CO Boiler Installation Contractor Exam
Questions And Correct Answers
(Verified Answers) Plus Rationale2026
Q&A| Instant Download Pdf
1. What is the primary purpose of a boiler expansion tank in a hydronic
heating system?
A. Improve combustion efficiency
B. Collect sediment
C. Absorb thermal expansion of water
D. Reduce stack temperature
The expansion tank accommodates increased water volume as it heats,
preventing overpressure conditions.
2. Which code primarily governs boiler installation requirements in
Colorado?
A. NEC
B. AWWA
C. ASME Boiler and Pressure Vessel Code
D. OSHA 1910
Colorado adopts ASME standards as the basis for boiler fabrication and
installation compliance.
3. Low-water cutoff devices are required on which type of boiler?
A. Only condensing boilers
B. Only residential units
C. All steam boilers
,D. Gas-fired water heaters
Steam boilers risk overheating and explosion if water levels drop, requiring
automatic LWCO protection.
4. A boiler room must have how many air openings if using outdoor
combustion air?
A. One
B. Two
C. Three
D. Four
Two openings—high and low—ensure adequate combustion and
ventilation airflow.
5. The minimum clearance for service access around a boiler is typically:
A. 6 inches
B. 12 inches
C. 18 inches
D. Manufacturer-specified
Manufacturer installation manuals supersede generic distances for
equipment safety and warranty.
6. What is the function of a barometric draft regulator?
A. Increase gas pressure
B. Stabilize chimney draft
C. Filter combustion air
D. Shut off gas during flame failure
It modulates airflow to keep draft within proper limits for safe combustion.
7. A pressure relief valve must discharge to:
A. A chimney
B. A safe, visible location
C. A sewer line
D. Outdoors only
It must discharge where operators can observe a malfunction and prevent
hazards.
, 8. What is the typical maximum pressure rating for residential hot water
boilers?
A. 15 psi
B. 20 psi
C. 30 psi
D. 50 psi
Most residential relief valves open at 30 psi to protect components.
9. What is required before firing a newly installed boiler?
A. Draft test only
B. Pre-startup inspection
C. Water treatment
D. Cleaning the burner only
A full inspection ensures correct installation, venting, pressure controls,
and safety devices.
10. Which fuel system component reduces incoming gas pressure before
entering the boiler?
A. Flow meter
B. Gas regulator
C. Manometer
D. Orifice plate
Regulators ensure burner systems receive stable, correct pressure.
11. A hydronic system air separator is located at the:
A. Lowest point
B. Hottest point
C. Coldest point
D. Gas supply riser
Air removal is most effective where water temperature is highest and
solubility lowest.
12. What is stack temperature primarily an indicator of?
Questions And Correct Answers
(Verified Answers) Plus Rationale2026
Q&A| Instant Download Pdf
1. What is the primary purpose of a boiler expansion tank in a hydronic
heating system?
A. Improve combustion efficiency
B. Collect sediment
C. Absorb thermal expansion of water
D. Reduce stack temperature
The expansion tank accommodates increased water volume as it heats,
preventing overpressure conditions.
2. Which code primarily governs boiler installation requirements in
Colorado?
A. NEC
B. AWWA
C. ASME Boiler and Pressure Vessel Code
D. OSHA 1910
Colorado adopts ASME standards as the basis for boiler fabrication and
installation compliance.
3. Low-water cutoff devices are required on which type of boiler?
A. Only condensing boilers
B. Only residential units
C. All steam boilers
,D. Gas-fired water heaters
Steam boilers risk overheating and explosion if water levels drop, requiring
automatic LWCO protection.
4. A boiler room must have how many air openings if using outdoor
combustion air?
A. One
B. Two
C. Three
D. Four
Two openings—high and low—ensure adequate combustion and
ventilation airflow.
5. The minimum clearance for service access around a boiler is typically:
A. 6 inches
B. 12 inches
C. 18 inches
D. Manufacturer-specified
Manufacturer installation manuals supersede generic distances for
equipment safety and warranty.
6. What is the function of a barometric draft regulator?
A. Increase gas pressure
B. Stabilize chimney draft
C. Filter combustion air
D. Shut off gas during flame failure
It modulates airflow to keep draft within proper limits for safe combustion.
7. A pressure relief valve must discharge to:
A. A chimney
B. A safe, visible location
C. A sewer line
D. Outdoors only
It must discharge where operators can observe a malfunction and prevent
hazards.
, 8. What is the typical maximum pressure rating for residential hot water
boilers?
A. 15 psi
B. 20 psi
C. 30 psi
D. 50 psi
Most residential relief valves open at 30 psi to protect components.
9. What is required before firing a newly installed boiler?
A. Draft test only
B. Pre-startup inspection
C. Water treatment
D. Cleaning the burner only
A full inspection ensures correct installation, venting, pressure controls,
and safety devices.
10. Which fuel system component reduces incoming gas pressure before
entering the boiler?
A. Flow meter
B. Gas regulator
C. Manometer
D. Orifice plate
Regulators ensure burner systems receive stable, correct pressure.
11. A hydronic system air separator is located at the:
A. Lowest point
B. Hottest point
C. Coldest point
D. Gas supply riser
Air removal is most effective where water temperature is highest and
solubility lowest.
12. What is stack temperature primarily an indicator of?
