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AL Plumber practice questions

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Question 1General Regulations, Definitions, and Code Administration

Under the plumbing code, which of the following is part of the plumbing system of a building?

  1. The branch circuit that supplies a water heater
  2. The landscaping and grading around a building
  3. Water-supply piping inside a building Correct answer.
  4. The painting and caulking of plumbing fixtures

Explanation

Plumbing covers the water-supply and drainage piping, fixtures, appurtenances, and related components installed in or adjacent to a building. Electrical circuits, protective coatings, and site grading fall under other trades or other code chapters.

Question 2General Regulations, Definitions, and Code Administration

Before beginning most plumbing installations, the person doing the work must first:

  1. Have the project plans notarized before starting
  2. Obtain a permit Correct answer.
  3. Notify the water utility in writing before starting
  4. Post the license number at the street frontage

Explanation

The code requires a permit to be obtained from the authority having jurisdiction before regulated plumbing work begins. The permit allows inspections to be scheduled as the work progresses.

Question 3General Regulations, Definitions, and Code Administration

In the code, a material or method that is "approved" is one that:

  1. carries a listing mark from any laboratory
  2. meets all the manufacturer's warranty terms
  3. has been used locally for over ten years
  4. is accepted by the building official Correct answer.

Explanation

Approval is granted by the authority having jurisdiction, which accepts materials, equipment, and methods that conform to the code. Listing by a recognized agency is evidence the AHJ may consider, but approval itself rests with the official.

Question 4General Regulations, Definitions, and Code Administration

"Potable water" means water that is:

  1. Safe for human consumption Correct answer.
  2. Delivered under continuous pressure
  3. Free of visible sediment or cloudiness
  4. Available from a public water utility

Explanation

Potable water is water free from impurities in amounts sufficient to cause disease or harmful physiological effects, making it safe for drinking and culinary use. Source, clarity, and pressure do not by themselves establish potability.

Question 5General Regulations, Definitions, and Code Administration

The "authority having jurisdiction" is the person or agency that:

  1. writes the manufacturer's installation instructions
  2. supplies drinking water to the building
  3. certifies plumbing fixtures for listing
  4. enforces the code Correct answer.

Explanation

The authority having jurisdiction is the organization, office, or individual responsible for enforcing the code and approving installations. Inspectors and building officials act for that authority.

Question 6General Regulations, Definitions, and Code Administration

Drainage piping that will be concealed in a wall must be tested and inspected:

  1. within 30 days of the final inspection
  2. after the wall is closed and finished
  3. only if the building is new construction
  4. before it is covered or concealed Correct answer.

Explanation

The code requires that work be inspected and approved before it is concealed, because once covered it cannot be examined. The installer must request inspection in time to avoid covering untested work.

Question 7General Regulations, Definitions, and Code Administration

In Alabama, an apprentice plumber may perform plumbing work only:

  1. on single-family dwellings with no supervision at all
  2. under a licensed journeyman or master plumber Correct answer.
  3. after passing the journeyman licensing examination
  4. whenever the building official is on the site

Explanation

Apprentices learn the trade while working under the supervision of a licensed journeyman or master plumber. Unsupervised plumbing work is reserved for properly licensed individuals.

Question 8General Regulations, Definitions, and Code Administration

The building drain is the lowest piping of the drainage system and extends:

  1. to the building sewer outside the wall Correct answer.
  2. vertically from the roof to the foundation
  3. from the water meter to the first fixture
  4. from the property line to the public sewer main

Explanation

The building drain receives the waste from inside the building and carries it to a point outside the building wall, where the building sewer begins. The building sewer then continues to the public sewer or private disposal system.

Question 9General Regulations, Definitions, and Code Administration

A cross-connection is a connection between:

  1. a potable supply and a contamination source Correct answer.
  2. a fixture drain and the individual vent serving it
  3. two drainage stacks of different diameters
  4. a water heater and its temperature relief valve

Explanation

A cross-connection is any actual or potential link between a potable water system and a source of contamination or pollution. Such connections must be eliminated or protected by an approved backflow preventer.

Question 10General Regulations, Definitions, and Code Administration

Responsibility for keeping the plumbing system in an existing building safe and sanitary rests with:

  1. the owner or the owner's agent Correct answer.
  2. the contractor who installed it, permanently
  3. the building official
  4. the water utility that serves the property

Explanation

The code places the duty to maintain plumbing in a safe, sanitary, and functional condition on the owner or the owner's designated agent. The building official enforces the code but does not maintain private systems.

Question 11General Regulations, Definitions, and Code Administration

On a project in Alabama, the master plumber of record is generally the person who:

  1. inspects completed work for the board
  2. holds the license responsible for the work Correct answer.
  3. is enrolled in a supervised training program
  4. performs fixture service work only, without permits

Explanation

The master plumber holds the license under which plumbing work and permits are obtained and is accountable for the work performed. Journeymen and apprentices work under that authority.

Question 12General Regulations, Definitions, and Code Administration

The flood level rim of a fixture is:

  1. the highest vent opening on the stack
  2. the top of the trap weir inside the fixture
  3. the outlet of the fixture drain
  4. the rim where water would overflow Correct answer.

Explanation

The flood level rim is the edge of the receptacle from which water overflows onto the floor. It establishes the elevation used for setting flood-level requirements such as backwater valves and fixture openings.

Question 13General Regulations, Definitions, and Code Administration

When a permit applicant disagrees with the building official's interpretation of the code, the usual first step is to:

  1. ask the water utility to overrule the official
  2. appeal to the board of appeals Correct answer.
  3. file a lien against the property owner
  4. install the work and request a variance afterward

Explanation

The code provides a board of appeals to hear challenges to decisions of the building official. Work should not proceed while the appeal is pending unless the official allows it.

Question 14General Regulations, Definitions, and Code Administration

A building official may grant a variance from a code provision when:

  1. no neighboring owner objects to the variance
  2. the contractor agrees to a higher permit fee
  3. a licensed master plumber performs the work
  4. genuine practical difficulty exists Correct answer.

Explanation

Variances are limited to situations of practical difficulty where the intent and safety objectives of the code can still be met. The decision rests with the authority or its board of appeals, not with fees or neighbors.

Question 15General Regulations, Definitions, and Code Administration

A fixture unit is a measure of:

  1. the volume of water a fixture holds in gallons
  2. the weight of a fixture in pounds when filled
  3. the number of fixtures connected to a branch
  4. the load a fixture places on the system Correct answer.

Explanation

Fixture units express the probable load a fixture imposes on the drainage or water-supply system, accounting for use frequency as well as flow. Tables assign fixture-unit values used to size pipe.

Question 16General Regulations, Definitions, and Code Administration

When work that requires a permit has started without one, the building official is authorized to:

  1. approve the work if it appears acceptable
  2. stop the work until a permit is obtained Correct answer.
  3. take no action until the work is finished
  4. issue the permit retroactively without charge

Explanation

The code authorizes the building official to halt work that is proceeding without a required permit. The work may resume only after the permit is obtained and the required inspections are made.

Question 17Plumbing Mathematics, Plan Reading, and Isometric Drawings

A dimension on a plumbing drawing reads 7'-9". What is this length expressed in decimal feet?

  1. 7.09 ft
  2. 8.25 ft
  3. 7.90 ft
  4. 7.75 ft Correct answer.

Explanation

To convert inches to a decimal part of a foot, divide the inches by 12. Here 9 ÷ 12 = 0.75, so 7'-9" equals 7.75 ft.

Question 18Plumbing Mathematics, Plan Reading, and Isometric Drawings

A floor plan is drawn at a scale of 1/4 inch = 1 foot. A horizontal pipe run measures 3 1/2 inches on the drawing. What is the actual length of the run?

  1. 14 ft Correct answer.
  2. 3 ft 6 in
  3. 21 ft
  4. 7 ft

Explanation

At 1/4 inch per foot, each 1/4 inch on the drawing represents 1 foot, so the drawn length is divided by 0.25. Dividing 3.5 in by 0.25 in/ft gives 14 ft.

Question 19Plumbing Mathematics, Plan Reading, and Isometric Drawings

On a plumbing isometric drawing, what do the vertical lines represent?

  1. Vertical risers Correct answer.
  2. The direction of flow in the drain
  3. Horizontal branch runs between fixtures
  4. Pipe that is buried below the slab

Explanation

An isometric shows the three dimensions of a piping system on one view: vertical lines represent risers and other vertical pipe, while angled lines represent horizontal runs. Depth below slab or grade is conveyed by elevation notes, not by line orientation.

Question 20Plumbing Mathematics, Plan Reading, and Isometric Drawings

A 3-inch horizontal drain is installed at a slope of 1/4 inch per foot. How much does the pipe invert drop over a 16-foot run?

  1. 4 inches Correct answer.
  2. 6 inches
  3. 3 inches
  4. 2 inches

Explanation

The total fall equals the slope multiplied by the length of the run. Multiplying 1/4 inch per foot by 16 ft gives 4 inches of fall.

Question 21Plumbing Mathematics, Plan Reading, and Isometric Drawings

A pipe must offset 10 inches using two 45-degree elbows. What is the travel, that is, the center-to-center length of the diagonal section between the fittings?

  1. 20.0 in
  2. 12.0 in
  3. 10.0 in
  4. 14.1 in Correct answer.

Explanation

For a 45-degree offset, the travel equals the offset multiplied by 1.414. Multiplying 10 in by 1.414 gives about 14.1 in.

Question 22Plumbing Mathematics, Plan Reading, and Isometric Drawings

A column of water is 35 feet high. Using 0.433 psi per foot of water, what static pressure does the column produce at its base?

  1. 35 psi
  2. 80.8 psi
  3. 8.1 psi
  4. 15.2 psi Correct answer.

Explanation

Static pressure from a head of water equals the height in feet multiplied by 0.433 psi per foot. Multiplying 35 ft by 0.433 psi/ft gives about 15.2 psi.

Question 23Plumbing Mathematics, Plan Reading, and Isometric Drawings

How many gallons of water are contained in 40 feet of 3-inch-diameter pipe? Use 1 cubic foot = 7.48 gallons.

  1. 58.7 gallons
  2. 3.7 gallons
  3. 1.96 gallons
  4. 14.7 gallons Correct answer.

Explanation

Convert the diameter to feet (3 in = 0.25 ft), so the radius is 0.125 ft. The volume is π × 0.125² × 40 = 1.96 ft³, and 1.96 × 7.48 = about 14.7 gallons.

Question 24Plumbing Mathematics, Plan Reading, and Isometric Drawings

A drain falls 3 inches over a horizontal run of 25 feet. What is the slope expressed as a percent?

  1. 12%
  2. 8.3%
  3. 1.0% Correct answer.
  4. 3%

Explanation

Percent slope is the fall divided by the horizontal run, with both measured in the same units. Converting the run to inches gives 300 in, so 3 ÷ 300 = 0.01, or 1.0 percent.

Question 25Plumbing Mathematics, Plan Reading, and Isometric Drawings

A dimension line on a floor plan shows an overall distance of 12'-4" between two walls. Two intermediate dimensions along the same line read 5'-0" and 4'-6". What is the remaining dimension?

  1. 2'-4"
  2. 2'-10" Correct answer.
  3. 3'-4"
  4. 1'-10"

Explanation

Convert the overall distance to inches (148 in) and subtract the intermediate dimensions (60 in and 54 in). The remainder is 34 in, which equals 2'-10".

Question 26Plumbing Mathematics, Plan Reading, and Isometric Drawings

Fixture-unit values are 3 for a water closet, 1 for a lavatory, 2 for a bathtub, and 2 for a kitchen sink. What is the total load, in fixture units, for 2 water closets, 3 lavatories, 1 bathtub, and 1 kitchen sink?

  1. 13 fixture units Correct answer.
  2. 11 fixture units
  3. 9 fixture units
  4. 15 fixture units

Explanation

Multiply each fixture count by its unit value and add the results: (2 × 3) + (3 × 1) + (1 × 2) + (1 × 2). This gives 6 + 3 + 2 + 2 = 13 fixture units.

Question 27Plumbing Mathematics, Plan Reading, and Isometric Drawings

A building drain leaves a structure with an invert elevation of 98.50 ft and runs 60 ft at a slope of 1/4 inch per foot. What is the invert elevation at the downstream end?

  1. 99.75 ft
  2. 97.75 ft
  3. 96.25 ft
  4. 97.25 ft Correct answer.

Explanation

The total fall is 60 ft × 0.25 in/ft = 15 in, which equals 1.25 ft. Because the pipe slopes downward, subtract this fall from the starting invert: 98.50 − 1.25 = 97.25 ft.

Question 28Plumbing Mathematics, Plan Reading, and Isometric Drawings

Two pipes are joined with 45-degree elbows in a rolling offset. The offset measures 9 inches in one plane and 12 inches in the perpendicular plane. What is the travel length of the diagonal section?

  1. 17.0 in
  2. 21.2 in Correct answer.
  3. 29.7 in
  4. 15.0 in

Explanation

First find the true offset with the Pythagorean theorem: the square root of (9² + 12²) is 15 in. For 45-degree fittings, multiply the true offset by 1.414 to get a travel of about 21.2 in.

Question 29Plumbing Mathematics, Plan Reading, and Isometric Drawings

An isometric shows a lavatory branch with a 4-foot horizontal run, an 18-inch vertical drop to the drain line, and then a 6-foot horizontal run to the stack. If 4 inches of pipe is allowed for each of the two fittings, what total length of pipe should be ordered?

  1. 10'-10"
  2. 11'-6"
  3. 13'-0"
  4. 12'-2" Correct answer.

Explanation

Add the measured runs, converting the riser to feet: 4 + 1.5 + 6 = 11.5 ft, or 138 in. Add the fitting allowance of 4 in per fitting (8 in total) to get 146 in, which is 12'-2".

Question 30Plumbing Mathematics, Plan Reading, and Isometric Drawings

A rectangular sump pit measures 2 feet long, 1.5 feet wide, and 2 feet deep. How many gallons will it hold? Use 1 cubic foot = 7.48 gallons.

  1. 6.0 gallons
  2. 89.8 gallons
  3. 22.4 gallons
  4. 44.9 gallons Correct answer.

Explanation

The volume of a rectangular pit is length × width × depth: 2 × 1.5 × 2 = 6 ft³. Multiplying 6 ft³ by 7.48 gallons per cubic foot gives about 44.9 gallons.

Question 31Plumbing Fixtures, Fixture Fittings, and Appliances

What is the minimum required depth of the liquid seal in a fixture trap?

  1. 2 inches Correct answer.
  2. 1 inch
  3. 4 inches
  4. 6 inches

Explanation

A fixture trap must hold a liquid seal deep enough to resist sewer gas but shallow enough to be cleared by the fixture's flow; the standard minimum is 2 inches, measured from the crown weir to the dip. The same rule caps the seal at 4 inches.

Question 32Plumbing Fixtures, Fixture Fittings, and Appliances

What is the purpose of the wax ring when setting a tank-type water closet?

  1. To cushion the bowl so it will not crack when the bolts are tightened
  2. To seal the joint between the bowl outlet and the closet flange Correct answer.
  3. To carry the weight of the bowl on the flange
  4. To anchor the bowl to the floor flange

Explanation

The wax ring is a compressible gasket that seals the gap between the horn of the closet bowl and the upstanding hub of the closet flange. It prevents water and sewer gas from escaping at that joint.

Question 33Plumbing Fixtures, Fixture Fittings, and Appliances

What does a faucet aerator do at the outlet of a lavatory faucet?

  1. It raises the flow rate of the faucet
  2. It prevents backflow into the potable water system
  3. It mixes air into the water stream and reduces splashing Correct answer.
  4. It filters sediment out of the water supply

Explanation

An aerator is a screened fitting at the spout that draws air into the stream, producing a soft, non-splashing flow while maintaining an acceptable flow rate. It also acts as the flow-restricting element that keeps the faucet within its rated gallons per minute.

Question 34Plumbing Fixtures, Fixture Fittings, and Appliances

What is the function of the temperature and pressure relief valve on a storage-type water heater?

  1. It drains the tank for servicing
  2. It shuts off the gas supply if the pilot goes out
  3. It releases water when tank temperature or pressure exceeds safe limits Correct answer.
  4. It admits air to the tank to prevent a vacuum

Explanation

The T&P valve is a safety device that opens when internal pressure or temperature rises above its set point, discharging water to relieve the condition before the tank can rupture. Its discharge must be piped to a safe point of disposal.

Question 35Plumbing Fixtures, Fixture Fittings, and Appliances

Which fitting is installed at a shower to limit sudden temperature changes caused by pressure fluctuations in the supply?

  1. A swing check valve
  2. A pressure-balancing mixing valve Correct answer.
  3. A gate valve
  4. A vacuum breaker

Explanation

A pressure-balancing valve senses changes in hot and cold supply pressure and shifts internally to hold the outlet temperature nearly constant, reducing the chance of a scald if a nearby fixture is used. Thermostatic mixing valves perform a similar scald-prevention function.

Question 36Plumbing Fixtures, Fixture Fittings, and Appliances

On a tank-type water closet, what opens to release water from the tank into the bowl when the handle is pressed?

  1. The fill valve
  2. The flush valve flapper Correct answer.
  3. The fixture supply stop
  4. The overflow tube

Explanation

Pressing the handle lifts the flapper (or flush valve seal) off the flush valve seat, letting tank water rush into the bowl through the rim and jet openings. The flapper then settles back onto the seat to allow the tank to refill.

Question 37Plumbing Fixtures, Fixture Fittings, and Appliances

Under federal efficiency standards, what is the maximum flow rate for a lavatory faucet at 60 psi?

  1. 1.5 gallons per minute
  2. 2.2 gallons per minute Correct answer.
  3. 3.0 gallons per minute
  4. 1.0 gallon per minute

Explanation

Lavatory faucets are limited to 2.2 gallons per minute at 60 psi, and the same limit applies to kitchen faucets. Replacement aerators and showerheads must also carry ratings that keep the fixture within the standard.

Question 38Plumbing Fixtures, Fixture Fittings, and Appliances

What is the maximum flow rate permitted for a showerhead at 80 psi?

  1. 1.2 gallons per minute
  2. 2.5 gallons per minute Correct answer.
  3. 2.0 gallons per minute
  4. 1.6 gallons per minute

Explanation

Showerheads are limited to 2.5 gallons per minute at 80 psi under federal standards. Multiple showerheads fed from one valve are evaluated together against that limit.

Question 39Plumbing Fixtures, Fixture Fittings, and Appliances

What is the maximum flush volume allowed for a new tank-type water closet sold in the United States?

  1. 3.5 gallons per flush
  2. 1.6 gallons per flush Correct answer.
  3. 1.0 gallon per flush
  4. 2.5 gallons per flush

Explanation

New tank-type water closets are limited to 1.6 gallons per flush. Older 3.5 gallon and 5 gallon closets predate the standard, and high-efficiency models use 1.28 gallons or less.

Question 40Plumbing Fixtures, Fixture Fittings, and Appliances

Why must a dishwasher drain hose be elevated to a high loop or run through an air gap before connecting to the sink waste?

  1. To vent sewer gas out of the dishwasher drain
  2. To speed up the drain cycle of the dishwasher
  3. To prevent waste water from siphoning back into the dishwasher Correct answer.
  4. To trap food particles before they reach the sink drain

Explanation

The dishwasher drain connects to the waste system, which is a potential cross-connection. A high loop or air gap keeps the hose outlet above the flood level rim of the sink so that a backup or loss of pressure cannot draw dirty water back into the appliance.

Question 41Plumbing Fixtures, Fixture Fittings, and Appliances

A clothes washer standpipe must extend above the trap weir a distance of:

  1. 12 to 18 inches
  2. 18 to 42 inches Correct answer.
  3. 48 to 60 inches
  4. 6 to 12 inches

Explanation

The standpipe must be long enough that the washer's discharge hose is not submerged and short enough that the hose can still reach; the usual range is 18 to 42 inches above the trap weir. The standpipe must also be trapped and vented.

Question 42Plumbing Fixtures, Fixture Fittings, and Appliances

What is the function of the waste and overflow assembly on a bathtub?

  1. It drains the tub and limits the water level in the tub Correct answer.
  2. It vents the tub trap to the vent stack
  3. It protects the potable water supply from backflow
  4. It provides the mounting point for the shower valve

Explanation

The overflow opening at the tub rim and the drain outlet at the bottom connect through the overflow assembly to the tub trap. The overflow lets excess water escape before the tub overflows and also admits air so the tub drains freely.

Question 43Plumbing Fixtures, Fixture Fittings, and Appliances

What is the purpose of a trap primer connected to a floor drain?

  1. It adds water to the trap to keep the seal from evaporating Correct answer.
  2. It provides a cleanout opening in the drain line
  3. It keeps debris from entering the drain body
  4. It increases the flow capacity of the drain

Explanation

A floor drain that sees little use can lose its trap seal to evaporation, allowing sewer gas into the building. A trap primer delivers a small amount of water to the trap periodically so the seal stays intact.

Question 44Plumbing Fixtures, Fixture Fittings, and Appliances

A water heater installed where a leak could damage the structure must have a drain pan that:

  1. Is at least 12 inches deep with no outlet
  2. May be omitted if a relief valve is installed
  3. Is piped directly to the building sewer
  4. Has a drain piped to an indirect waste receptor Correct answer.

Explanation

The pan must have a drain that discharges to an indirect waste receptor by gravity, so a leaking tank cannot flood the space. Indirect discharge keeps sewer gas and waste from backing up into the pan.

Question 45Plumbing Fixtures, Fixture Fittings, and Appliances

How should a water closet flange be installed relative to the finished floor?

  1. Flush with or slightly above the finished floor and anchored to the floor Correct answer.
  2. Set on top of the floor without fasteners, held in place by the wax ring
  3. Recessed at least 1 inch below the finished floor
  4. Attached to the bowl first and then screwed to the floor

Explanation

The flange should sit flush with or slightly above the finished floor so the wax ring can compress fully between the bowl horn and the flange. It must be fastened to the floor or to the drain piping so the closet bolts have a solid anchor.

Question 46Plumbing Fixtures, Fixture Fittings, and Appliances

Why does a kitchen faucet with a pull-out spray head require a backflow preventer in the faucet body?

  1. The cartridge can wear and allow hot water to cross over
  2. The aerator may clog and raise pressure in the body
  3. The spray hose reduces supply pressure at the outlet
  4. The spray head can be dropped below the sink rim Correct answer.

Explanation

A pull-out spray head on a flexible hose can be held below the flood level rim of the sink, creating a cross-connection with the potable supply. An integral vacuum breaker or check device in the faucet body prevents sink water from being siphoned back into the supply.

Question 47Plumbing Fixtures, Fixture Fittings, and Appliances

A sill cock with a threaded outlet is installed in a yard for hose connection. What device typically provides the required backflow protection?

  1. A double check valve installed at the water meter
  2. A pressure-reducing valve installed upstream
  3. A swing check valve installed in the hose
  4. An atmospheric vacuum breaker installed at the bibb Correct answer.

Explanation

A hose-connected sill cock is a cross-connection because the hose end can be left submerged or in a puddle. An atmospheric vacuum breaker on the discharge side of the bibb admits air and prevents back-siphonage when supply pressure drops; no shutoff may be installed downstream of the breaker.

Question 48Plumbing Fixtures, Fixture Fittings, and Appliances

A thermostatic mixing valve supplies a residential bathtub. What is the commonly required maximum delivered water temperature at the tub and shower fixtures?

  1. 110 degrees F
  2. 100 degrees F
  3. 140 degrees F
  4. 120 degrees F Correct answer.

Explanation

Hot water delivered to bathtub and shower fixtures is limited to about 120 degrees F to reduce scald risk, with tighter limits in some public or assisted-care settings. The mixing valve is adjusted and locked to hold that limit at the fixture.

Question 49Plumbing Fixtures, Fixture Fittings, and Appliances

How must the discharge pipe from a water heater relief valve terminate?

  1. Reduced to a 1/2-inch pipe to control flow
  2. Pitched upward to discharge outside the building
  3. Between 6 and 24 inches above the floor, unthreaded Correct answer.
  4. Threaded into a floor drain trap

Explanation

The relief valve discharge must run full size by gravity and terminate between 6 and 24 inches above the floor or a waste receptor, with a plain unthreaded end so it cannot be capped. It must not be trapped or reduced, and it must discharge where scalding water will not injure anyone.

Question 50Plumbing Fixtures, Fixture Fittings, and Appliances

A diaphragm-type flushometer valve on a water closet runs continuously and will not shut off. What is the most likely cause?

  1. A closed fixture angle stop
  2. A loose vacuum breaker on the branch
  3. A damaged diaphragm or a clogged bypass orifice Correct answer.
  4. A worn bowl fill tube

Explanation

In a diaphragm flushometer, water passes through a small bypass orifice to build pressure on top of the diaphragm and close the valve. Debris in the orifice or a torn or stiffened diaphragm prevents that pressure from developing, so the valve stays open; cleaning the orifice and replacing the diaphragm restores shutoff.