Table 16. Fan Motor Control RPM, LED Code and DC Voltage Output
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|
| CFM Profile Pin Select |
|
| ECM1/Y1 | ||
Model | LED Code* |
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|
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|
| 4 | 3 | 2 | 1 | RPM |
| (J2) DC Volt |
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|
XP17−024 | 5 | OFF | ON | ON | ON | 400 |
| 12.7 |
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|
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|
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|
XP17−030 | 6 | OFF | ON | ON | OFF | 450 |
| 14.3 |
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|
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|
XP17−036, −042 | 8 | OFF | OFF | ON | ON | 600 |
| 19.2 |
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|
XP17−048, −060 | 9 | OFF | OFF | OFF | ON | 675 |
| 21.6 |
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|
* LED Code indicates fan motor control LED flash sequence. For example, LED Code 9 indicates 9 slow flashes and pause.
Table 17. Fan Motor Control Error/Fault LED Codes
Unit Status | Motor Control LED | Possible Cause | |
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|
| |
| Fast flash with no | Internal feedback, | |
Mismatched RPM | PWM does not | ||
pause | |||
| match target | ||
|
| ||
|
|
| |
CRC Failure | Constant ON. | Microcontroller CRC | |
failure | |||
|
| ||
|
|
|
Table 18. 19. Fan Motor Control Stage LED Indicator
Codes
Unit Status | Unit Status | Fan Motor Control | |
LED | |||
|
| ||
|
|
| |
One Stage | Low Stage | One slow flash, then | |
Operation | ECM1/Y1 ONLY | short pause. | |
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|
|
Table 20. Fan Motor Control Flash and Pause
Durations
Flash or Pause State | Duration |
|
|
Flash Flash | Three flashes per second |
|
|
Slow Flash | One flash per second |
|
|
Short Pause | Two seconds of OFF time |
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|
Long Pause | Five seconds of OFF time |
|
|
Testing
Use the following subsections to verify and test the fan motor control (A177).
Verifying Jumper Settings (J2)
The unit is shipped from the factory with the default fan motor speed setting (in RPMs) required for each specific model. Use the table 16 verify that jumpers are set correctly for the specific unit.
Verifying LED Status Codes
During start up, the fan motor control (A177) LED will display any error conditions. If error conditions exist then no other codes will display. If no error conditions are present, then the stage status and and RPM indicator are displayed. Fan motor speeds are not adjustable for a single stage outdoor unit (see table 16).
Verifying Correct DC Output Voltage (J2)
The following three methods can be used to determine whether the fan motor (B4) is operating at the correct RPMs based on unit size.
1.Use the information provided in table 16 to verify that all four jumper terminals are set correctly for the specific size unit.
2.Verify LED RPM indicator is displaying the correct flash sequence for the applicable size unit (see table 18).
3.Test DC voltage output on the fan motor control’s J2 terminals (see figure 34) while under full load and verify the voltage read to the voltage listed in table 16 for the applicable size unit.
4.If no voltage is detected at the J2 terminals, verify there is a Y1 demand at the thermostat and applicable voltages detected all fan motor control (A177) voltage inputs, see table 21.
If there is a demand, proceed to the next section for further testing.
Verifying Correct Input Voltage (ECM/Y1, ECM/Y2,
ECM C and EXT ECM/R)
Using a voltmeter, check voltages on the following fan motor control inputs using table 21. Voltage will only be present during a thermostat demand. See figure 35 for test example.
If correct voltages are detected at applicable inputs during a demand, and no voltage is present at the J2 terminals, then fan motor control should be replaced.
Table 21. Fan Motor Control Voltage Inputs
Input | Call for | Voltage | |
Cooling | Present | ||
| |||
|
|
| |
| YES | Between 24VDC | |
| and 32 VDC | ||
ECM/Y1 and ECM C |
| ||
|
| ||
|
|
| |
| NO | NONE | |
|
|
| |
| YES | 24VAC | |
EXT ECM/R and ECM C |
|
| |
NO | NONE | ||
| |||
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