.5psi or 14" WC or 8 OSI |
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2psi. It's before the regulator |
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Max length of corrugated metal flex connector permitted on a vented appliance and unvented appliance? |
2 feet and 6 feet |
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Second stage regulator on propane line is set to what water column? |
11" WC but can be adjusted to supply 2 psi gas pressure |
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Max pressure drop on 2psi systems? |
1.5psi, 75 percent |
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Can an appliance under 400MBH have its gas line purged to the burner? |
Yes but the burner cannot be inside of a combustion chamber |
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Natural gas requires how much cubic feet of air to burn 1 cubic feet of gas? |
10 cubic feet |
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Propane requires how much cubic feet of air to burn 1 cubic feet of gas? |
24 cubic feet |
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What kind of wiring diagram is most widely used? |
Ladder diagram |
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What does a "relay" do? |
Opens and closes a set of electrical contacts and is activated by a coil |
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What does a "contactor" do? |
Same as relay but works with larger current rating. 20 amps or larger |
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How does low limit switch work? |
Low limit will open (turn off) if temperature drops below 40 degrees Celsius |
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Volts are? |
Pressure |
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Amps are? |
Current |
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Ohms are? |
Resistance |
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Series circuit? |
One path and most likely one load controlled by switch or series of switches |
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Parallel circuit |
More than one path with most likely having one load or path. Voltage drop across each load with be the same |
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Series parallel? |
Combination of the two, within that circuit the loads wired in parallel and switching devices in series |
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What does a rod and tube thermostat sense? |
Liquid |
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What does a bimetal thermostat sense? |
Air temperature change |
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What does a heat anticipator do? |
Designed to prevent system lag or temperature overshoot |
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Where is a diaphragm and solenoid gas valve located? |
Downstream of 100 percent shut off valve and the appliance regulator |
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A direct fired makeup air heater cannot be installed in? |
A space that doesn't have a exhaust fan |
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A stationary gas engine (generator) must have exhaust connected too? |
Separate high temp chimney or exhaust |
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Swimming pool heaters must have what kind of base? |
Non combustible |
