Ecm Interface Board - Bryant Gt 024 Installation Instructions Manual

ECM INTERFACE BOARD

Refer to Fig. 7, item (12) for ECM interface board location. In
addition to providing a connecting point for thermostat wiring, the
interface board also translates thermostat inputs into control
commands for the Electronic Commutated Motor (ECM) DC fan
motor and provides thermostat signals to unit's UPM board. The
thermostat connections and their functions are as follows:
10
9 8
7 6
(1) Motor Harness Plug
(2) Blower CFM Adjustment
(3) Motor Settings
(4) Dehumidification Indication
(5) Thermostat Contact Inputs
(6) CFM Count Indicator
Fig. 13 - - ECM Interface Board
NOTE: CFM LED indication is an approximation. Utilize
conventional Test and Balance equipment for accurate airflow
measurement.
S CFM count indicator (see Fig. 13, item 6) blinks to indicate
approximate airflow in CFM and may flicker when the unit is off.
S Each blink of the LED represent approximately 100 CFM of air
delivery so if the LED blinks 12 times, pauses, blinks 12 times,
etc. the blower is delivering approximately 1200 CFM.
THERMOSTAT
24V OUTPUTS
DE-HUMIDIFICATION CALL
COOLING STAGE 1
COOLING STAGE 2
HEATING STAGE 1
HEATING STAGE 2
SW ITCH OVER VALVE
BLOW ER
24VAC (HOT)
24VAC (COMMON)
Fig. 15 - - Cool to Dehumidify Application for Thermostats with Dehumidification
1
11
5 2 4
(7) Thermostat Input Status Indication
(8) Reheat Digital Outputs
(9) Thermostat Outputs
(10) 24 VAC
(11) Dehumidification Method Selector
Dry
Contact
Y1
Y2
W 1
W 2/E
O/B
G
R
C
(Not required for Cor / Housewise thermostats)
Dehumidification Mode
Position the HGRH DIP switch in the "NO" (OFF) position.
When the switch is in this position, upon a dehumidification call,
the unit will operate at a lower speed to increase dehumidification
while cooling. See Fig. 14.
3
Fig. 14 - - Dehumidification Method Selector
Dry Contact Left side terminal strip in the stat, D1, D2
YI First Stage Compressor Cool
Y/Y2 Second Stage Compressor Cool
W1 Auxiliary Electric Heat
(runs in conjunction with compressor)
W2/E Emergency Heat (electric heat only)
O Reversing Valve (energized in cooling)
G Fan
A14124
R Transformer 24 VAC Hot
C Transformer 24 VAC Common
NOTE: When unit is used with Carrier and Bryant thermostats
with Relative Humidity Control (Carrier Edge TP- -PRH or
TP- -NRH / Bryant Preferred T6- -PRH or T6- -NRH), the unit's
dehumidification mode is in reverse logic and will not activate
dehum unless a relay, as shown in Fig. 15, is used. A simplified
explanation of the reverse logic follows.
No Dehum Demand: Dh - - energized
Dehum Demand:
C
RELAY
H HUMIDISTAT
Y1
COOLING STAGE 1
Y2
COOLING STAGE 2
W 1
HEATING STAGE 1
W 2
HEATING STAGE 2
O
REVERSING VALVE
G
BLOW ER
R
2 4 V A
C
DHR – DEHUMIDIFICATION RELAY
FIELD INSTALLED
14
Thermostat Outputs
RH
Stat Logic:
Dh- -not energized
Dh - - de- -energized Dh - - energized
ECM CONTROLLER INTERFACE
24V INPUTS
L N I E V O L T S
C
EX: 230VAC
LOW VOLTAGE CLASS II W IRING – 18AW G
A14126
ECM
Board Logic:
HGRH
YES NO
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