Service, Repair & Remodel — California C-36 Practice Questions

44 questions · 19% of the C-36 Plumbing Trade exam

Worked questions

1. A main shutoff will not fully close before valve replacement. What is the safe plan?

ACut the pressurized pipe quickly
Establish reliable upstream isolation and controlled drain-down
CRely on the failed valve
DHeat the wet pressurized joint

Why B is correct

Verification of isolation, pressure relief, drainage destination, affected occupants, backup controls, and emergency restoration prevents flooding and injury. A leaking valve is not dependable isolation.

2. After low-flow fixtures are installed, a remote shower has unstable temperature. What should be investigated?

Valve compatibility, pressure balance, flow, and hot-water delivery
BIncrease drain size only
CRemove the shower trap
DDisable all temperature limits

Why A is correct

A retrofit changes flow and may expose minimum-flow, pressure imbalance, recirculation, heater, cartridge, or piping issues. Measurements should identify the cause while preserving scald protection.

3. On a single-family remodel while preparing a change order, remodel work may disturb old pipe insulation suspected to contain asbestos; what should the plumbing contractor do?

ATest it by burning a sample
Stop and use qualified abatement
CWet it and remove it without controls
DHide it behind new drywall

Why B is correct

Suspect hazardous material requires controlled handling by qualified parties; casual disturbance can expose workers and occupants. The best answer is therefore “Stop disturbance and use the required qualified assessment and abatement process.” The other choices either address a different system, rely on an unsafe shortcut, or make a conclusion not supported by the stated facts.

4. A chemical hose station can backpressure the potable system and its protective device is unknown. What should occur before use?

ALower the water-heater temperature
BRely on the hose nozzle
Identify the hazard level and install or restore the approved protection before use
DAssume a check valve inside the faucet is sufficient for the described plumbing system and documented site conditions

Why C is correct

The best answer is: Identify the hazard level and install or restore the approved protection before use. Chemical exposure can contaminate the potable system through backsiphonage or backpressure. Protection must match the actual hazard and be installed, tested, and accessible as required; assumptions about an ordinary hose fitting are unsafe. The transferred field condition applies the same plumbing design, installation, service, or safety principle to a different project setting. The alternatives omit a prerequisite, conflict with the approved method, or fail to control the stated sanitation or physical hazard.

5. Multiple pinholes develop near earlier copper repairs. What underlying mechanism should be evaluated before another spot repair?

Evaluate the corrosion mechanism
BJoin incompatible metals directly
CPatch only the visible hole forever
DRaise water velocity

Why A is correct

The best answer is: Evaluate the corrosion mechanism. Repeated failures may reflect water chemistry, velocity, electrical effects, workmanship, erosion, or uniform aging. Sampling, history, wall condition, and system layout distinguish a local defect from systemic risk. The transferred field condition applies the same plumbing design, installation, service, or safety principle to a different project setting. The alternatives omit a prerequisite, conflict with the approved method, or fail to control the stated sanitation or physical hazard.

6. The same building-drain location blocks every few months. What should follow temporary restoration of flow?

AReduce every fixture flow
BUse progressively stronger acid
CSchedule endless routine cabling for the described plumbing system and documented site conditions
Inspect and locate the underlying defect before choosing repair

Why D is correct

The best answer is: Inspect and locate the underlying defect before choosing repair. Repeated blockage can result from offset joints, roots, belly, damage, grease, or improper grade. Camera inspection, locating, records, and flow evidence support a targeted repair instead of repeated symptoms treatment. The transferred field condition applies the same plumbing design, installation, service, or safety principle to a different project setting. The alternatives omit a prerequisite, conflict with the approved method, or fail to control the stated sanitation or physical hazard.

38 more in the bank

Answers and explanations for these are in the app.

A boiler makeup connection has an unknown backflow device with no test records. What is the appropriate response?
A building drain repeatedly clogs at the same location. What is the best next step after restoring flow?
A drain-cleaning cable binds and repeatedly returns damaged from an unknown obstruction. What is the safe next step?
A gas water heater produces soot and unstable flame. What should the plumber do first?
A hose connection used with chemical equipment has no verified backflow protection. What should the service plumber do?
A pinhole leak appears in a copper system with several prior repairs. What should guide the response?
A water meter moves when occupants report all fixtures off. What is the best first diagnostic approach?
After replacing a concealed leaking branch, what should occur before the wall is closed?
An occupied room has intermittent sewer odor, but visible fixture traps contain water. What should be checked next?
An opened wall reveals an unvented fixture and damaged drainage fitting. What should happen before concealment?
On a community-center project at final inspection, a repair joins dissimilar piping materials; what is the correct approach?
On a hotel renovation at final inspection, a relocated island sink cannot use the former wall vent path; what should the remodel plan do?
On a light-industrial addition at final inspection, a cable repeatedly stops at the same point and returns covered with roots; what recommendation is appropriate?
On a office renovation at final inspection, a concealed leak is suspected after the meter moves with all fixtures off; what is the sound next step?
On a restaurant build-out while preparing a change order, a customer reports low flow only at one faucet while nearby fixtures perform normally; what should be checked first?
On a small hospital renovation while preparing a change order, a repair expands into relocation of drainage and structural penetrations; what should happen before proceeding?
On a tenant improvement while preparing a change order, quick-closing valves cause loud banging after a remodel; what should be investigated?
Removed pipe coating is suspected to contain regulated hazardous material. How should disposal be planned?
Upper-floor fixtures have low pressure only during peak use. What should be measured?
A boiler makeup line contains an unidentified device with no test history. What must be verified about protection?
A building main valve will not fully stop flow before planned replacement. What isolation and drain-down plan is required?
A concealed branch repair is complete but has not been tested. What must happen before finishes are restored?
A gas water heater produces unstable yellow flame and soot. What is the first safe service decision?
A meter indicates continuing use after occupants close all known fixtures. How should branches and equipment be isolated?
A “minor repair” develops into relocated drains and new structural openings. What approvals and documentation should be resolved before continuing?
A powered drain cable repeatedly kinks at an unidentified obstruction. What is the safe next diagnostic step?
A relocated island sink no longer reaches its former wall vent. Which code-compliant vent strategy must the remodel provide?
A repair joins copper tube to a different piping material in a wet location. What connection method should be used?
A retrofit shower valve cannot hold temperature after low-flow trim is installed. Which compatibility and delivery factors need diagnosis?
A sewer cable repeatedly meets the same resistance and brings back roots. What follow-up is appropriate after flow is restored?
Old thermal insulation breaks apart when a plumber reaches a concealed valve. What should happen before disturbance continues?
Only one lavatory has low flow while adjacent fixtures remain normal. Which local restrictions should be checked first?
Opening a wall reveals an unvented fixture and a cracked drainage fitting. When should correction occur?
Rapid-closing laundry valves create severe pressure shock after remodeling. Which control should be investigated?
Removed pipe coating may be regulated hazardous waste. Which handling and disposal process should be used?
Sewer odor persists even though visible traps contain water. Which concealed drain and vent paths should be investigated?
Upper floors lose pressure only when several fixtures operate. Which paired pressure readings are most useful?
With all fixtures reportedly off, a building meter still advances. Which non-destructive diagnostic step should precede opening walls?

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