HVAC Procedure and Performance Guide

TASK: Install gas combination heating and domestic hot water system

Training for this procedure can be found in these courses:

                         133 – HVACR Gas Heat l   and  191 – Hydronics l


Gas hot water heating system must be installed according to manufacturer’s specifications, job specifications and codes.  Equipment and piping must be sized to meet structure’s heating requirements and must provide domestic hot water requirements.  It must meet code requirements.  Applicable safety procedures must be followed.


    1. Review job order, manufacturer’s specifications, job specifications and codes.
    2. Collect tools, equipment and materials.
    3. Put on safety and protective equipment and apparel.
    4. Determine location and install hot water heater and fan-coil unit.
    5. Prepare structure openings.
    6. Run vent pipe.
    7. Determine size of piping and install.
    8. Connect cold water supply.
    9. Make electrical connections.
    10. Make duct connections to air-handling coil.
    11. Make control connections.
    12. Install filter and check for leaks.
    13. Install insulation.
    14. Verify that unit is installed according to manufacturer’s specifications and local and national codes.
    15. Request building inspector to inspect installation.
    16. Contact gas utility company and request that gas be turned on.
    17. Place system in operation.
      1. Make necessary adjustments.
      2. Set heat anticipator on thermostat.
      3. Check airflow across coil.
    18. If equipment does not operate to specifications, troubleshoot and make required adjustments and repairs.
    19. Make final inspection of work.
    20. Leave equipment in required operating status.
    21. Remove safety and protective equipment and apparel.
    22. Gather tools, equipment and leftover materials, and leave work site clean.
    23. Review operation of equipment with owner.