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APPENDIX E — MODE SELECTION PROCESS
The following section is to be used in conjunction with
Fig. 7 on page 43. 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” statement is true, then that mode will be en-
tered. The “Else” statement refers to other possible choices.
If the System Mode is OFF:
{
If the fire shut down input (Inputs
FIRE
FSD)
is in “alarm”:
HVAC mode: ("Fire Shut Down ") OFF
Else
HVAC mode: ("Disabled ") OFF
}
Else If: The rooftop is not in “factory test” and a fire
smoke-control mode is “alarming”:
{
If the pressurization input (Inputs
FIRE
PRES)
is in “alarm”:
HVAC mode: ("Pressurization ")
Else If the evacuation input (Inputs
FIRE
EVAC)
is in “alarm”:
HVAC mode: ("Evacuation ")
Else If the smoke purge input (Inputs
FIRE
PURG)
is in “alarm”:
HVAC mode: ("Smoke Purge ")
}
Else If: Someone changed the machine’s
control type (Configuration
UNIT
C.TYP) during
run time, a 15-second delay is called out:
{
HVAC mode: ("Disabled ") OFF
}
Else If: The System Mode is TEST:
{
HVAC mode: ("Test ")
}
Else If: The “soft stop” command (Service Test
S.STP)
is forced to YES:
{
HVAC mode: ("SoftStop Request")
}
Else If: The remote switch configuration (Configura-
tion
UNIT
RM.CF)=2; “start/stop”, and the remote
input state (Inputs
GEN.I
REMT)=ON:
{
HVAC mode: ("Rem. Sw. Disable") OFF
}
Else If: Configured for hydronic heat (Configuration
HEAT
HT.CF=4) or configured for dehumidification
with modulating valve reheat (Configuration
IAQ
DEHU
D.SEL=1) or configured for heat reclaim using
modulating valve (Configuration
IAQ
DEHU
H.SEL=2 and Configuration
IAQ
DEHU
D.SEL=5) and the freeze stat switch trips (Inputs
GEN.I
FRZ.S = ALRM) :
{
HVAC mode: ("Freeze Stat Trip")
}
Else If: Configured for static pressure control
(Configuration
SP
SP.CF = 1,2) and the static
pressure sensor (Pressures
AIR.P
SP) fails:
{
HVAC mode: ("Static Pres.Fail") OFF
}
Else If: Configured for supply fan status monitoring
(Configuration
UNIT
SFS.M = 1,2) and
configured to shut the unit down on fan status fail
(Configuration
UNIT
SFS.S = YES) and a fan sta-
tus failure occurs:
{
HVAC mode: ("Fan Status Fail ") OFF
Else If: Configured for return fan tracking
(Configuration
BP
BP.CF = 2) and there is a
plenum pressure switch error (Inputs
GEN.I
PP.SW=HIGH):
HVAC mode: ("Plen.Press.Fail ") OFF
}
Else If: Configured for power monitoring
(Configuration
UNIT
PW.MN) = YES and there is
a power error (Input
GEN.I
PWR.F=ALRM):>
{
HVAC mode: ("3-Phase Pwr Fail") OFF
}
Else If: There is an air pressure safety switch error
(Inputs
GEN.I
SP.SS=HIGH):
{
HVAC mode: ("Air.Pres.Sw.Fail") OFF
}
Else If: There is a VFD1 fault detected (Run Status
VFDS
S.VFD
LCF!=0) or
There is VFD1 communications failure and the supply fan
is not in bypass mode (Inputs
GEN.I
SF.BY=OFF):
{
HVAC mode: ("Supply VFD Fault") OFF
}
Else If: There is an RCB1 communications failure:
{
HVAC mode: ("RCB comm failure") OFF
}
Else If: The unit is just waking up from a power reset:
{
HVAC mode: ("Starting Up ") OFF
}
Else If: A compressor is diagnosed as being "Stuck On":
{
HVAC mode: ("Comp. Stuck On ")
}
Else: The control is free to select the normal heating/cooling
HVAC modes:
{
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