NEW MEXICO MM-98 MECHANICAL CONTRACTOR
EXAM 100 COMPLETE QUESTIONS AND ANSWERS |
CONTENT WELL ORGANIZED 2026/2027 NEWTEST
UPDATE | 100 % RATED AND VERIFIED SOLUTIONS
| GET AN A+ NEW VERSION!!! INSTANT PDF
MOST TESTED TOPICS
HVAC SYSTEMS DESIGN AND INSTALLATION
PLUMBING SYSTEMS AND FIXTURES
NATURAL GAS PIPING AND SAFETY
PROCESS PIPING AND MATERIALS
VENTING AND COMBUSTION AIR
CODES AND REGULATIONS
LOAD CALCULATIONS AND SIZING
TROUBLESHOOTING AND SAFETY PRACTICES
1. A contractor installs a gas furnace in a confined space. What is the primary
requirement for combustion air?
A. Air from attic only
B. Air from outdoors or properly sized openings
C. Air from return ducts
D. No additional air needed
Answer: B
Confined spaces require adequate combustion air, typically from outdoors
or properly sized openings to prevent incomplete combustion and carbon
monoxide buildup.
2. A water heater T&P relief valve discharge pipe must terminate:
A. Above roof
B. Into sewer line
C. Within 6 inches of floor
, D. Into vent stack
Answer: C
The discharge must terminate near the floor to prevent scalding and allow
safe drainage.
3. What is the main purpose of a P-trap in plumbing?
A. Increase pressure
B. Prevent backflow
C. Block sewer gases
D. Improve flow rate
Answer: C
P-traps retain water to block sewer gases from entering occupied spaces.
4. A duct system is undersized. What is the most likely result?
A. Increased airflow
B. Reduced static pressure
C. Poor airflow and system inefficiency
D. Lower energy use
Answer: C
Undersized ducts restrict airflow, reducing efficiency and comfort.
5. Which gas piping material is commonly prohibited underground without
protection?
A. Black steel
B. Copper
C. PVC
D. CSST
Answer: B
Copper can react with certain soils and gases unless properly protected.
6. A boiler short cycles frequently. What is the likely issue?
A. Oversized unit
B. Low voltage
C. High insulation
D. Large piping
, Answer: A
Oversized boilers heat too quickly and shut off frequently, reducing
efficiency.
7. What is the purpose of a backflow preventer?
A. Increase flow
B. Prevent contamination
C. Reduce pressure
D. Store water
Answer: B
Backflow preventers stop contaminated water from reversing into clean
supply.
8. In HVAC, what does SEER measure?
A. Airflow
B. Efficiency
C. Pressure
D. Voltage
Answer: B
SEER indicates cooling efficiency over a season.
9. A gas leak test is typically performed using:
A. Oxygen
B. Nitrogen or air
C. Helium
D. Carbon dioxide
Answer: B
Air or inert gas like nitrogen is used to safely test for leaks.
10.What is the function of a heat exchanger?
A. Mix air and gas
B. Transfer heat without mixing fluids
C. Increase pressure
D. Cool refrigerant
EXAM 100 COMPLETE QUESTIONS AND ANSWERS |
CONTENT WELL ORGANIZED 2026/2027 NEWTEST
UPDATE | 100 % RATED AND VERIFIED SOLUTIONS
| GET AN A+ NEW VERSION!!! INSTANT PDF
MOST TESTED TOPICS
HVAC SYSTEMS DESIGN AND INSTALLATION
PLUMBING SYSTEMS AND FIXTURES
NATURAL GAS PIPING AND SAFETY
PROCESS PIPING AND MATERIALS
VENTING AND COMBUSTION AIR
CODES AND REGULATIONS
LOAD CALCULATIONS AND SIZING
TROUBLESHOOTING AND SAFETY PRACTICES
1. A contractor installs a gas furnace in a confined space. What is the primary
requirement for combustion air?
A. Air from attic only
B. Air from outdoors or properly sized openings
C. Air from return ducts
D. No additional air needed
Answer: B
Confined spaces require adequate combustion air, typically from outdoors
or properly sized openings to prevent incomplete combustion and carbon
monoxide buildup.
2. A water heater T&P relief valve discharge pipe must terminate:
A. Above roof
B. Into sewer line
C. Within 6 inches of floor
, D. Into vent stack
Answer: C
The discharge must terminate near the floor to prevent scalding and allow
safe drainage.
3. What is the main purpose of a P-trap in plumbing?
A. Increase pressure
B. Prevent backflow
C. Block sewer gases
D. Improve flow rate
Answer: C
P-traps retain water to block sewer gases from entering occupied spaces.
4. A duct system is undersized. What is the most likely result?
A. Increased airflow
B. Reduced static pressure
C. Poor airflow and system inefficiency
D. Lower energy use
Answer: C
Undersized ducts restrict airflow, reducing efficiency and comfort.
5. Which gas piping material is commonly prohibited underground without
protection?
A. Black steel
B. Copper
C. PVC
D. CSST
Answer: B
Copper can react with certain soils and gases unless properly protected.
6. A boiler short cycles frequently. What is the likely issue?
A. Oversized unit
B. Low voltage
C. High insulation
D. Large piping
, Answer: A
Oversized boilers heat too quickly and shut off frequently, reducing
efficiency.
7. What is the purpose of a backflow preventer?
A. Increase flow
B. Prevent contamination
C. Reduce pressure
D. Store water
Answer: B
Backflow preventers stop contaminated water from reversing into clean
supply.
8. In HVAC, what does SEER measure?
A. Airflow
B. Efficiency
C. Pressure
D. Voltage
Answer: B
SEER indicates cooling efficiency over a season.
9. A gas leak test is typically performed using:
A. Oxygen
B. Nitrogen or air
C. Helium
D. Carbon dioxide
Answer: B
Air or inert gas like nitrogen is used to safely test for leaks.
10.What is the function of a heat exchanger?
A. Mix air and gas
B. Transfer heat without mixing fluids
C. Increase pressure
D. Cool refrigerant
