Bard QW242D Installation Instructions Manual - page 27
Manual
2100-418F
Page
27 of 49
1
Maximum ESP (inches WC) shown is with 1" thick disposable filter (reduced by .2 for 2" filter).
2
Rated CFM for ducted applications – required for maximum performance rating. To obtain full CFM on
models QW361, QW421, QW481 and QW601 locate low voltage terminal strip in the circuit breaker box.
There is a pink jumper wire with both ends attached to terminal marked “G2”. Move one end of the jumper to
terminal “Y”.
3
Optional CFM – the unit is shipped from the factory set to operate at the optional CFM level shown.
This provides lower operating sound levels for non-ducted, free discharge applications. This reduces
system capacity performance by approximately 2% at the same energy efficiency.
4
Continuous fan CFM is the total air being circulated during continuous fan mode.
TABLE 4
INDOOR BLOWER PERFORMANCE
NOTE: These units are equipped with a variable speed (ECM) indoor motor that automatically
adjusts itself to maintain approximately the same rate of indoor airflow in both heating and
cooling, dry and wet coil conditions, and at both 230/208 or 460 volts.
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1
NOTE: The CS2000A1 (or other means for ventilation
control) must be used if any mechanical
(motorized) ventilation options are installed.
Dehumidification can be set to be available only when
CS2000A1 is active or to be available continuously by
switching a jumper at the relay logic board.
When the humidity is above the setpoint of the
humidistat, the compressor circuit and the three way
valve are energized and the evaporator airflow is
reduced. The three way valve directs hot discharge gas
into a separate desuperheating condenser circuit that
reheats the conditioned air before it is delivered to the
room. If the return air thermostat senses a temperature
below 65° during dehumidification, dehumidification is
cancelled. When the humidistat is satisfied the system
switches back to normal air conditioning mode.
If the thermostat calls for cooling during
dehumidification mode, the call for cooling takes
precedence over the dehumidification and the unit will
cool until the thermostat is satisfied. Once the call for
cooling is satisfied, the unit may continue to
dehumidify.
If the thermostat calls for first stage heat when the unit
is in dehumidification mode, the unit will continue to
run in dehumidification mode until a second stage heat
call is received.
If the unit is running in heat pump mode and the
humidistat calls for dehumidification, the
dehumidification mode takes precedence over the heat
pump heating mode. The unit will not return to the
heating mode until second stage heating is called for.
REFRIGERANT TUBE SCHEMATIC FOR
REHEAT COIL
Figure 18 shows the refrigerant gas flow through the
reheat coil during the dehumidification mode.
When the unit is in standard cooling, Figure 19, or
heating mode the reheat coil is inactive.
PRESSURE SERVICE PORTS
High and low pressure service ports are installed on all
units so that the system operating pressures an be
observed. Pressure curves can be found later in the
manual covering all models on both cooling and
heating cycles. It is imperative to match the correct
pressure curve to the unit by model number. Upper and
lower service doors must be attached to obtain proper
reading.