New Mexico CID MM-4 Heat, Cooling and Process Pipe Examination

How many years of experience does 14.6.6.11 NMAC require for the MM-4 heating, cooling, and process piping classification?

• ATwo years
• BThree years
• CFour years
• DSix years

Which work is inside the MM-4 scope in 14.6.6.11 NMAC?

• APotable-water plumbing fixtures and building drains
• BSteam and hot-water piping of any temperature or pressure, chilled water, condensing wate…
• CNatural-gas fitting as a stand-alone trade, including LP-gas systems
• DLine-voltage motor wiring above 24 volts

Which official PSI MM-4 examination description matches bulletin 865 updated 4/3/2026?

• A90 scored questions, 75 percent (68 points), 235 minutes, USD 68.88, open-book CBT, Engli…
• B50 scored questions, 70 percent, 120 minutes, USD 50, closed-book paper
• C100 scored questions, 80 percent, 4 hours, USD 100, Spanish only
• D75 scored questions, 65 percent, 180 minutes, no fee, oral exam

Which reference is listed as not allowed in the PSI MM-4 exam center?

• AUMC 2021
• BNMAC 14.9.4 (2005) New Mexico Boiler Rules
• CNFPA 13 (2007)
• DNFPA 31 and Low Pressure Boilers

Which model code does 14.9.2 NMAC adopt, as amended, as the technical base of the New Mexico Mechanical Code?

• A2021 International Mechanical Code
• B2021 Uniform Mechanical Code
• C2021 Uniform Plumbing Code
• D2018 International Fuel Gas Code

Under 14.9.2.10 NMAC, who is the authority having jurisdiction for the New Mexico Mechanical Code as the statewide minimum?

• AThe serving gas utility
• BIAPMO
• CThe CID and the mechanical-plumbing trade bureau chief
• DThe local fire marshal only

Which UMC chapter, adopted without a New Mexico text change in 14.9.2.22 NMAC, governs process piping?

• AChapter 4, Ventilation Air
• BChapter 6, Duct Systems
• CChapter 13, Fuel Gas Piping
• DChapter 14, Process Piping

Which UMC chapter, adopted with only the 1205.2 test amendment in 14.9.2.20 NMAC, governs hydronic piping?

• AChapter 11, Refrigeration
• BChapter 12, Hydronics
• CChapter 15, Solar Energy Systems
• DChapter 8, Chimneys and Vents

How does 14.9.2.11 NMAC change UMC 305.5 drainage-pan coverage?

• AIt deletes drainage pans entirely
• BIt applies the pan rule only to electric water heaters
• CIt adds hot-water-heating boilers after each use of the term water heater
• DIt requires a pan only when the boiler is outdoors

A closed hydronic loop will operate at 40 psi. What minimum pressure test does 14.9.2.20 NMAC require in place of the first sentence of UMC 1205.2?

• AA hydrostatic or air test of not less than 60 psi
• BA 10 psi air test for 15 minutes
• COperating pressure only, with no multiplier
• DA 200 psi hydrostatic test on every residential loop

A hydronic heating circuit delivers 32 gpm of water with a 20°F temperature drop. Using Q = 500 × gpm × ΔT, what is the heat output?

• A160,000 Btu/h
• B320,000 Btu/h
• C640,000 Btu/h
• D32,000 Btu/h

A 40-ton water chiller is designed for a 10°F chilled-water rise. What evaporator flow is required using 2.4 gpm per ton at 10°F, or Q = 500 × gpm × ΔT?

• A40 gpm
• B80 gpm
• C96 gpm
• D120 gpm

A 150 ft run of steel pipe has an inside diameter of 4.026 in. Using gallons per foot = ID² × 0.0408, what is the water volume of the pipe?

• A49.6 gallons
• B66.1 gallons
• C99.2 gallons
• D150 gallons

A closed hydronic system holds 180 gallons. Water is heated from 40°F to 200°F. Using the stated specific volumes 0.01602 ft³/lb at 40°F and 0.01663 ft³/lb at 200°F, how much expansion volume must the tank accept, ignoring dissolved-air and tank acceptance factors?

• A3.4 gallons
• B6.9 gallons
• C10.8 gallons
• D18.0 gallons

A 30 psi hydronic fill pressure equals how many feet of water column? Use 1 psi = 2.31 ft w.c.

• A13.0 ft
• B30.0 ft
• C69.3 ft
• D138.6 ft

How does 14.9.2.11 NMAC change UMC 305.1 for appliances in garages?

• AIt deletes the entire garage-elevation rule
• BIt deletes the phrase “unless listed as a flammable vapor ignition resistant,” so the ele…
• CIt allows any ignition source on the garage floor if the door is weatherstripped
• DIt applies only to oil burners

Which return-air sources does 14.9.2.11 NMAC substitute into UMC 311.3 as prohibited?

• AAny room with a window
• BA closet, bathroom, laundry room, toilet room, or kitchen, or a location that will pick u…
• CAn outdoor louver more than 10 feet above grade
• DA mechanical room that contains only hydronic pumps

What does 14.9.2.11 NMAC require in place of UMC 314.0 balancing?

• ANo balancing is required in New Mexico
• BOnly air systems shall be balanced; hydronic systems are exempt
• CHeating, ventilating, and air-conditioning systems, including hydronic systems, shall be…
• DBalancing is required only on systems larger than 100 tons

A cooling tower enters at 95°F, leaves at 85°F, and the entering wet bulb is 78°F. What are the range and approach?

• ARange 17°F, approach 7°F
• BRange 10°F, approach 7°F
• CRange 7°F, approach 10°F
• DRange 10°F, approach 17°F

A pressure-enthalpy chart for the job gives evaporator outlet enthalpy h1 = 128 Btu/lb and liquid enthalpy entering the expansion device h4 = 33 Btu/lb. What is the refrigerating effect per pound of refrigerant?

• A33 Btu/lb
• B95 Btu/lb
• C128 Btu/lb
• D161 Btu/lb

Using the same chart values (refrigerating effect 95 Btu/lb), a chiller circulates 200 lb/min of refrigerant. What is the cooling capacity in tons? 1 ton = 200 Btu/min.

• A47.5 tons
• B95 tons
• C190 tons
• D12 tons

A carbon-steel process line is 80 ft long between anchors and is heated from 40°F to 180°F. Using α = 6.5 × 10⁻⁶ in/in·°F, what is the unrestrained expansion?

• A0.44 in
• B0.87 in
• C1.56 in
• D2.08 in

A 45-degree offset must clear 18 in. What is the center-to-center travel of the offset pipe? Travel = offset × 1.414.

• A12.7 in
• B18.0 in
• C25.5 in
• D36.0 in

On a plan drawn at 1/4 in. = 1 ft-0 in., a hydronic main measures 6-3/4 in. on the sheet. What is the actual pipe length?

• A13.5 ft
• B18 ft
• C27 ft
• D54 ft

How does 14.9.2.13 NMAC change UMC 511.3 makeup-air rules for exhaust systems?

• AWindows and doors may be used as the makeup-air path
• BWindows and doors shall not be used for makeup air; the exhaust and makeup-air systems sh…
• CMakeup air is never required in New Mexico
• DOnly gravity louvers, with no interlock, are accepted

Which statement about UMC Chapter 11 refrigeration, adopted by 14.9.2.19 NMAC, is correct for MM-4 water-chiller work?

• ARefrigerant piping may be run in a public exit stairway if it is insulated
• BRefrigeration systems are unregulated in New Mexico
• CChapter 11 governs refrigerant piping, occupancy classification, machinery rooms, and pre…
• DOnly ammonia systems are covered; HFC chillers are exempt

A 200 ft loop of 2-inch pipe (ID 2.067 in.) plus a 40-gallon boiler and an 8-gallon air separator must be filled. What is the nearest system water volume? Use gal/ft = ID² × 0.0408.

• A34.8 gallons
• B48.0 gallons
• C82.8 gallons
• D120.0 gallons

A 25 percent propylene-glycol loop uses a heat-capacity factor of 479 instead of 500. The circuit is 40 gpm at a 15°F ΔT. What is the heat transfer?

• A287,400 Btu/h
• B300,000 Btu/h
• C320,000 Btu/h
• D479,000 Btu/h

Saturated steam at 0 psig is condensed at 970 Btu/lb. A process heat exchanger condenses 350 lb/h. What is the heat release, and about how many gallons of condensate leave per hour at 8.34 lb/gal?

• A339,500 Btu/h and 42 gal/h
• B970,000 Btu/h and 350 gal/h
• C33,950 Btu/h and 4.2 gal/h
• D3,395,000 Btu/h and 420 gal/h

Which MM-4 work item is inside 14.6.6.11 NMAC but is not a full MS-12 or MS-14 specialty by itself?

• AWater-based fire-protection sprinkler systems and dry-chemical fire-protection systems, a…
• BOnly kitchen wet-chemical hood systems as a stand-alone specialty
• COnly underground public water mains in the street right-of-way
• DOnly electrical fire-alarm programming above 24 volts

A 60-foot-tall hydronic riser is filled from the basement. What minimum static fill pressure is needed at the basement gauge just to push water to the top, before any cushion? Use 1 psi = 2.31 ft.

• A12 psi
• B26 psi
• C60 psi
• D139 psi

14.9.2.11 NMAC amends UMC 304.3.1 roof-access rules by adding an exception after “in height.” Which occupancy is excepted?

• AH-2 high-hazard
• BA-2 assembly
• CR-3 occupancies
• DI-2 hospitals

Per 14.9.4.7 NMAC, a high-pressure steam boiler is a boiler in which steam or other vapor is generated at pressures exceeding what value?

• A5 psi
• B15 psi
• C30 psi
• D160 psi

Per 14.9.4.7 NMAC, a high-temperature water boiler is used for heating water or liquid to a pressure exceeding 160 psi or to a temperature exceeding what?

• A180°F
• B200°F
• C212°F
• D250°F

What inspection frequency does 14.9.4.25 NMAC require for high-pressure boilers?

• AExternal only, every 60 months
• BInternal annually, with a certificate possible from an external if an internal follows wi…
• CNo inspection if the boiler is listed
• DInternal only when the owner requests it

What inspection frequency does 14.9.4.25 NMAC require for low-pressure steam boilers and low-pressure hot-water heating boilers?

• AExternal and internal every 24 months
• BInternal every 30 days
• CExternal only, once in the life of the boiler
• DThe same annual internal as a high-pressure boiler, with no 24-month option

Under 14.9.4.7 NMAC, what does a red inspection tag mean?

• AThe boiler passed and may operate until the next certificate date
• BOnly a missing nameplate, with no safety concern
• CMajor leaks, badly deteriorated refractory that could overheat the unit, a safety or safe…
• DThe boiler is new and has not yet been fired

A lap-seam crack is found along a longitudinal riveted joint. What does 14.9.4.16 NMAC require?

• AWeld the crack and return the boiler to service the same day
• BPeen the crack and raise the MAWP
• CRemove the boiler from service; repairs are prohibited
• DIgnore it if the boiler is low pressure

A hydrostatic test is required after a boiler repair. 14.9.4.32 NMAC says the required test pressure may be no more than the MAWP, and the test pressure shall not be exceeded by more than what percent?

• A2 percent
• B6 percent
• C10 percent
• D50 percent

A 150 psi MAWP boiler is being hydrostatically tested after a repair. If the inspector sets the required test at MAWP, what is the highest pressure 14.9.4.32 NMAC allows you to reach?

• A150 psi
• B153 psi
• C159 psi
• D225 psi

Hydronic piping and fittings under UMC Chapter 12, as adopted by 14.9.2.20 NMAC, must be:

• AAny leftover gas CSST on the truck
• BListed and rated for the fluid, temperature, and pressure of the hydronic system
• CUnlisted thin-wall electrical conduit
• DRefrigerant ACR tubing, because both are closed loops

A closed hydronic heating system is placed in service with no expansion tank and no boiler pressure-relief valve. What do UMC Chapters 10 and 12 require?

• ANothing; modern boilers do not need relief or expansion control
• BOnly a larger circulator
• CAn expansion tank or other approved expansion control, plus a listed pressure-relief valv…
• DA fuel-gas sediment trap on the water piping

Which UMC chapter, adopted without change by 14.9.2.18 NMAC, governs boilers and pressure vessels?

• AChapter 5, Exhaust Systems
• BChapter 9, Installation of Specific Appliances
• CChapter 10, Boilers and Pressure Vessels
• DChapter 16, Stationary Power Plants

Which UMC chapter, adopted by 14.9.2.23 NMAC, covers the high-pressure and process solar-thermal systems named in the MM-4 scope?

• AChapter 4, Ventilation Air
• BChapter 6, Duct Systems
• CChapter 13, Fuel Gas Piping
• DChapter 15, Solar Energy Systems

A steam main should be pitched so condensate runs to the drip legs. What is the usual trade pitch toward the drip, as used in IPT pipe-trades practice?

• ALevel, with no pitch
• B1/4 in. per 10 ft toward the drip or trap
• C2 in. per foot uphill toward the far end
• D1 in. per foot downhill with no traps

What is the function of a steam trap on a process heat exchanger?

• ATo hold steam in the coil until the coil is waterlogged
• BTo discharge condensate and noncondensable gases while holding back live steam
• CTo raise steam pressure above the boiler MAWP
• DTo replace the boiler safety valve

Which steam trap type uses a float to discharge condensate and a thermostatic element to vent air, and is common on heat exchangers with widely varying loads?

• AThermodynamic disc trap only
• BOrifice plate with no moving parts and no air vent
• CFloat-and-thermostatic (F&T) trap
• DA gate valve cracked open as a trap