32
NSZ/NDZ INSTALLATION MANUAL
Standard Microprocessor Controls
To check the unit control board for proper operation:
Disconnect thermostat wires at the control board.
1.
Jumper the desired test input (Y1, Y2, W, O or G) to the
2.
R terminal to simulate a thermostat signal.
If control functions properly:
3.
Check for thermostat and field control wiring (use
•
the diagnostic inputs mode).
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 Operating Parameters tables. If the unit’s
performance is not within the ranges listed, and the airflow
and water flow are known to be correct, gauges should
then be installed and superheat and subcooling numbers
calculated. If superheat and subcooling are outside
recommended ranges, an adjustment to the refrigerant
charge may be necessary.
NOTES:
Refrigerant tests must be made with hot water
generator turned “OFF”. Verify that air and water flow rates
are at proper levels before servicing the refrigerant circuit.
LED
NORMAL
DISPLAY MODE
DIAGNOSTIC MODES
CURRENT
FAULT STATUS
INPUTS
OUTPUTS 1
OUTPUTS 2
Field Selection DIPS
SW2-
1 On
SW2-
1 Off
SW2-
1 NA
SW2-
1 NA
SW2-
1 NA
SW2-
6 On
SW2-
6 On
SW2-
6 Off
SW2-
6 On
SW2-
6 Off
SW2-
7 On
SW2-
7 On
SW2-
7 On
SW2-
7 Off
SW2-
7 Off
Drain
Drain Pan Overflow
Lockout
Drain Pan Overflow
Y1
Compressor
(On or Low)
Blower
Low
Water Flow
FD Thermistor
(Loop <15° F,
Well<30°F) Lockout
FD Thermistor
(Loop <15° F,
Well<30°F)
Y2
Compressor
(On or High)
Blower
Medium
High
Pressure
High Pressure >600
PSI Lockout
High Pressure >600
O
Reversing Valve
Blower
High
Low
Pressure,
Current
Sensor
Low Pressure <40
Low Pressure <40
G
Fan
Aux Heat 1
Airflow
ECM2 RPM <100
RPM
ECM2 RPM <100
RPM
W
DHW Pump
Aux Heat 2
Status
Microprocessor
Malfunction
Not Used
SL1
Loop Pump 1
Aux Heat 3
DHW Limit
HWL Thermistor
>130°F
HWL Thermistor
>130°F
Not Used
Loop Pump 2
Aux Heat 4
DHW Off
DHW Pump
Switch Off
DHW Pump Switch
Off
–
–
–
LED Definitions and Diagnostics
Standard Microprocessor
Troubleshooting
If control responds improperly:
4.
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.
•
