This is article contains the contents of an operating and troubleshooting presentation for the Symbio 800 IPAK air pressure transducers. The presentation is available for download at the end of the article.
What the Transducer Does
The transducer is comparing one pressure to another pressure:
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Tubing Colors
| Pressure Tubing Description | Tubing Color |
|---|---|
| High Pressure Pre-Evaporated Filter | Blue |
| Low Pressure Pre-Evaporated Filter | Green |
| High Pressure Final Filter | White |
| Low Pressure Final Filter | Black |
| High Pressure Traq | Purple |
| Low Pressure Traq | Yellow |
| Supply Air High | Red |
| Return Air High | Clear |
| Reference Pressure | Orange |
Pressure Transducers
-0.75" to 9" range
-0.2" 5" range
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Calibration Solenoid
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Outside Air Sensing Kit
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Unit Transducer Tubing (Shown with Optional Return Plenum and Space Pressure Transducers)
Traq Fresh Air Measurement
Fresh air measurement
Monitor and control quality of air fresh air entering unit.
How Does a Calibration Solenoid Work
- Transducer measures differential pressure between Hi (pressure source) and Lo (outdoor air reference) ports on the transducer.
- Hi (pressure source) reads through NO and C on Calibration Solenoid.
- Every 57 seconds, the calibration solenoid is energized by a 24VDC powered source for 3 seconds.
- During the calibration sequence the Lo (outside air reference pressure) flows through the NC and C ports on the transducer.
- At this point both the HI and Lo ports on the transducer are reading the same pressure or a 0 iwc. differential pressure.
- VDC reading should at this time should be pretty close to transducer's null voltage reading.
- After 3 second calibration, solenoid de-energizes and the transducer now reads pressure source.
NOTE: Calibration sequence 0 iwc differential pressure will NOT populate as an Active Pressure Reading
Transducer Wiring Examples
Example 1
- Transducer power is 5VDC.
- Mounted to Hex IO.
- i.e. 6KF19
- Supply Air Pressure
- i.e. 6KF19
- Null voltage
- Output voltage at 0" pressure.
- 0.5VDC
- Supply Pressure, Return Plenum Pressure, Space Pressure
- As pressure goes up, output voltage goes up.
Wiring diagram
Transducer Output vs Pressure
Example 2
- Transducer power is 5VDC.
- Mounted to Hex IO
- 6KF16
- Space Pressure/Traq
- Null Voltage
- Output voltage at 0" pressure
- 0.25VDC Traq Fresh Air Measurement
- As pressure goes up, output voltage goes up.
Wiring diagram
Transducer Output vs Pressure
Troubleshooting Transducers
Troubleshooting Duct, Return and Space Pressure Transducers
- Connect a manometer to the transducer as showing, tee in Low port to Lo, High port to Hi
- Watch for calibration solenoid to energize.
- Return to normal reading after calibration.
- MZVAV with Duct Pressure Range setting of High will NOT utilize the Calibration Sequence.
Troubleshooting Traq
- Unit is comparing total pressure with wake pressure.
- Traq flow rings
- Traq flow rings
Troubleshooting Transducers Flowchart
Final Thoughts
- If the transducer output voltage is correct with the tubes disconnected, the transducer is probably good.
- If the transducer output voltage is 0VDC
- Verify power connections
- If the unit says the space pressure or return plenum pressure is 0" but it's not.
- Verify that calibration is working.
- Look for loose or leaking tubing.
- Look for moisture in the tubing.
- Least likely: Bad circuit board, bad transducer, bad calibration solenoid
- Most likely: Tubing problem.