TCS Basys Controls SZ1017a Product Manual - page 17
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17
should be on but the heating or cooling LED is off, check
the fan and system switch modes. Also, check the heat-
ing and cooling setpoints, offsets and differentials, and
the room temperature to be sure heating or cooling
should be on. If using outdoor air heating and cooling
lockouts, or discharge air high and low limits, check
their values to be sure heating or cooling is allowed. If
heating or cooling is off, but the corresponding LED is
on, check the wiring. Short terminals “R” to “Y/W1” or
“Y/W2” and see if the heating or cooling comes on. This
is a check for a mechanical relay failure.
Wrong temperature display
If any of the temperatures are reading slightly high or low,
there are three adjustment pots located in the cover to
adjust them. “T1” is for the room temperature, “T2” is for
the discharge air temperature, and “T3” is for the outdoor
air temperature. If the temperature is at a minimum or maxi-
mum reading, check the sensor dipswitch positions. (See
setup instructions.) Check for wiring problems (opens or
shorts). A remote 1000
Ω
sensor should read 108 to 109
Ω
at room temperature.
Service led is on
If the service LED is on, it may be for monitoring purpos-
es or it may indicate a critical problem. The first monitor-
ing screen accessed by pressing the service status but-
ton will display why the light is on.
outputs Will not Shut off
First check the room temperature and the setpoints and
determine whether the output should be on. There are
delays and minimum on and off times for the fan and
heating and cooling stages. Also, check the service
status menus to verify that the outputs are on. Turning
the system to “off” will instantly turn all outputs off. The
thermostat can be reset by pressing the system switch
button and the service status button simultaneously.
Analog output not Working Properly
Check wiring. A separate transformer should be used for
the SZ1017a, SZ1041, SZ1051, or SZ1053, and a sepa-
rate transformer should be used for the motor(s). Check
to make sure that the analog output is programmed cor-
rectly.
Check the Service Menu. The Mod Out Screen will tell
you what the SZ1041 or SZ1051 is trying to put out.
Compare this with the actual position on the heating or
cooling device.
Main Monitoring Screen. Press the
service button to access the following
screens. (Date not shown on SZ1017a.)
Service Screen. This message may
be followed by any or all of the follow-
ing: CHECK FILTER, CHECK FAN,
DISCHARGE HIGH, DISCHARGE LOW,
or CHECK DI2.
Discharge Air Temperature Screen.
Shows discharge air temperature if sen-
sor is used.
Outdoor Air Temperature Screen. Shows
outdoor air temperature if sensor is used.
override Status Screen.
Shows wheth-
er the override is active and if so, how
many minutes remaining.
heat or Cool Stages Status Screen.
Shows the status of the first and second
stages of heating or cooling.
Modulating Output 1 and 2 Status
Screen. Shows the percentage of modu-
lating output 1 and 2.
There are two conditions that must be met before the
economizer analog output will modulate. First, there
must be a call for cooling. Second, the outdoor air
temperature must be less than the setting set in pro-
gramming step #31b (for the SZ1041) or #30a (for the
SZ1051).
Put the SZ1041 or SZ1051 into occupied mode. You
should be able to adjust the output by going to pro-
gramming step #35b (for the SZ1041) or #34a (for the
SZ1051) and varying the minimum position setting. You
need to exit programming before the change will take
effect.
SeRviCe SCReenS
Continually pressing the service status button allows
more extensive monitoring. The screens are shown on
the following page.
T1
T2
T3
1 2
1 2 3 4 5
adjust display contrast
service
status
MOD OUT 25%
DI1 OPEN
6.
FOR
THE
SZ1017a