Document No. 125-1902
User Guide
June 26, 2018
Siemens Industry, Inc.
Page 15 of 16
Symptom
Reason
Solution
Free Cooling LED is solid
RED
Mixed Air (MA) sensor error
Check the MA sensor, it must be either a 10K Type II NTC, or 3K NTC
sensor.
Outside Air (OA)/Return Air
(RA) sensor error
Check the OA sensor. If in DIFF mode, check the RA sensor too. The
following sensor signals are valid:
• 10K Type II NTC temperature
• 3K NTC temperature
• 0–10V temperature and 0–10V humidity
• 10K Type II NTC temperature and 0-10V humidity
• 3K NTC temperature and 0-10V humidity
In Differential (DIFF) mode, OA and RA sensors must be of the same
sensor type.
MIN POS potentiometer has
been damaged by excessive
force
Check if
MIN POS
potentiometer has been damaged; if so, replace the
Economizer Controller.
Sensor Auto Detection error
Ensure that the sensors have been correctly wired prior to controller
power-up. Power-up the active sensors first, or power-up the controller
and the active sensors simultaneously. Otherwise, the controller may not
capture the sensor type in time.
Don’t change the DIP switch settings (10K/3K or SNGL/DIFF) when the
controller is running. The controller must be rebooted after any changes to
the sensor or sensor setting for the new sensor configuration to be
implemented.
DCV LED is solid RED
CO2 sensor error
Check the CO2 sensor signal; the valid signal must be 0-10V.
DCV ACT
or
DCT SET
potentiometer has been
damaged by excessive force
Check if
DCV ACT
or
DCT SET
potentiometer has been damaged by
excessive force; if so, replace the Economizer Controller.
DCV ACT
is not being
turned to the
0
position
The DCV feature should not be enabled, but it was not turned off. Adjust
the DCV ACT potentiometer to full CCW position if you are not using
DCV.
Exhaust Fan LED is not
working
The Ex FAN potentiometer
hasn’t been set up correctly,
or has been damaged by
excessive force.
In its full CCW position, the
EX FAN
control is disabled; therefore, the
Exhaust Fan LED is OFF, and the EF relay is inactive. To use this feature,
the
EX FAN
potentiometer must be turned to a non-zero position.
If the
EX FAN
control is enabled, but the Exhaust Fan
doesn’t work
correctly, check if the
EX FAN
potentiometer has been damaged. If so,
replace the Economizer Controller.
Both Free Cooling and DCV
red LEDs are blinking
The Economizer Controller
is set to COMM mode
The Economizer Controller is set to COMM mode, and must be set back
to AUTO mode to resume normal operation.
DCV red LED is blinking
The DCV feature is enabled,
but the
DCV ACT
potentiometer is improperly
set.
Ensure that the DCV ACT is greater than the MIN POS setting.
The controller has no alarm,
but the Free Cooling LED
never turns on even though
the OA seems to be suitable
for Free Cooling
Shut-off SP setting error
The shut-off temperature and/or enthalpy setpoint is incorrectly set up.
Consult an HVAC professional to set up the shut-off setpoint correctly.
OA temp is too low
The OAT is too low; therefore, there is no cooling demand. This could
possibly enable anti-freeze protection.
OA temp is too high or too
humid
In DIFF mode, even though OA temperature is lower than RA
temperature, if both OA and RA temperatures exceed the high limit, Free
Cooling will turn off.
In Differential Enthalpy control mode, even though OA enthalpy is lower
than RA enthalpy, if both OA and RA enthalpy exceed the high limit, Free
Cooling will turn off.
