2800 LAURA LANE • MIDDLETON, WI 53562 • (800) 288-9383 • FAX (608) 836-9044 • www.tcsbasys.com
7
the room occupied, such as with a switch or wind-up
timer. If each occupancy period is about the same, (the-
aters, meetings) another option is to set the DI3 to exter-
nal time clock, and use the timed override button to put
the unit in occupied mode.
To make the unit always occupied, set DI3 to external
time clock and short the DI3 terminal to ground.
TWO-PIPE FAN COIL OPERATION
For two-pipe fan coil operation, in step #31 select YES.
You must then select whether the system is HEATing
only, COOLing only or heating and cooling (H&C) in step
#32.
When using a two-pipe system to do both heating and
cooling, the SZ1061 and SZ1062 need to know whether
hot or cold water is available. This is accomplished by
either the use of a mechanical aquastat (bulb thermo-
stat) connected to terminals DI1 and 24-, or by the use
of a temperature sensor connected to T2 and T2
(SZ1062 only). If using a mechanical thermostat, select
DIGITAL in step #33, and select normally closed N.C. or
normally open N.O. In step #34. If using a temperature
sensor, select ANALOG in step #33 and place a change-
over setpoint in step #35. When the temperature is
greater than this setpoint, it is assumed hot water is
available and heating is done. When the temperature is
less than this setpoint, it is assumed cold water is avail-
able and cooling is done.
When using a two-pipe system to do both heating and
cooling, only Y1 is used. When using a two-pipe system
to do only heating, only W1 is used. When using a two-
pipe system to do only cooling, only Y1 is used.
FOUR-PIPE FAN COIL OPERATION
For four-pipe fan coil operation, in step #31 select NO.
Four-pipe fan coil operation assumes that there are two
water sources available (hot and cold), that are each
controlled by its own valve. W1 output one is used for
heating and Y1 is used for cooling.
PIPE TEMPERATURE SENSING
The SZ1062 accepts a remote pipe temperature sensor
for monitoring purposes or for changeover in a two-pipe
system. (See setup instructions for dipswitch placement
for this option.)
The pipe temperature span is 0 to 150°F (-17.8 to
65.6°C).
DIGITAL OUTPUTS
The digital outputs on the SZ1061 and SZ1062 are used
to control the heating and cooling in a space. Digital out-
put W1 is used to control heating and digital Y1 is used
to control cooling with a four pipe system. Only digital Y1
is used with a two-pipe system set for heat and cool
(H&C).
DI2 SETPOINT SHIFT
The SZ1061 and SZ1062 allow DI2 to be set for setpoint
shift for energy demand setback. 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 shift value to zero.
AUXILIARY RELAY OUTPUT PARAMETERS
The auxiliary relay of the SZ1062 will control one stage
of either heating or cooling, or can be used as a time-
clock output.
If the auxiliary relay is used as heating or cooling stage,
you may specify an offset and a differential value. The
offset value is the amount away from the setpoint a
stage will turn off. By assigning a value other than zero,
you "anticipate" that the residual heat or cooling in the
duct will bring the temperature back to setpoint. In most
cases, a first stage is set to zero. The differential value
is the difference between the on and off points. Using an
offset value greater than or equal to the differential of a
heat or cooling output will allow the relay to come on
after first stage is achieved. Strip heat, for example.
If the auxiliary relay is used as a timeclock output, it is
selectable whether the relay is open or closed during the
occupied period. During the unoccupied period, the
opposite will occur.
Keep in mind that although it is an isolated relay (sepa-
rate common terminal), it is rated at 24 VAC @ 2A. For
loads that exceed this, use an external relay. The follow-
ing chart shows operation of W1, Y1 and auxiliary relay.
