Manual 2100-715B
Page
18 of 25
Service Hints
1. Caution owner/operator to maintain clean air filters
at all times and also not to needlessly close off
supply and return air registers. This reduces airflow
through the system, which shortens equipment
service life as well as increasing operating costs.
2. Check all power fuses or circuit breakers to be sure
they are the correct rating.
3. Periodic cleaning of the outdoor coil to permit full
and unrestricted airflow circulation is essential
.
Sequence of Operation
COOLING – Circuit R-Y1 makes at thermostat pulling
in compressor contactor, starting the compressor and
outdoor motor. (See
NOTE
under
CONDENSER FAN
OPERATION
on page 17 concerning models equipped
with low ambient control.) The G (indoor motor)
circuit is automatically completed by the thermostat
on any call for cooling operation or can be energized
by manual fan switch on subbase for constant air
circulation. On a call for heating, circuit R-W1 makes
at the thermostat pulling in heat contactor for the strip
heat and blower operation.
Balanced Climate
TM
Mode
Balanced Climate™ is a great comfort feature that can
easily be applied under any normal circumstances.
If the Bard air conditioning system is being set up
in a typical environment where 72°F is the lowest
cooling setpoint, remove the Y1/Y2 jumper and install
a 2-stage cooling thermostat. This will increase the
humidity removal up to 35% and provide a much more
comfortable environment.
If the application is likely to require air conditioning
operation below 60°F outdoor conditions, a low ambient
control (LAC) kit must be installed.
The LAC kit is
equipped with an outdoor temperature switch that
disables Balanced Climate mode when the outdoor
temperature drops below 50°F. This prevents potential
evaporator coil freeze up issues. The LAC kit also comes
with an evaporator freeze protection thermostat that cuts
out the compressor if the evaporator begins to freeze up.
If the unit is being installed with any ventilation
package, a Bard LAC kit must be installed.
Failure to
utilize an LAC with any air conditioner can cause coil
freeze up.
Balanced Climate can readily be applied to duct-free
(supply and return air grille) applications. It may also
be applied to ducted applications with
limited static
of 0.10" ESP (total including both supply and return
statics)
. Consult Bard Application Engineering for
details prior to implementation.
CAUTION:
Balanced Climate is not a replacement for
a dehumidification (hot gas reheat) unit for extreme
applications, but rather an enhancement feature for
limited climates and applications.
Vent Connection Plug
All units are equipped with a vent connection plug in
the side of the control panel for the different ventilation
packages to plug in to. If the compressor will not start
and there is no "Y1" at the compressor control module,
first check to make sure that either the optional vent is
plugged into the vent connection plug or the supplied
jumper plug is in place.
The unit will not operate
without anything plugged in.
This plug is located on
the side of the control panel behind the front vent door
(behind the filter access door). If the unit is supplied
with a factory-installed vent package, it will be plugged
in but the jumper plug will also be tethered next to the
connection for troubleshooting purposes, if necessary.
Compressor Control Module
The compressor control module (CCM) is standard on
all models covered by this manual.
Features
Delay-on-Make Timer
Short Cycle Protection/Delay-on-Break
Low Pressure Detection
High Pressure Detection
LPC and HPC Status LEDs
Test Mode
Brownout Protection with Adjustment
Delay-on-Make Timer
A delay-on-make timer is included to be able to delay
startup of the compressor. This is desired when more
than one unit is on a structure so that all of the units
do not start at the same time which could happen
after a power loss or building shutdown. The delay-
on-make time period is 2 minutes plus 10% of the
delay-on-break time period. To ensure that all of the
units do not start at the same time, adjust the delay-
on-break timer on each unit to a slightly different
delay time.
Short Cycle Protection/Delay-on-Break
An anti-short cycle timer is included to prevent short
cycling the compressor. This is adjustable from 30
seconds to 5 minutes via the adjustment knob (see
Figure 9). Once a compressor call is lost, the time
period must expire before a new call will be initiated.
Low Pressure Detection
Low pressure switch monitoring allows for a lockout
condition in a situation where the switch is open. If
the low pressure switch remains open for more than
2 minutes. the CCM will de-energize the compressor
for the delay-on-break time. If the switch closes again,
it will then restart the compressor. If the switch trips
again during the same Y call, the compressor will be
de-energized and the alarm terminal will be energized
indicating an alarm. The blue LED will light and stay on
until power is cycled to the control or a loss of voltage
is present at Y terminal for more than ½ second.
