Johnson Controls ZY Series, Installation Manual

Page: 118 / 144

Indoor Air Quality AQ
Indoor Air Quality (indoor sensor input): Terminal
AQ accepts a +2 to +10 VDC signal with respect to
the (AQ1) terminal. When the signal is below it's set
point, the actuator is allowed to modulate normally
in accordance with the enthalpy and mixed air
sensor inputs. When the AQ signal exceeds it's set
point setting and there is no call for free cooling, the
actuator is proportionately modulated from the 2
to 10 VDC signal, with 2 VDC corresponding to full
closed and 10 VDC corresponding to full open. When
there is no call for free cooling, the damper position
is limited by the IAQ Max damper position setting.
When the signal exceeds it's set point (Demand
Control Ventilation Set Point) setting and there is a
call for free cooling, the actuator modulates from
the minimum position to the full open position
based on the highest call from either the mixed air
sensor input or the AQ voltage input.
•
Optional CO
2
Space Sensor Kit Part #
2AQ04700524B
•
Optional CO
2
Sensor Kit Part # 2AQ04700624C
Figure 32: Ignition Control Board
Gas Heating Operation
1. Heating stages are controlled by the W1
through W2 thermostat inputs. A W1 or W2
input energizes a H1 or H1/H2 output.
2. When the pre-ignition process is complete the
ignition module energizes the gas valve and
provides a 24 V input to the MV terminal on
the UCB.
3. The FAN ON HEAT DELAY timer starts as soon
as 24 V is present on MV terminal. When the
timer expires the FAN output for the indoor
fan operation energizes. If 24 V is not received
on the MV terminal within 6 minutes, an
alarm appears and the fan output energizes
immediately and remains On until the alarm
clears.
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 ZY SERIES 3 - 10 ton 60 Hertz R-410A 118
Johnson Controls Ducted Systems