Utah HVAC Contractor (H100) Exam: Practice Test & Licensing Guide

Under the Division of Professional Licensing Act, licenses issued under Title 58 are issued on what renewal cycle?

Answer: Two-year cycle

Utah Code 58-1-308(1)(a) says each license issued under Title 58 is issued on a two-year renewal cycle set by rule. Subsection (1)(b) lets the Division lengthen or shorten a single renewal period by up to one year, but only to keep or change the cycle. That adjustment is where the one-year and three-year choices come from. The standard cycle is still two years.

Reference: Utah Code Title 58, Chapter 1 (Division of Professional Licensing Act), 58-1-308(1)

Which term, as defined in the DOPL general rule, means disciplinary action that removes the right to use a license for a period of time or indefinitely, with the possibility of later reinstatement?

Answer: Suspension

R156-1-102(28) defines "suspend" as disciplinary action that removes the right to use a license for a period or indefinitely, with the possibility of later reinstatement. "Revoke" in R156-1-102(27) extinguishes the license entirely. "Cancel" in R156-1-102(3) is nondisciplinary, for example for a license issued in error. A public reprimand, R156-1-102(22), is a formal censure that doesn't remove the right to practice.

Reference: Utah Admin. Code R156-1 (General Rule of the Division of Professional Licensing), R156-1-102(28)

Under the IMC, what minimum level working space must be provided in front of the control side of an appliance for service?

Answer: 30 inches deep by 30 inches wide

IMC 2024 Section 306.1 requires a level working space at least 30 inches deep and 30 inches wide in front of the control side of an appliance. The same 30 x 30 service space shows up again in 306.3 (attics) and 306.4 (under floors). The 36-inch figure is the door and passageway width for rooms containing appliances, from 306.2. It is not the working space.

Reference: 2024 International Mechanical Code (as adopted in Utah), Section 306.1

A house has a 600 cfm kitchen range hood. All of its fuel-burning appliances inside the air barrier are direct-vent or use mechanical draft venting. Under Utah's statewide IMC amendments, is makeup air required for the hood?

Answer: No, because Utah's added Section 505.4.1 waives makeup air in this situation

IMC 2024 Section 505.4 normally requires makeup air, roughly equal to the exhaust rate, for hood systems that can exhaust more than 400 cfm. Utah Code 15A-3-401(2) adds Section 505.4.1. It says makeup air is not required in residential dwelling units when all fuel-burning appliances inside the unit's air barrier are direct-vent or use mechanical draft venting. The Utah amendment controls. Without those appliance conditions, the 400-cfm rule would still apply.

Reference: Utah Code Title 15A, Chapter 3 (statewide amendments), 15A-3-401(2) (adds IMC Section 505.4.1)

Using IMC Equation 4-9, what minimum continuous outdoor airflow is required for a 2,400-square-foot dwelling unit with 3 bedrooms?

Answer: 102 cfm

IMC 2024 Section 403.3.2.1, Equation 4-9, gives Q = 0.03 × A(floor) + 7.5 × (N(br) + 1). The floor term is 0.03 × 2,400 = 72 cfm. The bedroom term is 7.5 × (3 + 1) = 30 cfm, so Q = 72 + 30 = 102 cfm. Stopping after the floor term gives 72 cfm. Using 7.5 × 3 without the +1 gives 94.5 cfm. Using 0.01 cfm per square foot, the older ASHRAE 62.2-2010 area rate, gives 24 + 30 = 54 cfm.

Reference: 2024 International Mechanical Code (as adopted in Utah), Section 403.3.2.1, Equation 4-9

A 10-ton chilled water coil is designed for a 10°F water temperature rise. Using the water-side equation Btu/h = 500 × gpm × ΔT, what flow rate is required?

Answer: 24 gpm

First convert the load: 10 tons × 12,000 Btu/h per ton = 120,000 Btu/h. Then gpm = Btu/h ÷ (500 × ΔT) = 120,000 ÷ (500 × 10) = 24 gpm. The factor 500 is 8.33 lb/gal × 60 min/h × 1 Btu/lb·°F. Using a 20°F rise gives 12 gpm and a 5°F rise gives 48 gpm. Plugging in tons without converting to Btu/h, and misplacing a decimal, gives 2.4 gpm.

Reference: Modern Refrigeration and Air Conditioning, 22nd ed., Hydronic and chilled-water systems: Btu/h = 500 × gpm × ΔT

Refrigerants in IMC Table 1103.1 are classified by ASHRAE 34 safety group. What does the safety group "A2L" (for example, R-454B or R-32) indicate?

Answer: Lower toxicity and lower flammability, with a low burning velocity

IMC 2024 Section 1103.1 classifies refrigerants by the ASHRAE 34 safety groups in Table 1103.1. The letter gives toxicity: A is lower toxicity and B is higher toxicity. The number gives flammability: 1 means no flame propagation, 2 and 3 are increasingly flammable, and the "L" subclass (2L) means lower flammability with a low burning velocity. A1, like R-410A, means lower toxicity with no flame propagation. A2L refrigerants like R-454B and R-32 are mildly flammable, which is why the code adds labeling and installation rules for them.

Reference: 2024 International Mechanical Code (as adopted in Utah), Section 1103.1 and Table 1103.1

A field-erected refrigerant piping system is ready for its pressure test. Which test medium does the IMC allow?

Answer: Oxygen-free nitrogen

IMC 2024 Section 1110.3 lists the allowed field pressure test media: oxygen-free nitrogen, helium, argon, or premixed nonflammable oxygen-free nitrogen with a hydrogen or helium tracer. Section 1110.3.1 prohibits oxygen, air, refrigerants other than those listed, and combustible gases. Oxygen under pressure with oil residue can explode, and air brings in moisture.

Reference: 2024 International Mechanical Code (as adopted in Utah), Sections 1110.3 and 1110.3.1

A mechanical floor plan is drawn at 1/4" = 1'-0". A supply trunk measures 6-1/2 inches on the drawing. What is its actual length?

Answer: 26 feet

At 1/4" = 1'-0", each drawing inch equals 4 feet. So 6.5 in × 4 ft/in = 26 feet. A common mistake is to use the 1/8" scale factor (8 ft per inch) or to drop the half inch: 6 × 4 = 24 feet. Always check the scale in the title block, or on the individual detail, before measuring.

Reference: Modern Refrigeration and Air Conditioning, 22nd ed., Blueprint reading: drawing scales

Using the standard-air sensible heat equation Q = 1.08 × cfm × ΔT, what is the sensible heat delivered by 1,200 cfm with a 20°F temperature difference across the coil?

Answer: 25,920 Btu/h

Q = 1.08 × 1,200 × 20 = 25,920 Btu/h. Leaving out the 1.08 factor gives 24,000. Using the latent factor 0.68 by mistake gives 16,320. The 21,600 figure comes from using 0.90, a factor sometimes used for high altitude. At Utah elevations, the air density factor really is lower than the standard 1.08, so check which value the problem or your design procedure calls for.

Reference: Modern Refrigeration and Air Conditioning, 22nd ed., Psychrometrics: sensible heat (Q = 1.08 × cfm × ΔT)