York International ZQ Series Installation Manual page 71

4. When the thermostat heat inputs are lost and
the 120 second Minimum Heat Run Timers
have expired, heating outputs stage off. The
FAN OFF HEAT DELAY timer starts when 24 V
is removed from the MV terminal. When the
timer expires, the FAN output for the indoor
fan operation de-energizes.
Note: If 24 V is lost on the MV terminal
during the same heat cycle, an alarm
appears and the fan output energizes
and remains On until 24 V is present
again on the MV terminal.
Note: If 24 V is present on the MV
terminal without a call for heat, an alarm
appears and the fan output energizes.
If this condition occurs for 6 minutes an
alarm appears, and remains, until the
alarm condition is cleared.
5. At any time, if 24 V is lost on the LIMIT
terminal, the FAN output for indoor fan
operation is energized. If 24 V is lost on
the LIMIT input 3 times in 1 hour, an alarm
appears and the FAN output is energized. The
heating H1 and H2 outputs are de-energized
until the alarm is cleared.
INSTALLATION MANUAL ZQ SERIES 3 - 5 ton 60 Hertz R-410A
Johnson Controls Ducted Systems
71