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The following section is to be used in conjunction with Fig. 3 on
page 45. To help determine why the unit controls are in a certain
mode, the programming logic is provided below. The software
will proceed, step by step, until a mode is reached. If an "If" state-
ment is true, then that mode will be entered. The "Else" statement
refers to other possible choices.
If the System Mode is OFF:
{
If the fire shut down input (Inputs
is in "alarm":
HVAC mode:
Else
HVAC mode:
}
Else If: The rooftop is not in "factory test" and a fire
smoke-control mode is "alarming":
{
If the pressurization input (Inputs
is in "alarm":
HVAC mode:
Else If: The evacuation input (Inputs
is in "alarm":
HVAC mode:
Else If: The smoke purge input (Inputs
is in "alarm":
HVAC mode:
}
Else
If:
Someone
control type (Configuration
run time, a 15 second delay is called out:
{
HVAC mode:
}
Else If: The System Mode is TEST:
{
HVAC mode:
}
Else If: The "soft stop" command (Service Test
is forced to YES:
{
HVAC mode:
}
Else If: The remote switch config (Configuration
UNIT
RM.CF)=2;
input state (Inputs
GEN.I
{
HVAC mode:
}
Else If: Configured for hydronic heat (Configuration
HEAT
HT.CF=4) or configured for dehumidification
with
modulating
DEHU
D.SEL=1) and the freeze stat switch trips
(Inputs
GEN.I
FRZ.S = ALRM)
{
HVAC mode:
}
Else
If:
Configured
(Configuration
SP
pressure sensor (Pressures
APPENDIX F — MODE SELECTION PROCESS
FIRE
("Fire Shut Down") OFF
("Disabled
") OFF
FIRE
("Pressurization ")
FIRE
("Evacuation
")
FIRE
("Smoke Purge
")
changed
the
machine's
UNIT
C.TYP) during
("Disabled
") OFF
("Test
")
("SoftStop Request")
"start/stop",
and
the
REMT)=ON:
("Rem. Sw. Disable") OFF
valve
reheat
(Configuration
("Freeze Stat Trip")
for
static
pressure
SP.CF = 1,2) and the static
AIR.P
SP) fails:
{
HVAC mode:
}
Else If: Configured for supply fan status monitoring
(Configuration
configured to shut the unit down on fan status fail
(Configuration
{
FSD)
HVAC mode:
Else If: Configured for return fan power exhaust
(Configuration
plenum pressure switch error
HVAC mode:
}
Else If: The unit is just waking up from a power reset
PRES)
{
HVAC mode:
}
EVAC)
Else If: A compressor is diagnosed as being "Stuck On"
{
HVAC mode:
PURG)
Else: The control is free to select the normal heating/
cooling HVAC modes:
}
HVAC mode:
—
The unit is off and no operating modes are active.
HVAC mode:
—
The economizer is at minimum vent position but
the supply air temperature has dropped below the
tempering vent set point. Gas or hydronic heat is
used to temper the ventilation air.
HVAC mode:
—
The economizer is at minimum vent position but
the combination of the outside-air temperature and
the economizer position has dropped the supply-air
S.STP)
temperature below the tempering cool set point.
Gas or hydronic heat is used to temper the
ventilation air.
HVAC mode:
—
The economizer is at minimum vent position but
the combination of the outside air temperature and
the economizer position has dropped the supply air
remote
temperature below the tempering cool set point.
Gas or hydronic heat is used to temper the
ventilation air.
HVAC mode:
—
The unit is operating in dehumidification with a
reheat device.
HVAC mode:
—
The unit is operating in the Dehumidification
mode.
HVAC mode:
—
This is a normal operation mode where no heating
or cooling is required and outside air is being
delivered to the space to control IAQ levels.
control
HVAC mode:
242
("Static Pres.Fail") OFF
UNIT
SFS.M
=
UNIT
SFS.S = YES)
("Fan Status Fail ") OFF
BP
BP.CF = 6) and there is a
("Plen.Press.Fail ") OFF
("Starting Up
") OFF
("Comp. Stuck On ")
("Off
")
("Tempering Vent ")
("Tempering LoCool")
("Tempering HiCool")
("Re-Heat
")
("Dehumidification")
("Vent
")
("Low Cool
")
1,2)
and
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Table of Contents
Troubleshooting
