Step 10- Operate Ecm Interface Board; Heating; Cfm Adjust; Dehumidification Mode - Carrier PTV Installation, Start-Up And Service Instructions Manual

Step 10 -- Operate ECM Interface Board
The ECM fan is controlled by an interface board that converts
thermostat inputs and field selectable cfm settings to signals
used by the ECM (electronically colmnutated motor) control-
ler. See Fig. 35.
NOTE: Power must be offto the unit for at least three seconds
before the ECM 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).
Tables 9-13 indicate settings for the ECM interface board, fol-
lowed by detailed reformation for each setting.
When the disconnect switch is closed, high voltage is
present in some areas of the electrical panel. Exercise cau-
tion when working with energized equipment.
COOLING--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.
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. See Table 9.
Table 9 -- Cooling Settings
TAP SETTING
1
2
3
4
DIP SWITCH
SWl
ON
ON
OFF
OFF
SW2
ON
OFF
ON
OFF
HEATING -- The heating setting determines the heating cfm
for 50PTH,PTV, PTD units. Tap 1 is the lowest cfm setting,
while tap 4 is the highest cfm setting. See Table 10.
Table 10- Heating Settings
TAP SETTING
1
2
3
4
SW3
ON
ON
OFF
OFF
DIP SWITCH
SW4
ON
OFF
ON
OFF
CFM ADJUST -- The CFM Adjust setting allows four selec-
tions. The NORM setting is the factory default position. The +
or- settings adjust the airflow by ±15%. The + or- settings are
used to "fine rune" airflow adjusUnents. The TEST setting runs
the ECM at 70% torque, which causes the motor to operate
like a standard PSC motor, and disables the cfm counter. See
Table 11.
Table 11 -- CFM Adjust Settings
TAP SETTING
TEST
+
NORM
SW7
ON
ON
OFF
OFF
DIP SWITCH
SW8
ON
OFF
ON
OFF
DEHUMIDIFICATION MODE --The dehumidification
mode setting provides field selection of humidity control.
When operating in the normal mode, the cooling airflow set-
tings are determined by the cooling tap setting in Table 12.
Table 12 -- Dehumidificaton Mode Settings
TAP SETTING
NORM
Dehumid
DIP SWITCH
SW9
ON
OFF
When dehumidification is enabled, there is a reduction in
airflow in cooling to increase the moisture removal of the heat
pump. The Dehumidification mode can be enabled in two
ways:
1. Constant Dehumidification mode: When the Dehumidifi-
cation mode is selected via DIP switch, the ECM will
operate with a multiplier applied to the cooling CFM
settings (approximately 20 to 25% lower airflow). Any
time the unit is running in the Cooling mode, it will oper-
ate at the lower airflow to improve latent capacity. The
"DEHUM" LED will be illuminated at all thnes. Heating
airflow is not affected.
2.
NOTE: Do not select Dehumidification mode if cooling
setting is tap 1.
Automatic (humidistat-controlled) Dehumidification
mode: When the Dehumidification mode is selected
via DIP switch AND a humidistat is connected to termi-
nal DH, the cooling airflow will only be reduced when
the humidistat senses that additional dehumidification is
required. The DH terminal is reverse logic. Therefore,
a humidistat (not dehumidistat) is required. The
"DEHUM" LED will be illuminated only when the humi-
distat is calling for Dehumidification mode. Heating
airflow is not affected.
NOTE: Do not select Dehumidification mode if cooling
setting is tap 1.
I_'ISPADE
CONNECTIONS
TO COMPLETE C OR_
DELUXE D BOARD
THERMOSTAT
CONNECTIONS
\
\
DEHUMIDIFICATIQN
LED
=<
M
r_ u_u_r__ocou_u_ r_
P_
f
/
J
FAN SPEED SELECTION DIP SWITCH
THERMOSTAT
INPUT LEDS
CFM COUNTER
1 FLASH PER 100 CFM
ECM MOTOR
LOW VOLTAGE
CONNECTOR
Fig. 35 -- ECM Interface Board Physical Layout
3O