12 Plumbing Flashcards
1
Q
What should builders consult before starting a plumbing project?
A
Local plumbing codes
Codes protect health and outline necessary permits, materials, and inspection stages.
1
Q
What is stack venting?
A
A method of venting where plumbing fixtures are clustered around a central stack.
2
Q
What are the two main types of pipes in a plumbing system?
A
Supply pipes and drainage, waste, and venting (DWV) pipes
Supply pipes carry potable water, while DWV pipes carry wastewater and gases.
2
Q
What happens to fixtures far from the stack vent?
A
They do not retain water in their traps.
3
Q
What is the purpose of drainage, waste, and venting (DWV) pipes?
A
To carry wastewater, effluvia, and sewer gases away from the fixtures
DWV pipes must slope downward for proper waste flow.
3
Q
How many bathroom fixtures can be vented off a 3-in. stack vent?
A
Three fixtures (lavatory, tub, and toilet) can be vented without additional branch vents.
4
Q
What is the function of a drain trap in plumbing?
A
To keep sewage gases from rising into living spaces
Drain traps remain filled with water after a fixture empties.
4
Q
What should be avoided when stack venting?
A
Placing a toilet above other fixtures on the stack.
5
Q
What must be done to ensure a service pipe does not freeze?
A
It must run below the frost line
The service pipe typically enters a building through the foundation.
5
Q
What is the maximum allowable distance from stack-vented fixtures to the soil stack based on?
A
The size of the pipe serving a particular fixture.
6
Q
What diameter is a common main supply pipe in plumbing?
A
3/4 inch
This pipe splits into cold-water trunk lines and hot-water trunk lines.
6
Q
What is the fixture/appliance drain/trap size for a toilet?
A
3 in. or 4 in. drain size with a 2 in. vent size.
7
Q
What materials have traditionally been used for supply pipes before the 1950s?
A
Galvanized steel
Steel pipes corrode, leading to a switch to rigid copper piping.
7
Q
What is the vent size for a bathtub/shower?
A
11⁄2 in.
8
Q
What is PEX in plumbing?
A
Cross-linked polyethylene flexible piping
PEX is gaining popularity due to its flexibility and ease of installation.
8
Q
What is the required vent size for a kitchen sink?
A
11⁄2 in.
9
Q
What is the minimum slope required for drainpipes?
A
At least 1/4 inch per foot
This slope ensures that waste can fall freely.
9
Q
What is a dry branch vent?
A
A vent that never carries water.
10
Q
What is the role of vent pipes in a DWV system?
A
To admit air equal to that displaced by falling water
Vents prevent sewage gases from entering living spaces.
10
Q
What is the minimum angle for a vent takeoff from the toilet drain?
A
45°.
11
Q
What is the minimum size for main stacks and drains in a DWV system?
A
3 inches
Branch vents and drains are usually 1.5 inches or 2 inches.
11
Q
What is the minimum upward pitch required for the horizontal section of the vent?
A
1⁄4 in. per ft.
12
Q
What is needed if you want to add new fixtures or move existing ones?
A
You’ll need a permit
This is necessary because you will be changing pipes.
12
Q
What is a common vent?
A
A vent appropriate for fixtures that are side by side or back to back.
13
What height should lavatory rims typically be set at?
32 inches to 34 inches above the finish floor
## Footnote
Adjustments may be made for taller users.
13
What is a loop vent?
A vent commonly installed beneath an island counter.
14
What is the required clearance around toilets according to plumbing codes?
At least 15 inches on both sides and 24 inches in front
## Footnote
Toilets must be placed in a space at least 30 inches wide.
14
What is the purpose of an air-admittance valve (AAV)?
To eliminate the need for conventional branch vents for fixtures too far from a wall.
15
What is the function of a main shutoff valve in a plumbing system?
To control water flow from the service pipe
## Footnote
It is typically located shortly after the service pipe enters a building.
15
How do air-admittance valves function?
They allow air in when a vacuum is created and seal when the vacuum is equalized.
16
True or False: DWV pipes can be made from any number of materials.
True
## Footnote
Older houses may have drain and vent pipes made from cast iron, galvanized steel, copper, or plastic.
16
What is the minimum height for vent stacks above the roof?
6 in. above the upslope side.
17
What is a common issue with galvanized steel pipes?
Corrosion constricts flow
## Footnote
This led to the popularity of rigid copper piping.
17
What is the minimum horizontal distance for a vent stack from a parapet wall?
12 in.
18
Fill in the blank: The _____ pipe delivers water to a house.
service
## Footnote
The service pipe is crucial for connecting to municipal water or wells.
18
What are the three scenarios for renovation plumbing?
* Cutting into a stack to add a branch drain * Building out from the end of the main drain * Cutting into the main drain in midrun and adding fittings for incoming branch drains.
19
What is the minimum clearance required in front of a sink according to codes?
18 in.
## Footnote
24 in. is preferred for better access.
19
What is the minimum downward slope required for drainpipes?
1⁄4 in. per ft.
20
What is the typical height for lavatory drains above the floor?
18 in.
## Footnote
Drains should be centered under the lavatory.
20
What fittings should be used for making a 90° bend on horizontal runs?
A long-sweep ell or a combo.
21
What is the standard width range for most bathtubs?
30 in. to 32 in.
## Footnote
Standard length is typically 5 ft. to 6 ft.
21
Where are cleanouts required?
* Where a building main joins a lead pipe from a city sewer line or septic tank * At the base of soil stacks * At each horizontal change of direction of 45° or more.
22
What is the recommended height for the shower arm above the floor?
72 in. to 78 in.
## Footnote
This height accommodates taller users.
22
What is the horizontal support spacing for copper water supply pipes?
6 ft.
23
What is the typical height for kitchen sink drain exits above the finished floor?
15 in.
## Footnote
This height accommodates garbage disposals.
23
What is the vertical support spacing for CPVC water supply pipes?
10 ft. and midstory guide.
24
How far should the toilet drain be centered from the finished wall?
12 in.
## Footnote
Allow at least 15 in. of clearance on both sides.
24
What is a double combo fitting used for?
To connect two toilets back to back.
25
What is the ideal spacing for supply pipe holes under a lavatory?
4 in. on center
## Footnote
Supply pipes should be centered under the lavatory.
25
What should be done before cutting into existing drains?
Run clear water through the drains.
26
What is the typical height at which kitchen sink faucet holes are spaced?
8 in. on center
## Footnote
Align supply pipes with their centerline.
26
What type of fitting is installed when splicing a branch drain to a cast-iron stack?
A no-hub fitting.
27
What should be done if a joist interferes with the drain path?
Cut through the joist and install doubled headers
## Footnote
This redistributes the load.
27
What should be done to prevent vent gases from entering the home?
Vent stacks must terminate at least 3 ft. above any part of a skylight or window that can be opened.
28
What is the outer diameter of a 3-in. drain pipe?
31⁄2 in.
## Footnote
It requires at least 61⁄2 in. height when running between enclosed joists.
28
What is the recommended practice when ordering plumbing supplies?
Order 20% more pipe than needed and extra common fittings.
29
What is the recommended height for mixing valves above a tub spout?
12 in.
## Footnote
Individual valve stems are typically set 6 in. above the spout.
29
What is the minimum height plumbing vents must terminate above an openable window?
3 ft. above or 10 ft. horizontal distance
## Footnote
This ensures vent gases do not enter the home.
30
What type of paper is recommended for drawing plumber’s isometric sketches?
Plumber’s isometric paper
## Footnote
It helps to visualize pipe runs in three dimensions.
30
What type of fitting is used to connect a branch drain to a stack in a cast-iron system?
No-hub fitting
## Footnote
This fitting is used with no-hub couplings for secure connections.
31
What is the best tool for making a clean, square cut on copper pipe?
Pipe cutters
## Footnote
Wheeled tubing cutters are recommended for this task.
31
What is the minimum length for a cast-iron stack?
10 ft. minimum
32
What should be used to clean metal burrs after cutting copper pipe?
Reaming tool
## Footnote
A round wire brush can also be used for polishing.
32
What must be installed at the end of an extension when building out from a cleanout?
A new cleanout
33
What is the purpose of nonasbestos flame shields?
To protect wood framing when soldering joints
## Footnote
It is important to have a fire extinguisher nearby.
33
What should you do before cutting into existing drains?
Support both sides of the section to be cut
34
What is the typical height for tub faucet handles above the spout?
6 in.
## Footnote
This is customary for mixing valves.
34
What is the required slope for drain extensions?
1/4 in. per ft.
35
What is a common height for supply stub-outs in kitchens?
18 in.
## Footnote
This height is flexible due to the use of braided stainless-steel supply lines.
35
What type of coupling is used to connect to a cast-iron main drain?
No-hub coupling
36
What type of wrench is useful for gripping polished pipe without marring it?
Strap wrench
## Footnote
It is not essential but can be helpful.
36
What is the diameter of the closet bend for a toilet?
4 by 3 inches
37
What should you do before starting plumbing work?
Get a work permit and a copy of current plumbing codes
## Footnote
Following codes is essential for safety.
37
What is the recommended opening size for a bathtub installation?
12 in. by 12 in.
38
What is the purpose of adjustable wrenches?
To grip nuts without marring chrome nuts and faucet trim
## Footnote
Different sizes are needed for various tasks.
38
Fill in the blank: The center of the toilet drain should be ______ from a finish wall.
12 in.
39
What is the maximum sizes for holes and notches in joists?
Refer to guidelines on p. 341
## Footnote
Proper drilling and notching help maintain structural integrity.
39
What is the maximum diameter for holes drilled in bearing-wall studs?
40% of the width
40
What type of torch can solder fittings required for copper pipes?
Propylene or propane torches
## Footnote
Propylene is hotter and does the job faster.
40
True or False: Notches are allowed in the middle third of a joist span.
False
41
What should you obtain before starting plumbing work?
A work permit and a copy of current plumbing codes
## Footnote
Plumbing codes are essential for safety and compliance.
41
What should be used to protect pipes or electrical cables less than 1 1/4 in. from a stud edge?
Steel nail plates or shoes
42
What type of shot should you get before starting plumbing work?
A tetanus shot
## Footnote
This is important for protection against infections.
42
What type of brace should be added to support tub lips on three sides?
Ledgers
43
What type of protective eyewear should be worn during plumbing tasks?
Protective eyewear
## Footnote
This is necessary when using power tools, chiseling, soldering, and striking with hammers.
43
What is the maximum notch depth allowed for joists?
1/6 of joist depth
44
What should you wear when handling drainpipe?
Heavy gloves and disposable plastic gloves when working with solvent-based cements or soldering
## Footnote
Protects against chemicals and injuries.
44
What is the purpose of a transition coupling?
To tie new plastic branch drains to cast-iron no-hub couplings
45
What type of respirator is recommended when soldering or working around existing soil pipes?
A respirator with P100 filters
## Footnote
This provides standard protection against harmful fumes.
45
What is the minimum distance for drilled holes from the edge of studs?
5/8 in.
46
What should you do before cutting into finish surfaces?
Shut off the electrical power to nearby outlets and test with a voltage tester
## Footnote
Ensures safety by preventing electrical shock.
46
What type of fittings are used for connecting branch drains and vents in plastic DWV systems?
Plastic fittings
47
What is recommended for ventilation when joining pipes?
Ensure good ventilation
## Footnote
Heated solder and solvent-based cements give off noxious fumes.
47
What is the procedure to follow when tying into the main drain in midrun?
Flush the drain and support both sides of the section you'll cut into
48
What should be used as a flame shield when soldering joints near wood framing?
A nonasbestos flame shield
## Footnote
Prevents igniting the wood framing.
48
What is the maximum notch width allowed for nonbearing-wall studs?
40% of the width
49
What should you do if you smell gas while working?
Stop working, clear everyone from the house, and call the local gas utility
## Footnote
Gas leaks can lead to explosions.
49
What should be done if the neoprene sleeve inside a no-hub coupling won't slide on easily?
Soap the inside of the sleeve to reduce friction
50
What type of pipe is primarily used for residential installations?
Rigid copper water pipe
## Footnote
It is strong and approved by most codes.
50
What is the minimum hole diameter for drilled holes in nonbearing studs?
40% of the stud width
51
What is the simplest type of fitting used to join two straight lengths of pipe?
A coupling
## Footnote
Couplings are essential for connecting pipes.
51
What type of adapter is used when adding a tub, lav, or sink to a threaded cleanout opening?
Plastic MIP adapter
52
What fitting is used to connect pipes of different sizes?
A reducing coupling
## Footnote
This allows for size transitions in piping.
52
What is the purpose of using blocking between joists when installing a toilet?
To stiffen the floor and better support the toilet bowl
53
What is a common directional fitting for changing pipe direction?
A 90° elbow
## Footnote
Also known as a 90 or an ell.
53
What type of tool is used to cut cast iron drain pipes?
Snap cutter
54
What type of valve is most commonly used as a shutoff valve?
Gate valve
## Footnote
Lever-handled ball valves are also gaining popularity.
54
What is the ideal distance to maintain between the toilet drain center and the finished wall?
12 in.
55
What is the most commonly used type of rigid copper supply pipe?
Type M rigid copper
## Footnote
Type L and Type K are also used for specific applications.
55
What type of joint is created by using a no-hub coupling with a neoprene sleeve?
Flexible joint
56
What should you do to prepare the ends of rigid copper pipe before soldering?
Ream the inside to remove burrs and polish the ends with plumber's sand cloth
## Footnote
This ensures a good solder joint.
56
What do you need to do if the flange is below the finish floor?
Stack plastic flange extenders
57
What should be applied to the pipe and fitting before soldering?
Flux
## Footnote
It helps create a strong bond when soldering.
57
What should be done to ensure that the DWV pipe runs are supported along their length?
Support drains at least every 4 ft.
58
What should you do if you need to disconnect a soldered fitting?
Apply heat until the solder melts and gently tap the fitting off
## Footnote
This allows for easy removal without damaging the pipe.
58
What is the minimum support requirement for pipes?
Be rigidly supported every 4 ft. and at each horizontal branch connection.
59
What type of tubing is commonly used for short runs to dishwashers and ice makers?
Flexible copper tubing
## Footnote
It is easier to bend and fit into tight spaces.
59
How should pipes be supported?
Support pipes with rigid plastic pipe hangers or plastic-pipe strap.
60
What type of connection is made with compression fittings?
A ferrule of soft metal is compressed between matched nuts
## Footnote
This creates a watertight seal.
60
What is the recommended length for pipe stub-outs for lavs and sinks?
Stub-outs should stick out into living spaces 6 in. or so.
61
What is the purpose of a tubing bender?
To shape tubing without crimping it.
## Footnote
A tubing bender helps maintain the integrity of flexible copper tubing.
61
What is the purpose of a sanitary tee in branch drains?
All branch drains end in a sanitary tee, where the horizontal leg receives the trap arm from the fixture.
62
What are the two common types of fittings for connecting flexible copper tubing?
* Compression fittings
* Flared fittings
62
What is the typical size of the largest vent pipe in a vent run?
Often the 2-in. or 3-in. pipe.
63
What is a compression fitting?
A fitting that uses a ferrule of soft metal compressed between matched nuts.
63
How far above the floor should vent stacks be supported?
Support vent stacks in midstory with clamps or straps.
64
What should you do if you need to disconnect a compression fitting?
Replace the ferrule when disconnecting fittings.
64
What is the minimum height for horizontal runs of branch vents?
At least 42 in. above the floor, or 6 in. above the flood rim of the highest fixture.
65
What is a compression repair coupling used for?
To create a watertight seal without soldering on split pipes.
65
What is the procedure for testing the DWV system?
Fill DWV pipes with water after capping the stub-out for each fixture drain.
66
Why are braided stainless-steel supply lines preferred over flexible copper tubing?
They are strong, aesthetically pleasing, and easily connected and disconnected.
66
What is a common test plug used for testing DWV systems?
A glue-on cap that fits inside a DWV pipe stub.
67
What is PEX?
A flexible tubing system used for plumbing and heating.
67
What is a double dynamiter used for in testing the DWV system?
To block the combo fitting at the base of the main drain.
68
When did PEX become popular in North America?
In the late 1990s.
68
What type of test can be used if finish ceilings are in place?
An air-pressure test.
69
What are the advantages of PEX?
* Quick installation
* Fewer leaks
* Safe (no toxic components)
* Can withstand high temperatures
* Quiet operation
* Easier repair
* Cost-competitive
69
What is the purpose of dielectric unions?
They insulate and prevent electrical conductivity between different types of pipes.
70
What is a home-run manifold system in PEX installations?
A system where a single trunk line feeds multiple fixtures through manifolds.
70
What is the minimum distance that hot and cold water supply pipes should be kept apart?
At least 6 in.
71
What temperature can PEX withstand?
Up to 180°F at 100 psi.
71
What is the code requirement for shutoff valves?
Shutoff valves are required for every fixture riser.
72
How does PEX minimize air hammer?
It expands slightly, reducing pressure drops.
72
How should supply systems be tested before drywall installation?
Solder caps onto fixture stub-outs and turn on the water.
73
What are the disadvantages of PEX?
* Requires proprietary connectors
* Breaks down under UV light
* Melts when exposed to open flame
* Degrades with some oils or solvents
73
What should be done to the sink before mounting it on the pedestal?
Preattach the sink’s hardware.
74
What are the three types of PEX fittings?
* Clamp-ring fittings
* Push-fit fittings
* Compression fittings
74
What should be done to ensure the pedestal sink is level?
Shim the pedestal base as needed.
75
What is a clamp-ring fitting?
A fitting where a steel ring compresses the tubing onto a connector.
75
What is the correct installation order for a pedestal sink?
Level the pedestal, set the sink, mark lag screw holes, predrill, secure sink, attach drainpipes.
76
What is a push-fit fitting?
A fitting that uses stainless-steel teeth to secure the tubing.
76
What should be done before disconnecting supply pipes?
Shut off the valves that control them.
77
What is the consequence of connecting copper sections to galvanized pipe without a dielectric union?
Electrolysis will cause accelerated corrosion.
77
What tool is used to loosen water-supply nuts?
A basin wrench.
78
What is CPVC?
A plastic pipe material suitable for hot and cold water lines.
78
What should be done to prevent sewer gases when disconnecting a fixture?
Place a plastic bag over the drainpipe stub.
79
How do you join CPVC pipes?
Cut square, clean ends, apply solvent cement, and insert into fittings.
79
What is the first step in removing a toilet?
Shut off the water by shutting the chrome fixture stop.
80
What are the most common materials for DWV lines?
* ABS plastic
* PVC plastic
* Cast iron
80
What should be done if the drain assembly is hidden?
Cut through it to access the connections.
81
What are the advantages of plastic pipe for DWV?
* Strong
* Corrosion resistant
* Easy to cut and assemble
* Lightweight
81
What is the purpose of water-hammer arrestors?
To prevent vibration and banging in pipes when solenoid valves stop water flow abruptly.
82
What is a heat-recovery drain (HRD)?
A drain that captures heat from wastewater to preheat clean water.
82
What should you do before moving a standard tub?
Disconnect all pipes and potentially cut into the finish surfaces to expose the tub lip
## Footnote
The tub lip is often nailed to studs.
83
How does an HRD function?
Uses a heat exchanger to transfer heat from hot wastewater to cold incoming water.
83
How are lavatory basins supported?
By pedestals, cabinet counters, legs, wall-mounted brackets, or a combination of these.
84
What is the benefit of using an HRD with a tankless water heater?
It reduces energy costs by minimizing the need for stored hot water.
84
What is a common reason for preassembling hardware before mounting a sink?
It makes connections easier when the fixture is upside down.
85
What is the benefit of HRD technology in water heating?
It is most energy-efficient if its preheated water feeds a tankless, on-demand water heater.
85
What should be applied to the sink lip before installation?
A bead of silicone caulk.
86
What happens to preheated water in HRD technology during a shower?
There is no need to store the preheated water in a tank.
86
What type of sinks are particularly popular due to storage space?
Counter-mounted lavs or sinks.
87
What should not be used on PVC pipe?
ABS cement.
87
How should a sink be leveled during installation?
Level the sink front to back and side to side.
88
Why is using the wrong cement on pipes a code violation?
It can lead to weak joints and leaks.
88
What type of valve is typically attached to each supply pipe stub-out?
A shutoff valve, typically an angle stop with a compression fitting.
89
What is one characteristic of cast iron pipes?
They are relatively corrosion resistant.
89
What is a common flaw to check for in toilets?
A foot that is not flat, a deformed horn, or bowl and tank surfaces that don’t mate correctly.
90
What is a drawback of working with cast iron?
It is heavy and requires skill to cut and support.
90
What is the purpose of the wax ring during toilet installation?
To create a seal between the toilet bowl and the closet flange.
91
How much more do professionally installed cast-iron systems cost compared to plastic-pipe installations?
40% to 50% more.
91
What type of bolts should be used to avoid corrosion in toilet installation?
Stainless-steel or brass bolts and nuts.
92
What is a unique feature of copper DWV pipe?
It is lightweight and durable.
92
True or False: You should rock the toilet bowl while setting it to ensure the wax ring compresses evenly.
False.
93
What is a disadvantage of copper DWV pipe compared to plastic?
It costs two to three times as much and is less corrosion resistant.
93
What is the maximum size of the drain required for a bidet?
1 1/4 inches.
94
What tool should be used to cut ABS or PVC pipe?
A plastic-pipe saw.
94
What should be done before the final installation of a bathtub?
Preassemble the tub’s drain and overflow assembly and test-fit it.
95
What is the purpose of dry-fitting pipes before cementing?
To determine the exact direction and depth of fitting.
95
What is the recommended thickness for a mortar bed when installing lightweight steel and fiberglass tubs?
1 inch to 2 inches.
96
What should you do before applying cement to pipes?
Clean off burrs and wipe off any grit.
96
Fill in the blank: When installing a toilet, you should connect the _______ to the top of the tank.
supply riser.
97
What does applying plastic-pipe primer do?
It prepares the pipe and fitting for cement.
97
What is a common assembly for double sinks or lavatories?
End-Outlet Continuous Waste.
98
What is one-coat, no-primer plastic-pipe cement?
A new product that is promising but unproven.
98
What should be done to toilet-supply connections?
Attach a 3/8-in. chrome tubing or a flexible braided stainless-steel supply line.
99
How can you identify old light iron cast iron?
It has a higher, tinny tone when lightly struck.
99
What is the purpose of using plumber’s putty in sink installations?
To create a seal between metal and porcelain joints.
100
What should you do to support cast iron pipes before cutting?
Support the pipe on both sides of the intended cut.
100
What should be done if there is leaking between the tank and the bowl after toilet installation?
Tighten the nuts.
101
What are no-hub couplings used for?
To join cast-iron pipe and no-hub fittings.
101
What is the function of the overflow plate inside the tub?
It screws to a mounting flange in the overflow ell.
102
What is a key feature of branch vents in plumbing?
They must rise to a height of at least 42 inches above the floor.
102
What is necessary for a proper installation of a bidet?
Hot and cold-water connections.
103
What is the maximum distance a trap arm can be from a vent for a 2-inch diameter trap arm?
5 ft.
103
What type of caulk should be used for self-rimming sinks?
Clear silicone caulk.
104
What is back venting also known as?
Continuous venting.
104
What should be checked before trimming closet bolts after toilet installation?
Ensure there are no leaks.
105
What is the difference between a soil stack and a vent stack?
A soil stack carries wastes; a vent stack admits air and never carries water.
105
What type of fittings are used to connect the drainpipe to a sink or lav?
Slip-nut couplings.
106
What is a wet vent?
A vent stack that occasionally drains fixtures above it.
106
What is used to seal the metal-to-enamel joint in tub installations?
Plumber's putty
## Footnote
Plumber's putty is commonly used to create a watertight seal in plumbing applications.
107
What is the requirement for wet vents regarding soil wastes?
Wet vents must never carry soil wastes.
107
What is the purpose of the overflow plate in a tub?
Screws to a mounting flange in the overflow ell
## Footnote
The overflow plate prevents water from overflowing the tub.
108
What is crucial about the angle at which a branch vent departs from a drainpipe?
It may go straight up or at a 45° angle but must not exit from the side.
108
What is the last drain connection made in tub installations?
P-trap
## Footnote
The P-trap connects to the tub tailpiece and aligns with the branch drain.
109
What is the maximum temperature setting for a pressure-balancing valve to prevent scalding?
120°F
## Footnote
This temperature is typical for safety in plumbing.
110
Which valve is also referred to as an antiscald valve?
Pressure-balancing valve
## Footnote
This valve mixes hot and cold water to maintain a safe temperature.
111
What is required by code if the drain assembly will be inaccessible?
Glued-together drain joint
## Footnote
This prevents leaks in inaccessible areas.
112
What should be done before removing an old gas-fired water heater?
Turn off the gas
## Footnote
The stopcock must be perpendicular to the gas line.
113
What is the purpose of the TPR valve in a water heater?
To release excess pressure
## Footnote
TPR stands for Temperature and Pressure Relief valve.
114
What must be done to the discharge pipe from the TPR valve?
It must slope downward and terminate 6 in. above the floor
## Footnote
This ensures safe discharge of hot water.
115
What type of water heater does not have a storage tank?
Tankless water heater
## Footnote
Also known as on-demand or instant water heaters.
116
What is the key benefit of tankless water heaters?
They provide endless hot water
## Footnote
Properly sized units can supply hot water continuously.
117
What is the typical input requirement for a tankless heater serving a one-bath home?
140,000-Btu
## Footnote
This is a general guideline for sizing tankless heaters.
118
True or False: Tankless water heaters require less energy than traditional tank heaters.
True
## Footnote
They only consume energy when hot water is needed.
119
What should be done with the bonding jumper wires during installation?
Reclamp them for proper grounding
## Footnote
This ensures safety for the electrical system.
120
Fill in the blank: Tankless water heaters are generally more _______ and more _______ to install than traditional tank heaters.
complicated; expensive
## Footnote
Their installation requires expertise in multiple trades.
121
What is important to check before installing a tankless water heater?
Existing pipe sizes and connections
## Footnote
Most tankless units require 3/4-in. water pipes.
122
What type of venting do many tankless units use?
Concentric direct-vent pipe
## Footnote
This design allows for fresh air intake and exhaust in one pipe.
123
What should be done to ensure safe installation of a new water heater?
Follow the manufacturer's installation instructions
## Footnote
This is crucial for safety and warranty compliance.
124
What is a common issue with gas-fired water heaters that plumbers check?
Condition of vent pipes
## Footnote
Blockages can lead to dangerous situations, including carbon monoxide leaks.
125
What is the purpose of using flexible stainless-steel lines in water heater installations?
To allow easy disconnection for future repairs
## Footnote
Flexible lines simplify maintenance.
126
What should be done with threaded pipe fittings to ensure a positive seal?
Coated with pipe compound or wrapped with Teflon tape
## Footnote
This prevents leaks at the joints.
127
What is the first step in replacing an old tank-style water heater?
Turn off electrical power and shut off the water supply to the tank.
128
What tool should be used to ensure that the power is off before removing a water heater?
Voltage tester
129
What are the five essential requirements for installing a tankless water heater?
* A route for a vent pipe and an opening to the exterior
* Tie-ins to 3⁄4-in. water pipes
* An electrical outlet for the unit’s power cord
* A gas line if the unit is gas fired
* A sturdy place to wall-mount the unit
130
What is the benefit of using flexible PEX tubing for water-supply pipes?
Easier to route in a renovation
131
Before mounting the tankless unit, what should be tested?
Adequate clearance distances and room to make connections.
132
What should be applied to the threaded stubs on the underside of the unit’s housing?
Pipe dope and Teflon tape
133
What type of valve should be attached to the hot-water valve assembly?
TPR valve
134
What must be done to PEX tubing when connecting it to a water heater?
Use a transitional fitting to attach it.
135
True or False: PEX tubing can be directly connected to gas- or oil-fired water heaters.
False
136
What should be done after connecting water pipes during installation?
Flush the lines to dislodge any debris.
137
What is a dirt leg in gas piping?
A short leg of vertical pipe just upstream from unit connections to act as a cleanout.
138
How can gas-line connections be checked for leaks?
By spraying soapy water on joints and looking for active bubbling.
139
What should the vent pipe be covered with on the outside?
A rubber flange
140
What is the recommended vent pipe pitch for a tankless water heater?
1⁄4-in.-per-ft. downward toward the exterior.
141
What equipment is needed to check the hot water temperature after installation?
Digital thermometer
142
What is the function of the combustion fan in a tankless water heater?
Pulls air into the burner and expels exhaust gases.
143
What should be done to the termination of the vent pipe to prevent rain damage?
Fit the top of the mounting plate under the siding course above and over siding courses below.
144
What type of gas piping is more easily routed than galvanized or black steel piping?
CSST (Corrugated Stainless Steel Tubing)
145
Fill in the blank: The __________ valve should be installed on the outtake of the tankless unit.
Temperature- and pressure-relief (TPR)
