• An on-board LED to indicate blower CFM.
• Inputs for two-stages of cooling: Y1 (first stage) and Y2 (second stage)
• Four (4) cooling delay profiles
The DIP switches on the interface board are used to define the operation of the ECM motor
(see Table 7).
Refer to Figure 29 for switch identification and factory default settings.
IMPORTANT: Disconnect power to unit when changing DIP switch positions. Even if blower
is not operating, the motor will not recognize changes in DIP switch positions until unit power
is removed and then restored.
B. TRANSFORMER PROTECTION
The ECM interface board is equipped with an automotive-style 3 amp ATC blade fuse for
transformer protection. (See Figure 28.) If a short circuit occurs on the secondary side of the
transformer, the fuse will open.
C. USING THE ON-BOARD LED TO DETERMINE BLOWER CFM
The ECM interface board LED, which is located in the blower section (see Figure 28), indi-
cates blower output by flashing one (1) second for every 100 CFM of airflow. The LED will
pause 1/10 second between each flash. After the blower CFM has been displayed, the LED
will illuminate dimly for 10 seconds before repeating the sequence. (See Table 8.)
NOTE: If airflow is not a multiple of 100 CFM, the last LED flash is a fraction of a second of
100 CFM.
FIGURE 29
ECM MOTOR SETTINGS
(This board is located in the blower section)
TABLE 7
SWITCH FUNCTIONS
Switch Function
1 & 2 Not Used
3 & 4 Cooling Airflow Adjustment
5 & 6 Heating Airflow Settings
7 & 8 Cooling Delay Profiles
9 & 10 On-Demand Dehumidification
FIGURE 28
ECM INTERFACE BOARD
LED
FIRST-STAGE COOLING INPUT SECOND-STAGE COOLING INPUT
(THIS BOARD IS LOCATED IN THE BLOWER SECTION)
DO NOT WIRE DIRECTLY TO THIS BOARD. THERMOSTAT SHOULD
BE WIRED TO PIGTAILS LOCATED BELOW THE CONTROL BOX.
37
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