Chapter 9 Troubleshooting
Table 20. Fan does not energize (Continued)
Probable cause
Unit configuration
Manual output test
Table 21. Valves remain closed
Probable cause
Unit wiring
Failed end device
Normal operation
Requested mode off
Manual output test
Diagnostic present
Entering water
temperature
sampling logic
Unit configuration
Valve configuration
No power to the con-
troller
Table 22. Valves remain open
Probable cause
Unit wiring
Failed end device
Normal operation
68
The controller must be properly configured based on the actual installed end devices and
application (1 heat/1 cool or water-source heat pump). If the unit configuration does not
match the actual end device, the valves may not work correctly.
The controller includes a manual output test sequence you can use to verify output oper-
ation and associated output wiring. However, based on the current step in the test
sequence, the unit fan may not be on. Refer to the "Manual output test" on page 58.
The wiring between the controller outputs and the valve(s) must be present and correct
for normal valve operation. Refer to applicable wiring diagram.
The valves must be checked to ensure proper operation.
The controller opens and closes the valves to meet the unit capacity requirements.
You can communicate a desired operating mode (such as off, heat, and cool) to the con-
troller. If off is communicated to the controller, the unit controls the fan off. There is no
heating or cooling.
The controller includes a manual output test sequence you can use to verify output oper-
ation and associated output wiring. However, based on the current step in the test
sequence, the valves may not be open. Refer to the "Manual output test" on page 58.
A specific list of diagnostics affects valve operation, dependent on whether the unit is
configured as 1 heat/1 cool or a water-source heat pump. For more information, see
Table 18 on page 62 and Table 19 on page 64.
The controller includes entering water temperature sampling logic, which is automati-
cally initiated during 2-pipe and 4-pipe changeover if the entering water temperature is
either too cool or too hot for the desired heating or cooling. (See "AI1: Entering water
temperature sampling" on page 37.)
The controller must be properly configured based on the actual installed end devices and
application (1 heat/1 cool or water-source heat pump). If the unit configuration does not
match the actual end device, the valves may not work correctly.
Make sure the valves are correctly configured, using the Rover service tool, as normally
open or normally closed as dictated by the application.
If the controller does not have power, the unit valve(s) will not operate. For the ZN511
controller to operate normally, you must apply an input voltage of 24 Vac. If the green
LED is off continuously, the controller does not have sufficient power or has failed.
The wiring between the controller outputs and the valve(s) must be present and correct
for normal valve operation. Refer to applicable wiring diagram.
The valves must be checked to ensure proper operations.
The controller opens and closes the valves to meet the unit capacity requirements.
Explanation
Explanation
Explanation
CNT-SVX06B-EN
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