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Water Heaters — ICC P1 Practice Questions

15 questions · 12% of the ICC P1 exam

Worked questions

1. A gas water heater is being replaced in an existing home. The installer is considering using a direct-vent water heater. What is the minimum venting distance from the water heater to the building exterior?

  • A3 feet
  • 5 feet
  • C7 feet
  • D10 feet

Exam tip

Direct-vent water heaters require specific venting requirements to ensure safe operation.

Why B is correct

According to Section R1009.6.1 of the 2024 IRC, the minimum venting distance from a direct-vent water heater to the building exterior is 5 feet. This is to ensure proper ventilation and prevent carbon monoxide buildup.

2. A family of four is selecting a storage water heater. Which comparison is most useful for checking whether it can meet their busiest hour of hot-water use?

  • ACompare the heater height with the room height, without considering demand
  • BChoose only by the tank diameter
  • Compare the first-hour rating with the household’s estimated peak-hour hot-water demand
  • DUse the number of bathrooms alone, without considering how they are used

Where to look it up

https://www1.eere.energy.gov/buildings/publications/pdfs/building_america/26465.pdf

Why C is correct

Estimate how much hot water the household needs during its busiest hour and compare that demand with the storage heater’s first-hour rating. That rating reflects both stored water and the heater’s ability to heat incoming water. Bathroom count can inform usage estimates, but does not describe the timing or amount of use by itself. Physical dimensions matter for installation fit and are not a substitute for this performance comparison. Source: https://www1.eere.energy.gov/buildings/publications/pdfs/building_america/26465.pdf

3. A storage-water-heater sizing review gives a calculated peak-hour hot-water demand of 54 gallons. Four candidate models have first-hour ratings of 48, 55, 65 and 75 gallons. Which is the lowest first-hour rating that meets this demand criterion?

  • 55 gallons
  • B48 gallons
  • C65 gallons
  • D75 gallons

Where to look it up

https://basc.pnnl.gov/redcalc/tool/dhw-first-hour-rating

Why A is correct

PNNL recommends a first-hour rating at least equal to calculated peak-hour demand. Of these ratings, 55 is the lowest that meets 54. First-hour delivery is not tank volume; this comparison alone does not approve all installation or sizing requirements. Source: https://basc.pnnl.gov/redcalc/tool/dhw-first-hour-rating

4. A replacement gas water heater must obtain its combustion air from outdoors rather than from the room where it is installed. Which venting configuration is designed to provide that outside-air intake and discharge combustion products outdoors?

  • ANatural draft
  • BPower vent
  • Direct vent
  • DIndirect vent

Where to look it up

https://www.hotwater.com/info-center/water-heater-venting.html

Why C is correct

A direct-vent configuration takes combustion air from outside and sends exhaust outside. A power-vent exhaust fan alone does not establish that combustion air comes from outdoors; power-direct-vent systems combine outside-air intake with powered venting. Select a listed appliance and follow its model-specific intake, exhaust and clearance requirements. The condition here is the source of combustion air, not simply whether the exhaust has a fan. Source: https://www.hotwater.com/info-center/water-heater-venting.html

5. A water heater is being installed in a residential garage. What is the minimum clearance required between the water heater and the nearest fuel supply line?

  • A6 inches
  • 12 inches
  • C18 inches
  • D24 inches

Exam tip

Always check the specific requirements for water heater installation in different locations as they can vary.

Why B is correct

According to Section R1009.4.1 of the 2024 IRC, the minimum clearance between a water heater and the nearest fuel supply line in a garage is 12 inches. This ensures safe installation and operation.

10 more in the bank

Answers and explanations for these are in the app.

  • A builder is looking to increase the energy efficiency of a new residential building. Which of the following water heater features would most significantly reduce energy consumption?
  • A code inspector is reviewing the plans for a new residential building. Which section of the International Residential Code (IRC) covers the installation requirements for water heaters?
  • A contractor is installing a water heater in a new residential building. The building is in a seismic zone. Which fuel type is recommended for the water heater to ensure safety?
  • A home inspector is conducting a routine inspection and notices a water heater with a rusted TPR valve. What action should the inspector take?
  • A homeowner is considering replacing an old water heater. What is the minimum energy factor (EF) required for a water heater in a residential application?
  • A new water heater is being installed in a residential building. What is the minimum temperature and pressure relief valve (TPR valve) capacity required?
  • A plumber is installing a new electric water heater in a residential building. The water heater is equipped with a temperature and pressure relief (TPR) valve. Which of the following is the correct location for the TPR valve discharge pipe?
  • A plumber is installing a new gas water heater in a remodeled kitchen. The existing venting system is copper piping. Which of the following is the correct vent material for a gas water heater?
  • A plumber is performing maintenance on a water heater. Which of the following maintenance tasks is most important for ensuring the longevity of the water heater?
  • A water heater in an existing home requires venting repairs. Which material is required for the vent pipe installation?

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