
Page 68
31-5000751 Rev. 0
Outdoor Control Operation, Checkout and Status / Error Codes
OPERATION:
The outdoor control is a microprocessor-based device for use with variable-capacity compressors up to 5-tons in capacity
operating on 24VAC residential power. The outdoor control integrates the functionality of maintaining compressor speed,
and outdoor fan control of ECM motors. The outdoor control is self-configuring. During start-up the outdoor control selects
one of two configurations variable-capacity air conditioner or variable-capacity heat pump.
The NS18HM outdoor control provides application flexibility. The NS18HM may be installed with a conventional 24VAC
single or two stage heat pump thermostat.
RAST TERMINALS FOR
THERMOSTAT WIRING
CONNECTION
CHARGE MODE AND
OPERATION MODE
JUMPER DETAIL
PUSH BUTTON
7 SEGMENT
DISPLAY
OPERATION
MODE
JUMPER
CHARGE
MODE JUMPER
(CHRG MODE)
Figure 41. Outdoor Control Unit
NOTE - System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/dehumidification). Only the latest
active fault or lockout codes are displayed (if present). If no fault or lockout codes are active, then system status codes are displayed. Alert codes are also displayed on the
communicating thermostat.
GF= Gas Furnace, AH=Air Handler, ID=Indoor unit (GF or AH), HP=Heat Pump, AC=Air Conditioner, OD=Outdoor Unit (AC or HP), ZA=Zone system and TS=Thermostat
Alert
Code
Inverter
Flash
Code
Priority
Condition
Actual Displayed
Alert Text
Component or System Operational State and Troubleshooting Tip
How to Clear Alert
Code
125
Service
Urgent
Control Hardware
Problem
There is a hardware problem on a system component control. There is a control hardware
problem.
Replace the control if the problem prevents operation and is persistent.
Automatically clears
five minutes after
the issue no longer
exists.
132
Service
Urgent
Device Control
Software Fault
System component control software is corrupted.
•
Recycle power.
•
If failure re-occurs, replace the system component control.
Manual system
power reset is
required to recover
from this alert code.
601
Information
Only-Dealer
OD Unit Low
Ambient
Operational
Lockout
•
Outdoor unit has been cycled off on low temperature protection.
•
Outdoor unit will not operate when the outdoor ambient is at or below 4°F (-15.6°C).
•
If the unit is satisfying a demand (running) and the outdoor ambient drops below 4°F
(-15.6°C), the unit will continue to operate until the demand has been satisfied or the
outdoor ambient drops to 15°F (-9.4°C) which will result in the unit being locked out
(shut down).
Automatically
clears when low
temperature condition
no longer exists.
Table 21. Outdoor Control 7-Segment Display Alert Codes - Outdoor Control Status