ASHI Plumbing, Electrical & HVAC Systems 2 — Questions and Answers
Question 1: What is the minimum required slope for a horizontal drain pipe in a residential plumbing system?
- 1/16 inch per foot
- 1/8 inch per foot
- 1/4 inch per foot (Correct answer)
- 1/2 inch per foot
Correct answer: 1/4 inch per foot
Horizontal drain pipes require a minimum slope of 1/4 inch per foot to ensure adequate flow and self-cleaning velocity.
Question 2: During a home inspection, you observe a water heater flue pipe with a 1-inch clearance to combustibles. What is the correct action?
- Note it as acceptable since 1 inch is sufficient
- Report it as a safety hazard requiring correction (Correct answer)
- Test the flue draw before making a determination
- Only report it if the water heater is over 10 years old
Correct answer: Report it as a safety hazard requiring correction
Single-wall flue pipes must maintain at least 6 inches of clearance from combustibles, making 1 inch a reportable fire hazard.
Question 3: A 200-amp residential electrical service panel is inspected and found to have double-tapped breakers. Which statement is most accurate?
- Double-tapping is always a code violation regardless of breaker type
- Double-tapping is acceptable on any breaker rated 30 amps or above
- Some breakers are listed for double-tapping; the inspector should note it and defer to an electrician (Correct answer)
- Double-tapping is only a concern on GFCI breakers
Correct answer: Some breakers are listed for double-tapping; the inspector should note it and defer to an electrician
Certain breakers (e.g., Square D QO series) are listed to accept two conductors, so an inspector should note the condition and recommend electrician evaluation.
Question 4: What does a high-pitched squealing noise from an HVAC air handler most commonly indicate?
- Refrigerant overcharge
- Failing blower motor bearings (Correct answer)
- Dirty evaporator coil
- Blocked condensate drain
Correct answer: Failing blower motor bearings
A high-pitched squeal from an air handler typically signals worn or failing blower motor bearings requiring service.
Question 5: Which pipe material is identified by its purple/lavender color and is commonly found in older mobile homes?
- CPVC
- PEX
- Polybutylene (Correct answer)
- ABS
Correct answer: Polybutylene
Polybutylene pipe, often gray but sometimes marked with purple fittings, was widely used 1978–1995 and is known for premature failure.
Question 6: An inspector finds a GFCI outlet in a bathroom that does not trip when tested. What should the inspector report?
- The outlet is functioning correctly if it still provides power
- The GFCI protection is non-functional and should be evaluated by an electrician (Correct answer)
- GFCI outlets in bathrooms are optional under older codes
- Only report if the outlet shows visible damage
Correct answer: The GFCI protection is non-functional and should be evaluated by an electrician
A GFCI that fails to trip when tested is not providing shock protection and must be reported as a safety deficiency.
Question 7: What is the primary function of a pressure-balancing valve in a shower?
- To limit maximum water flow rate
- To prevent scalding when a toilet is flushed by maintaining temperature balance (Correct answer)
- To reduce water hammer in supply lines
- To regulate hot water heater pressure
Correct answer: To prevent scalding when a toilet is flushed by maintaining temperature balance
A pressure-balancing valve maintains a set ratio of hot to cold water so a sudden pressure drop (e.g., toilet flush) does not cause scalding.
ASHI Plumbing, Electrical & HVAC Systems 2
What is the minimum required slope for a horizontal drain pipe in a residential plumbing system?