Have the relevant third parties provided their consent? Do threats to compliance impair your independence? Are threats to compliance with the code at an acceptable level?
Answer:
C or D
Explanation:
When we say a furnace is “sealed combustion,” it means it draws on air from outside the house to use for burning fuel (i.e. combusting fuel). ... It's closed-off and draws air through a plastic PVC pipe that connects it to the outside. A second pipe attached to the combustion chamber sends out the exhaust
