A commissioning test shows most supply air going directly into a nearby return while the occupied zone receives little circulation. What should be investigated first?
- AWhether the wall paint matches the diffuser.
- BWhether the room number is on the thermostat.
- Supply throw, diffuser orientation and return placement.
- DWhether all registers are spaced at exactly 35 feet.
Where to look it up
Explicit exercise assumptions; not a universal code requirement.
Why C is correct
The observed path suggests air-distribution short-circuiting. Investigate the actual pattern rather than inventing a universal register-spacing limit. This is a diagnostic scenario, not a code clearance rule.