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JOHNSON CONTROLS
FORM 100.50-NOM6 (1207)
5
The Simplicity Control monitors the operation of the
supply fan by checking the status of a digital input from
an air proving switch. After 90 seconds of operation,
the Simplicity Control looks for a high state (24-volt
input) from the air proving switch circuit at the “APS”
connections at the P11 connector on the Simplicity
control board. If this input does not go to the high state
in this time frame the Simplicity Control will set an Air
Pressure Switch Unit Lockout, Alarm Code 24 and turn
off all outputs.
The Simplicity Control will retry the fan output every
30 minutes for three retries. If after three retires it still
cannot qualify the fan, it will continue the alarm and
lock out all heating and cooling operation. If the switch
closes during one of the restarts, the control will resume
normal operation and clear the active alarm.
An Air Pressure Switch Unit Lockout will also be
declared if the input goes low, for 2 seconds, during
normal supply fan operation.
The Simplicity Control also monitors the supply fan
operation in the off cycle. 90 seconds after the digital
output from the Simplicity control supply fan circuit
goes low (0 volts) the Simplicity Control checks the
status of the digital input from the air proving switch
circuit. If the state of the circuit remains high (24-volts)
the Simplicity Control will set an Air Pressure Switch
stuck closed, Alarm Code 25. As soon as the pressure
switch opens, the Simplicity Control will resume normal
operation.
On a call for supply fan operation, the Simplicity
Control sends a 24 VAC signal from the FAN terminal
of the P13 connector to the supply fan relay.
Variable Air Volume (VAV)
The supply will be energized when:
• The supply fan has been off for 10 seconds and
anyone of the following occurs:
– The unit is in the occupied mode.
– The unit is in the Unoccupied heating or
cooling mode and there is a 24 volt input to
terminal Y1, Y2, Y3, Y4, W1, W2, or W3 of
the Simplicity control terminal board and the
“COOL, FAN ON DELAY” or “HEAT, FAN
ON DELAY” have timed out. The “HEAT,
FAN ON DELAY” timer does not start until
the control receives a signal that the gas valve
is energized.
The supply fan will be de-energized when:
• The supply fan has been on for 30 seconds and
anyone of the following occurs:
– Any time the unit goes unoccupied and there
is no call for cooling or heating operation.
– Any time the 24 volt input to terminal Y1,
Y2, Y3, Y4, W1, W2, or W3 of the Simplic-
ity control terminal board is removed and the
“COOL, FAN OFF DELAY” or “HEAT, FAN
OFF DELAY” have timed out. The “HEAT,
FAN OFF DELAY” timer does not start until
the control receives a signal that the gas valve
is de-energized.
The Simplicity Control monitors the operation of the
supply fan by checking the status of a digital input from
an air proving switch. After 90 seconds of operation,
the Simplicity Control looks for a high state (24-volt
input) from the air proving switch circuit at the “APS”
connections at the P11 connector on the Simplicity
control board. If this input does not go to the high state
in this time frame the Simplicity Control will set an Air
Pressure Switch Unit Lockout, Alarm Code 24 and turn
off all outputs. The Simplicity Control also monitors
the duct static pressure input during this time. If the
duct static pressure is above 0.05” WC the control will
generate a Air Pressure Switch Unit Lockout, Alarm
Code 24 but continue to operate.
The Simplicity Control will retry the fan output every
30 minutes for three retries. If after three retires it still
cannot qualify the fan, it will continue the alarm and
lock out all heating and cooling operation. If the switch
closes during one of the restarts, the control will resume
normal operation and clear the active alarm.
An Air Pressure Switch Unit Lockout will also be
declared if the input goes low, for 2 seconds, during
normal supply fan operation.
The Simplicity Control also monitors the supply fan
operation in the off cycle. 90 seconds after the digital
output from the Simplicity Control supply fan circuit
goes low (0 volts) the Simplicity Control checks the
status of the digital input from the air proving switch
circuit. If the state of the circuit remains high (24-volts)
the Simplicity Control will set an Air Pressure Switch
stuck closed, Alarm Code 25. As soon as the pressure
switch opens the Simplicity Control will resume normal
operation.