Manual 2100-538A
Page
16 of 23
The W3R/LV1 through W6R/LV1 variable capacity air
conditioners utilize dedicated controllers and
components to optimize this unit for cooling operation
from -40 degrees F up to 131 degrees F
(-40 degrees C
to +55 degrees C)
. These units are dual rated for 200-
240V operation on both 50 and 60 Hz. Please read the
following sequence of operation before attempting any
troubleshooting or repair. Troubleshooting and repair
procedures will be outlined below.
These models use a digital compressor and variable
speed indoor and outdoor motors. The motors and
compressor must be replaced with the exact same
component to maintain the above stated temperature
and voltage ranges of operation. The units are
controlled by a Bard digital thermostat/controller. This
thermostat/controller contains proprietary programming
and must be replaced with the exact same component to
ensure proper operation.
SEQUENCE OF OPERATION
MODES OF OPERATION
Cooling Mode - Normal cooling only mode
Heating Mode - Normal heating only mode
Auto - Auto changeover mode
Test Mode 1
- When in ‘Test Mode 1’, the compressor
will be turned ON and be locked ON as long as the unit
is in ‘Test Mode 1’. While in ‘Test Mode 1’ the
compressor will modulate from 20% to 100% to
maintain the occupied room setpoint. During the ‘Test
Mode 1’, if the space temperature falls 2°F below
setpoint, the first stage of heating will cycle ON. If the
space temperature falls 4°F below setpoint, the second
stage of heating will cycle ON. When the ‘Test Mode 1’
is terminated, the thermostat/controller will resume
normal operation.
Test Mode 2
- When in ‘Test Mode 2’, the compressor
will be turned ON and locked ON as long as the unit is
in the ‘Test Mode 2’. While in ‘Test Mode 2’ the
compressor will NOT modulate but will be locked on at
100% to maintain the occupied room setpoint. During
the ‘Test Mode 2’, if the space temperature falls 2°F
below setpoint, the first stage of heating will cycle ON.
If the space temperature falls 4°F below setpoint, the
second stage of heating will cycle ON. When the ‘Test
Mode 2’ is terminated, the thermostat/controller will
resume normal operation.
COOLING SEQUENCE
Compressor Operation
The cooling capacity of the WV series is controlled by
loading or unloading the compressor. On a call for
cooling, the unloader solenoid is energized for one
second to ensure pressure equalization in the
compressor. The compressor contactor, RLY 2, is then
energized and the compressor will start. A PI control
loop then calculates the compressor capacity needed to
reach set point and modulates the compressor .
Modulation range is from 20% to 100% capacity.
Modulation is accomplished by a pulse width modulated
signal from OUT 8 which energizes the solid state relay
(SSR) and energizes or de-energizes the unloader
solenoid. The required compressor capacity is
calculated every 15 seconds.
20% load
means 0 VDC for 3.0 seconds and 5 VDC for
12.0 seconds from OUT 8.
30% load
means 0 VDC for 4.5 seconds and 5 VDC for
10.5 seconds from OUT 8.
40% load
means 0 VDC for 6.0 seconds and 5 VDC for
9.0 seconds from OUT 8.
50% load
means 0 VDC for 7.5 seconds and 5 VDC for
7.5 seconds from OUT 8.
60% load
means 0 VDC for 9.0 seconds and 5 VDC for
6.0 seconds from OUT 8.
70% load
means 0 VDC for 10.5 seconds and 5 VDC
for 4.5 seconds from OUT 8.
80% load
means 0 VDC for 12.0 seconds and 5 VDC
for 3.0 seconds from OUT 8.
90% load
means 0 VDC for 13.5 seconds and 5 VDC
for 1.5 seconds from OUT 8.
100% load
means 0 VDC for 15 seconds and 5 VDC for
0.0 seconds from OUT 8.
