Gas Appliances and Equipment Installation
Domain 5 examines appliance installation: clearances, supports, gas connections, venting, condensate, and location. The exam tests whether you can read a rating plate and manual and apply code requirements to real rooms.
Installation rules
Install only appliances certified for the gas and application. Maintain clearances to combustibles from the rating plate and manual; the greater requirement governs. Provide access for service and combustion air. Level and support the appliance. Connect with an approved connector, shutoff valve, and sediment trap. Follow venting instructions exactly.
Special locations
Garage heaters: ignition sources and burners must be at least 18 in (450 mm) above the floor unless the appliance is listed for lower installation, and protect against vehicle impact. Closets and alcoves need louvered doors or openings sized for combustion air. Furnaces in crawlspaces need a stable base and access.
Worked example
A customer wants a unit heater in a garage. The manual permits installation with burners 18 in above floor. You set the heater so the burner and ignition source are 18 in up, maintain the listed rear clearance, and install a bollard to protect it from the car. You verify the flue termination clears the roof and wall per code.
Traps
- Using the code clearance when the manual requires more.
- Installing a natural gas appliance without converting for propane.
- Blocking the relief opening of a draft hood.
- Ignoring condensate disposal on a condensing appliance.
- Leaving an appliance connector passing through a wall or ceiling.