Bryant GT-PG (50YE) ユーザーズマニュアル

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Bryant Geothermal Heat Pump Systems
GT-PG
39
Residential Products Technical Guide
GT-PG ECM Control Features
The ECM fan is controlled by an interface board that 
converts thermostat inputs and fi 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 between July 2005 and 
May 11, 2009 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 and III. 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 11, 2009 have 
a ECM controllers 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 dehumidifi cation mode settings while the unit 
is powered.
There are four different airfl ow settings from lowest airfl ow 
rate (speed tap 1) to the highest airfl 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 
dehumidifi cation mode. This setting also determines the 
heating CFM for GT-G (50YC) 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 dehumidifi cation 
mode is selected. Consult submittal data or specifi cations 
catalog for the specifi c unit series and model to correlate 
speed tap setting to airfl ow in CFM. 
Heating Settings
: The heating setting determines the 
heating CFM for GT-PX (50YD) and GT-PG (50YE) units. 
This setting is not used for GT-G (50YC) units. Tap 1 is 
the lowest CFM setting, while tap 4 is the highest CFM 
setting. Consult submittal data or specifi cations catalog for 
the specifi c unit series and model to correlate speed tap 
setting to airfl 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 specifi cations catalog for the 
specifi c unit series and model to correlate speed tap setting 
to airfl 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 airfl ow by +/- 15%. 
The +/- settings are used to “fi ne tune” airfl 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.
Dehumidifi cation Mode Settings
: The dehumidifi cation 
mode setting provides fi eld selection of humidity control. 
When operating in the normal mode, the cooling airfl ow 
settings are determined by the cooling tap setting above. 
When dehumidifi cation is enabled there is a reduction in 
airfl ow in cooling to increase the moisture removal of the 
heat pump. Consult submittal data or specifi cations catalog 
for the specifi c unit series and model to correlate speed 
tap to airfl ow in CFM. The dehumidifi cation mode can be 
enabled in two ways. 
1.   Constant Dehumidifi cation Mode: When the 
dehumidifi 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 airfl ow). Any time the unit is running in 
the cooling mode, it will operate at the lower airfl ow 
to improve latent capacity. The “DEHUM” LED will be 
illuminated at all times. Heating airfl ow is not affected. 
NOTE: Do not select dehumidifi cation mode if cooling 
setting is tap 1.
2.   Automatic (Humidistat-controlled) Dehumidifi cation 
Mode: When the dehumidifi 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 airfl ow will only be reduced when the 
humidistat senses that additional dehumidifi 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 dehumidifi cation mode. 
Heating airfl ow is not affected. NOTE: Do not select 
dehumidifi cation mode if cooling setting is tap 1.