Operating Instructions

Chapter 5—Troubleshooting
5-16 Siemens Building Technologies, Inc.
C. AIR VOLUME (Point 35) reads a very low value or zero.
1. Verify that the correct value is entered for DUCT AREA (Point 97). If the value is
incorrect, enter the correct value.
2. Check the sensor connections. Repipe if HI and LO connections are reversed.
3. If using an Autozero Module, check that the HI and LO connections are correct and
that the module is wired to DO 4 (terminals 2 and 3) on the ATEC. Repipe or rewire
as needed.
4. Check for leakage near where the sensor tubing enters the duct. Block off any air
leaks using tape or other approved material as required.
5. Verify that DMPR ROT ANG (Point 56) is correctly set. If the setting for this point is
smaller than the damper’s actual rotation angle, then the air velocity sensor may
have been calibrated with the damper open. If the value is incorrect, enter the
correct value, then recalibrate the sensor by setting CAL AIR (Point 97) to YES.
When calibration is finished, CAL AIR automatically returns to NO.
6. Check for pinched, disconnected, or cracked sensor tubing. Correct as needed.
7. Verify that the flow coefficient, as supplied by the air balancer, is entered correctly
for FLOW COEFF (Point 36). If the value is incorrect, enter the correct value.
8. Clean or replace the air velocity sensor and tubing (located in the duct).
9. Contact your local Siemens Building Technologies representative.
D. AIR VOLUME (Point 35) in the application shows an incorrect value.
1. Check for pinched, disconnected, or cracked sensor tubing. Correct as needed.
2. Check to ensure that the sensor is upstream of the damper blade. If not, contact
your local Siemens Building Technologies representative to relocate the sensor.
3. Check that damper seals properly and does not leak when closed.
4. Check for leakage near where the sensor tubing enters the duct. Block off any air
leaks using tape or other approved material as required.
5. If using an Autozero Module, check that the HI and LO connections are correct and
that the module is wired to DO 4 (terminals 2 and 3) on the ATEC. Repipe or rewire
as needed.
6. Verify that the flow coefficient, as supplied by the air balancer, is entered correctly
for FLOW COEFF (Point 36). If the value is incorrect, enter the correct value.
7. Clean or replace the air velocity sensor and tubing (located in the duct).
8. Contact your local Siemens Building Technologies representative.