NS SPLIT INSTALLATION MANUAL
Troubleshooting
Standard Microprocessor Controls
To check the unit control board for proper operation:
1.Disconnect thermostat wires at the control board.
2.Jumper the desired test input (Y1, Y2, W, O or G) to the R terminal to simulate a thermostat signal.
3.If control functions properly:
•Check for thermostat and field control wiring (use the diagnostic inputs mode).
4.If control responds improperly:
•Ensure that component being controlled is functioning (compressor, blower, reversing valve, etc.).
•Ensure that wiring from control to the component is functioning (refer to the LED Definition table below and use the diagnostic outputs mode).
•If steps above check properly, replace unit control.
LED Definitions and Diagnostics
Standard Microprocessor
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| DIAGNOSTIC MODES |
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LED | DISPLAY MODE | CURRENT | INPUTS | OUTPUTS 1 | OUTPUTS 2 | ||||||||||
| FAULT STATUS | ||||||||||||||
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| Field Selection DIPS |
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| SW2- |
| 1 On | SW2- |
| 1 Off | SW2- |
| 1 NA | SW2- |
| 1 NA | SW2- |
| 1 NA |
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| SW2- |
| 6 On | SW2- |
| 6 On | SW2- |
| 6 Off | SW2- |
| 6 On | SW2- |
| 6 Off |
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| SW2- |
| 7 On | SW2- |
| 7 On | SW2- |
| 7 On | SW2- |
| 7 Off | SW2- |
| 7 Off |
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Drain | Drain Pan Overflow | Drain Pan Overflow |
| Y1 | Compressor |
| Blower | ||||||||
Lockout |
| (On or Low) |
| Low | |||||||||||
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| FP Thermistor (Loop | FP Thermistor (Loop |
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Water Flow | <15º F, Well<30ºF) |
| Y2 |
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<15º F, Well<30ºF) |
| (On or High) | Medium | ||||||||||||
| Lockout |
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High | High Pressure >600 | High Pressure >600 |
| O | Reversing Valve |
| Blower | ||||||||
Pressure | PSI Lockout |
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Low |
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Pressure, | Low Pressure <40 | Low Pressure <40 |
| G | Fan |
| Aux Heat 1 | ||||||||
Current |
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Sensor |
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Airflow | ECM2 RPM <100 | ECM2 RPM <100 |
| W | DHW Pump | Aux Heat 2 | |||||||||
RPM |
| RPM |
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Status | Microprocessor | Not Used |
| SL1 | Loop Pump 1 | Aux Heat 3 | |||||||||
Malfunction |
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DHW Limit | HWL Thermistor | HWL Thermistor | Not Used | Loop Pump 2 | Aux Heat 4 | ||||||||||
>130ºF |
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DHW Off | DHW Pump | DHW Pump Switch Off |
| – | – |
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Switch Off |
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Refrigerant Systems
To maintain sealed circuit integrity, do not install service gauges unless unit operation appears abnormal. Compare the change in temperature on the air side as well as the water side to the tables on pages
Notes: Refrigerant tests must be made with desuperheater turned “OFF”. Verify that air and water flow rates are at proper levels before servicing the refrigerant circuit.
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