Why do I get an Error about Fan Control = Cycling?

You are probably seeing a message such as:

 “airsystem ‘xyz” has fan control = ‘cycling’, but this system is defined to provide ‘forced’ ventilation for control zone ‘zone A’ evaluating rule: set checkcode airsys:fanctrl (75:’hvacsecondary-systemcontrols.rule line 330)

This is a message from the CEC CBECC side and basically indicates you have a Zone in which the HVAC system will be providing the ventilation.  However, in the Central System Library, at the Controls Tab, you have indicated the fans do not run continuously.

The fans must run continuously to provide ventilation if the ventilation comes from the HVAC system.  You should change this setting to Continuous.

Note that the ventilation setting is done at the Zone level of the tree, Mechanical tab.  In Hghrise Residential/ Hotel Motel occupancies it is acceptable to use Natural Ventilation and thus this could be set to “Natural”, with the fans set to “Intermittent” but not in commercial occupancies.

Categories: 9. Nonresidential Title 24 Performance

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