A furnace is installed in a confined room after envelope air sealing. What must be verified before startup?
- Approved combustion and ventilation air
- BDoor undercut alone in every case
- CA carbon-monoxide alarm instead of combustion air
- DHigher manifold pressure
Why A is correct
Tightening the building can reduce available air and create depressurization or spillage. Required openings or engineered methods must match appliance input and space conditions.