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9
In programming screen #44, you are asked to enter
a reset ratio factor. This is the number of degrees
that the discharge air setpoint is raised when the
room temperature falls below the heating setpoint by
1 degree if the analog output is set for heating, or the
number of degrees that the discharge air setpoint is
lowered when the room temperature rises above the
cooling setpoint by 1 degree if the analog output is set
for cooling.
OUTDOOR AIR TEMPERATURE SENSING
The SZ1018 accept a remote 1000
Ω
outdoor tem-
perature sensor (TS1003) for monitoring purposes.
(See setup instructions for dipswitch placement for
this option.)
Choose YES in programming screen #45 only if you
are using an outdoor air sensor and you want to
enable the outdoor air heating and cooling lockout
functions (Do not use with Zoning System). If NO is
chosen, the outdoor air is still monitored.
When the function is enabled, a COOLING LOCKOUT
TEMP and HEATING LOCKOUT TEMP are entered
in steps #46 and #47. If the outdoor temperature falls
below the COOLING LOCKOUT TEMP, all cooling
stages will be locked out and will remain locked out
until the outdoor air temperature rises 2° above the
lockout temperature. If the outdoor temperature rises
above the HEATING LOCKOUT TEMP, all heating
stages will be locked out and will remain locked out
until the outdoor air temperature falls 2° below the
lockout temperature.
The outdoor air span is -40 to 160 °F (-40.0 to 71.1
°C).
FAN PROVING
The SZ1018 allow DI1 to be set for fan proving to
protect equipment on fan failure. To utilize this, a
pressure or current switch is required, which indicates
when the fan is running. If the thermostat turns on the
FAN, and DI1 is not closed after thirty seconds, the
system will go to OFF, disabling all outputs, the fan
LED will turn off, and the service LED will be lit until
the system is manually reset by switching the system
to a mode other than OFF.
DI2 SETPOINT SHIFT
The SZ1018 allow DI2 to be set for setpoint shift for
energy demand setback. This is enabled by setting
DI2 to the MONITOR mode. A digital contact that
closes when setback is needed should be wired into
DI2. You may specify a number of degrees such that,
when the thermostat is operating in the occupied
mode, and DI2 is closed, the heating setpoint will
be lowered this number of degrees, and the cooling
setpoint will be raised this number of degrees. The
fan will continue to operate according to its occupied
setting. If you are using DI2 as monitor for another
purpose, make sure to set the setpoint and shift value
to zero.
STAGE OUTPUT PARAMETERS
Heat Setpoint
Cool Setpoint
ON
ON
ON
ON
OFF
OFF
OFF
OFF
Differential
Differential
Offset
Offset
Differential
Differential
The SZ1018 will control up to two stages of either
heating or cooling.
For each stage, you may specify an offset and a differ-
ential value. The offset value is the amount away from
the setpoint a stage will turn off. By assigning a stage
a value other than zero, you “anticipate” that the resid-
ual heat or cooling in the duct or the other stages will
bring the temperature back to setpoint. In most cases,
the first stage is set to zero. The differential value is
the difference between the on and off points.
ANALOG OUTPUT PARAMETERS
4 20
4 20
4 20
4 20
4 20
4 20
P
Z
o
n
e
T
e
m
p
Output
(mA)
P
Output
(mA)
DIRECT ACTING
REVERSE ACTING
P
P
Output
(mA)
Output
(mA)
Z
o
n
e
T
e
m
p
P
P
Output
(mA)
Output
(mA)
P
P
Z
o
n
e
T
e
m
p
CSP
CSP
HSP
HSP
CSP
CSP
HSP
HSP
