Manual 2100-614I
Page
18 of 43
CONTROLLER WIRING
The MC4002 can be used for controlling two (2) air
conditioners with or without economizers. It can
also be configured for two (2) heat pumps without
economizers. Units with economizers will connect
differently than units without economizers; therefore, it
is important to use the correct connection diagram.
There are older style EIFM economizers and newer style
ECONWMT or WECOP economizers that the MC4002
controller system can work with, and also an option for
a remote Ethernet communication board. Therefore, it
is important to select the correct low voltage hook-up
diagram. See Table 1 — Hook-Up Diagram Selection
on Page 19.
SECURITY (LOCKING) FEATURE
The MC4002 controller can be locked such that
unauthorized persons cannot make any changes
to temperature setpoints 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 MC4002 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 the Change, Up
and Down arrow buttons simultaneously for 20
seconds until the display reads “uLoc”.
GENERATOR RUN FEATURE
If desired, the MC4002 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 both 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
MC4002 controller to this condition and disable lag air
conditioner run function.
A wire jumper is factory-installed across the G1 and
G2 terminals or main controller board. To utilize the
generator run feature, remove the jumper from G1 and
G2, and connect the generator normally closed (NC)
contacts that will open-on-run generator condition 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)
circuit breaker.
IMPORTANT:
The shelter DC battery power must be
connected to the controller and wired as shown in
controller wiring diagrams.
The backup DC power connection is polarity sensitive.
If polarity is reversed, the controller will not function on
backup power, no display and no alarm functions will
be evident.
