Issue:
How to troubleshoot a Traq flow sensor on IntelliPak rooftop units with Symbio 800 Controls
Diagnostics Associated:
Outdoor Airflow Pressure Sensor Alarm - The Outdoor Airflow Pressure sensor has failed out of range.
Airflow Assembly Failure - The unit is configured with Traq and the OA Damper > 50% and the Outdoor Airflow Local <= 0.02 * Design Air Flow for 10 consecutive seconds the diagnostic will be generated.
Invalid Active Outdoor Airflow Unit - No Valid Input from BAS or Unit.
Airflow Press X Measurement Failure where X is “1” or “2” - Calibration Solenoid is not responding correctly.
**Important Note**
There are times when the supply fan is OFF and the Event Log may show Outdoor Air Flow and Duct Static Alarms. These diagnostics are shown because the transducers that monitor these pressure readings will sometimes go below the units configured minimum operating range of 0 CCFM or 0 iwc. Please see Symbio 800 - Nuisance Alarms in Outdoor Air Flow and Duct Static Pressure Alarms in Event Log. If your diagnostic(s) are persistent when the unit is placed in normal operation, please proceed to the following troubleshooting steps.
The airflow measurement station is capable of measuring from 40 CFM/ton to maximum airflow. Outside Airflow setpoints less than 40 CFM/ton will cause nuisance assembly failures and excessive outdoor damper modulation.
Resolution:
How it works:
Whenever the supply fan is on and the fresh air damper is not closed, all of the outside air to the unit flows through 2 or 3 (depending on the unit size) air orifices. Within each orifice is an aluminum flow ring with connections to read the total pressure and static pressure. The flow rings are piped in parallel so that the transducer is reading the average velocity pressure of all of the rings at once. This pressure information is used to calculate the actual airflow through the orifices.
The calibration relay is energized every 60 seconds for about 4 seconds. During calibration the velocity pressure drops to 0" and the controller will take this value as "no flow". At the end of the 4 seconds, the transducer will again read the actual velocity pressure.
Step 1: Determine if the problem is air side or electrical.
Using tee fittings and short pieces of tubing, connect a low range (0-2"WC) or digital manometer to the transducer with the tubes to the flow rings still connected (transducer assembly with purple and yellow tubes). Connect the manometer in parallel to the transducer so that the manometer is reading the same velocity pressure the transducer is seeing from the flow rings. (high port to high port, low port to low port).
Depending on outdoor air flow through the Traq flow rings the pressure should be slightly positive, somewhere between 0.05" and 1.75". When the calibration solenoid is energized, the pressure should drop to 0".
Step 2A, problem is airside:
*If a negative pressure is seen, the tubes from the flow rings may be backward.
*If an extremely high pressure is seen (see chart below), the tubing may be loose, or mis piped at the flow rings.
*If the pressure does not drop to 0" during the calibration mode (every 60 seconds), verify that the relay is actually being energized and that the tubing is clear.
*If the complaint is that the airflow is "always zero", the calibration sequence is suspect.
TRAQ Piezo Tubing Colors
Step 2B, problem is electrical:
Read the DC voltage between the red and green wires at the transducer or 5VDC out and GND at the SPACE PRESSURE/TRAQ Module (J3-1,2). 5VDC should be present. If not, verify that the ribbon connector is connected J11 on the SPACE PRESSURE/TRAQ LLID or if Comm Loss: Space Pressure/Traq is present. If 5VDC is present, proceed with the next test:
Unplug both tubes from the transducer and read the voltage at the black and green wires at the transducer or SIGNAL and GND at the SPACE PRESSURE/TRAQ LLID (J3-2,3). The voltage should be 0.25VDC +- 0.05V. If not, the transducer has failed. If so, reconnect the tubes (with manometer still connected), start the unit, and proceed with the next test:
When the pressure is 0", the output voltage should be ~0.25VDC. As the pressure goes up, the voltage should go up as well. Use this table to see if the pressure and voltage match up.
| Pressure | Typical Voltage |
| 0" | 0.248VDC |
| 0.1" | 0.325VDC |
| 0.2" | 0.400VDC |
| 0.33" | 0.500VDC |
| 1.0" | 1VDC |
The chart shows that as the pressure goes up the voltage goes up, and during calibration the SIGNAL AND GND voltage should drop to 0.25V. The exact values are not important; what is important is that every 60 seconds whatever value is seen during calibration is considered 0" pressure reading and the unit will make all decisions based on this value. If the voltage does not change when the pressure changes, the transducer is bad.
Bottom line:
The problem is usually an air leak, mis piping, or plugged tube. Sometimes the calibration solenoid is bad, and rarely (last choice) the transducer has failed or the SPACE PRESSURE/TRAQ LLID is defective.
Traq Wiring Schematics
IPAK 1 & 3
Ipak 2 will have two Transducers and calibration solenoids on separate LLIDS
TRAQ #1
TRAQ #2
Example of Traq Airflow Transducer Assembly (IPAK 1 Pictured)
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.