Manual 2100-484E
Page 9 of 22
SEQUENCE OF OPERATION – HEATING
(AIR CONDITIONERS W/ELECTRIC HEAT)
First stage heating set point is the dead band setting
below first stage cooling set point (the SP entered into
the program). The dead band is adjustable from 2-20F
(1-10C), and the factory default is 10F (5C).
Second stage heating set point is 2F (1C) cooler than
Stage 1.
DC3003 only: Stage 3 heat is the electric heater in
HVAC #3.
SECURITY (LOCKING) FEATURE
The DC3000 controller can be locked such that
unauthorized persons cannot make any changes to
temperature set points or any other selectable
parameters of the controller system.
The ON/OFF and Comfort buttons remain fully active
for their normal intent. The Advance/Change/Save
button remains active for the Advance feature only,
which allows the position of the lead and lag air
conditioners to be swapped (reversed). The Program
button remains partially active - allowing the review of
temperature sensor(s) actual reading of temperature, and
the current settings/choices that have been chosen.
However, no changes can be made when the controller
is locked, and if the change button is pressed when in
the Program mode, the display will come up showing
“Locd” instead of flashing the selectable choices for that
parameter. The default (DEF) reset capability is also
disabled when the controller is in locked mode.
Locking and Unlocking the DC3000 Controller:
1.Locking the controller requires using 3 buttons
while the controller is in the normal operating (run)
mode.
2.Press and hold the Advance/Change/Save button
and the Up and Down arrow buttons simultaneously
for 20 seconds until the display shows “Locd”.
3.To unlock the controller, press and hold the
Advance/Change/Save button and the Up and Down
arrow buttons simultaneously for 20 seconds until
the display shows “uLoc”.
GENERATOR RUN FEATURE
If desired, the DC3000 controller can be signaled from a
standby generator system to lockout (disable operation)
of the lag air conditioning system. This is sometimes
mandated if the generator size is not sufficient to handle
the building load (amperage) and that of all air
conditioning systems.
A normally closed (NC) dry contact as part of generator
controls is required. These contacts must open when the
generator is started, and such action will signal the
DC3000 controller to this condition and disable lag air
conditioner run function.
On DC3003 with 3 HVAC’s, only the “lag” A/C is
locked out; the lead A/C and A/C #3 will still function.
A wire jumper is factory-installed across the G1 and G2
terminals on main controller board. To utilize the
generator run feature, remove the jumper from G1 and
G2, and connect the generator normally closed (NC,
open-on-run) to the G1 and G2 terminals.
BACKUP DC POWER CONNECTION
There are input connections available for -24VDC or
-48VDC (-20 to -56V) backup power connection.
Making this connection will maintain microprocessor
operation, front panel display, LED signaling, and alarm
relay operation during periods of commercial power
outages and when no standby generator is available.
This circuit is protected by a replaceable .5A (500mA)
250V fuse.
IMPORTANT