R e s i d e n t i a l H & V - 6 0 H z H F C - 4 1 0 A
R e v. : 9 M a r c h , 2 0 1 1 B
24
G e o t h e r m a l H e a t P u m p S y s t e m s
ECM Blower Control
The ECM fan is controlled by an interface board that
converts thermostat inputs and
¿
eld selectable CFM
settings to signals used by the ECM motor controller.
Units manufactured before July 2005 have version I (P/N
69243707). Units manufactured after July 2005 have version
II (P/N 17B0019N01). 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).
HFC-410A packaged units built after May 2009 have ECM
controller version III (P/N 17B0034N01). This controller
includes logic and a relay to control the HWG functions.
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 dehumidi
¿ cation mode settings while the unit
is powered.
There are four different air
À
ow settings from lowest air
À
ow
rate (speed tap 1) to the highest air
À
ow 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 dehumidi
¿
cation mode.
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 dehumidi
¿
cation mode is selected. Consult
submittal data or speci
¿
cations catalog for the speci
¿
c unit
series and model to correlate speed tap setting to air
À
ow in
CFM.
Heating Settings: The heating setting determines the heating
CFM for Tranquility 27
®
(TT) and Tranquility 20 (TS) units.
Tap 1 is the lowest CFM setting, while tap 4 is the highest
CFM setting. Consult submittal data or speci
¿
cations catalog
for the speci
¿
c unit series and model to correlate speed tap
setting to air
À
ow 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 speci
¿
cations catalog for the speci
¿
c unit series and
model to correlate speed tap setting to air
À
ow 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 air
À
ow by +/- 15%. The +/-
settings are used to “
¿
ne tune” air
À
ow 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.
Dehumidi
¿
cation Mode Settings: The dehumidi
¿
cation mode
setting provides
¿
eld selection of humidity control. When
operating in the normal mode, the cooling air
À
ow settings
are determined by the cooling tap setting above. When
dehumidi
¿
cation is enabled there is a reduction in air
À
ow
in cooling to increase the moisture removal of the heat
pump. Consult submittal data or speci
¿
cations catalog for
the speci
¿
c unit series and model to correlate speed tap to
air
À
ow in CFM. The dehumidi
¿
cation mode can be enabled in
two ways.
1.
Constant Dehumidi
¿
cation Mode: When the
dehumidi
¿
cation 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 air
À
ow). Any time the unit is running in
the cooling mode, it will operate at the lower air
À
ow
to improve latent capacity. The “DEHUM” LED will be
illuminated at all times. Heating air
À
ow is not affected.
NOTE: Do not select dehumidi
¿
cation mode if cooling
setting is tap 1.
2.
Automatic (Humidistat-controlled) Dehumidi
¿
cation
Mode: When the dehumidi
¿
cation 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 air
À
ow will only be reduced when the
humidistat senses that additional dehumidi
¿
cation 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 dehumidi
¿
cation mode.
Heating air
À
ow is not affected.
NOTE: Do not select
dehumidi
¿ cation mode if cooling setting is tap 1.
