© 2005 D 420 - 06/05 22 of 24
Error Message Description
BOILER SENSOR OPEN CIRCUIT
Due to an open circuit, the control failed to read the boiler sensor. The control no longer
controls the boiler. Instead, the control provides a boiler enable to the boiler’s aquastat or boiler
control until the sensor is repaired. The control will not operate the boiler contact if the Boil
Minimum setting is less than 100°F (38.0°C). Locate and repair the problem as described in
the Data Brochure D 070. Once the error is corrected, press any button to clear the control.
If you deliberately remove the boiler sensor, set the Boiler Sensor Return / Supply DIP switch
to Return. Power down for 10 seconds then restart the control.
OUTDOOR SENSOR SHORT CIRCUIT
Due to a short circuit, the control failed to read the outdoor sensor. As a result, the control
assumes an outdoor temperature of 32°F (0.0°C) and continues operation. Locate and repair
the problem as described in the Data Brochure D 070. Once the error is corrected, press any
button to clear the error.
OUTDOOR SENSOR OPEN CIRCUIT
Due to an open circuit, the control failed to read the outdoor sensor. As a result, the control
assumes an outdoor temperature of 32°F (0.0°C) and continues operation. Locate and repair
the problem as described in the Data Brochure D 070. Once the error is corrected, press any
button to clear the error.
DEV SCHD
The selected system schedule is no longer available. Either the system schedule master is
no longer connected to the network or the system schedule number has been changed on
the schedule master.
ERROR ON DEVICE B:AA
A tN4 device has an error. B is the bus number. AA is the address of the tN4 device that has
an error on the display. Boiler zones have a bus number of b. If there is more than one device
error, the highest priority error will be displayed. Once the error is cleared on the tN4 device,
the error message will clear automatically.
Error Messages (2 of 2)
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