What does a "lockout" mean in an HVAC control sequence?

What does a "lockout" mean in an HVAC control sequence?

• A. A reminder to service equipment
• B. A method to secure building access
• C. A safety or fault condition that prevents equipment from starting until the fault is cleared
• D. An automatic restart after a fault

Answer: (C)

Lockout means a fault or safety condition has occurred that blocks the equipment from starting or restarting. The control intentionally prevents operation until the issue is resolved, protecting the system from damage or unsafe operation. Once the fault is cleared (and sometimes after a manual or automatic reset, depending on the system), normal operation can resume. This is why the description of a safety or fault condition preventing startup until cleared is the best match.

Lockout means a fault or safety condition has occurred that blocks the equipment from starting or restarting. The control intentionally prevents operation until the issue is resolved, protecting the system from damage or unsafe operation. Once the fault is cleared (and sometimes after a manual or automatic reset, depending on the system), normal operation can resume. This is why the description of a safety or fault condition preventing startup until cleared is the best match.