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Ultra Classic (VT) Series
ECM FAN MOTOR
“fine tune” airflow adjustments. The TEST setting
runs the ECM motor at 70% torque, which causes
the motor to operate like a standard PSC motor, and
disables the CFM counter.
Dehumidification Mode settings: The
dehumidification mode setting provides field
selection of humidity control. When operating in
the normal mode, the cooling airflow settings are
determined by the cooling tap setting above. When
dehumidification is enabled there is a reduction in
airflow in cooling to increase the moisture removal
of the heat pump. Consult submittal data or
specifications catalog for the specific unit series and
model to correlate speed tap to airflow in CFM. The
dehumidification mode can be enabled in two ways.
1.
Constant Dehumidification Mode:
When the
dehumidification mode is selected (via DIP
switch or jumper setting), the ECM motor will
operate with a multiplier applied to the cooling
CFM settings (approx. 20-25% lower airflow).
Any time the unit is running in the cooling mode,
it will operate at the lower airflow to improve
latent capacity. The “DEHUM” LED will be
illuminated at all times. Heating airflow is not
affected. NOTE: Do not select dehumidification
mode if cooling setting is tap 1.
2. Automatic (Humidistat-controlled)
Dehumidification Mode:
When the
dehumidification mode is selected (via DIP
switch or jumper setting) AND a humidistat
is connected to terminal DH (version II) or
HUM (version I), the cooling airflow will only
be reduced when the humidistat senses that
additional dehumidification is required. The DH
(or HUM) terminal is reverse logic. Therefore, a
humidistat (not dehumidistat) is required. The
“DEHUM” LED will be illuminated only when the
humidistat is calling for dehumidification mode.
Heating airflow is not affected. NOTE: Do not
select dehumidification mode if cooling setting is
tap 1.
Fan speeds are selected with jumpers for version
I or via a nine position DIP switch for version II. To
take full advantage of the ECM motor features, a
multi-stage thermostat should be used (2-stage
heat/2-stage cool or 3-stage heat/2-stage cool).
Note:
Power must be off to the unit for at least three
seconds before the ECM motor will recognize a
speed change. The motor will recognize a change
in the CFM Adjust or dehumidification mode
settings while the unit is powered.
There are four different airflow settings from lowest
airflow rate (speed tap 1) to the highest airflow rate
(speed tap 4). The charts below indicate settings for
both versions of the ECM interface board, followed
by detailed information for each setting.
Cooling
settings: The cooling setting determines
the cooling (normal) CFM for all units with ECM
motor. Cooling (normal) setting is used when the
unit is not in dehumidification mode. This setting
also determines the heating CFM for Genesis (GS)
units. Tap 1 is the lowest CFM setting, while tap 4 is
the highest CFM setting. To avoid air coil freeze-up,
tap 1 may not be used if the dehumidification mode
is selected. Consult submittal data or specifications
catalog for the specific unit series and model to
correlate speed tap setting to airflow in CFM.
Heating
settings: The heating setting determines
the heating CFM for Tranquility 27™ (TT) and
Tranquility 20™ (TS) units. This setting is not used
for Genesis (GS) units. Tap 1 is the lowest CFM
setting, while tap 4 is the highest CFM setting.
Consult submittal data or specifications catalog
for the specific unit series and model to correlate
speed tap setting to airflow in CFM.
Auxiliary/Emergency Heat
settings: The auxiliary/
emergency heat setting determines the CFM when
the unit is in auxiliary heat or emergency heat
mode. This setting is used for residential units with
internal electric heat. When auxiliary electric heat
is energized (i.e. compressor and electric heat), the
greater of the auxiliary/emergency or heating setting
will be used. A “G” (fan) signal must be present from
the thermostat for electric heat to operate. Consult
the submittal data or specifications catalog for the
specific unit series and model to correlate speed tap
setting to airflow in CFM.
CFM Adjust
settings:
The CFM adjust setting
allows four selections. The NORM setting is the
factory default position. The + or – settings adjust
the airflow by +/- 15%. The +/- settings are used to
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