Issue:
Space Pressure Sensor Faults
Resolution:
The space static pressure sensor is used on units with 100% exhaust with Statitrac. This diagnostic occurs when the voltage output from the transducer is outside the range for normal building pressures. Normal pressures range from -.67 IWC to .67 IWC. During normal operation if the voltage dips below 0.04 VDC or rises above 0.75 VDC the diagnostic will be generated.
Note: The sensor is capable of responding to pressures from -.75IWC to 9 IWC, but the controls can only read values in the range of -.67 IWC to .67 IWC as valid for space pressure.
This diagnostic can also be generated if the calibration solenoid is not functioning properly. For one second every minute, the calibration solenoid is energized to zero out the transducer. It connects the high port and the low port to outside air static reference. The controls expect to see .53 VDC @ 0.00 IWC during this time. Any difference from this value is used as an error amount and used to adjust the sensor reading for the next minute. If the calibration solenoid is not functioning, the controls will not receive the correct error signal and will interpret the sensor reading as zero pressure. In these cases, if power is cycled to the unit, the sensor will read correctly for one minute and then read decline to 0.00 IWC before giving the diagnostic.
Items to check include:
- wiring
- sensor
- calibration solenoid
- control module (6KF16)
- pneumatic tubing connections
Here are the steps for Intellipak Rooftop
Step #1 Wiring Errors
The space pressure transducer connects to the Space Pressure / TRAQ LLID (6KF16) J2-2 (5 VDC), J2-3 (common) and J2-4 (signal from transducer). Verify that the wiring is correct, all the plugs are connected, and the voltages are present at the transducer. Refer to the unit schematics for wire numbers.
Step #2 Pneumatic Tubing
Refer to above diagram for proper tubing connections for the transducer. Verify that factory installed tubing is correct and there are no air leaks. Also verify that outside air static pressure reference is properly installed. If the outside air static pressure reference is not properly installed, rainwater can enter the tubing. If this is the case, correct the installation and dry out the pneumatic tubing. The customer installed tubing should be connected as shown in the above diagram. If not installed, the sensor will see a large negative pressure when the supply fan is energized and report an error. The customer installed tubing should also be checked for kinks and obstructions. If all appears to be correct, continue to the next step.
Step #3 Sensor Checkout - Invalid Active Space Pressure / Space Pressure Sensor
Tee a manometer/magnehelic into both the high and low ports on the transducer. Verify that the voltage read at J2-2 and J2-3 on the 6KF16 LLID corresponds to the pressure indicated on the manometer using the chart above. If it does not and Steps 1 and 2 have been performed, replace the transducer. If the voltage corresponds to the pressure, proceed to the next step.
Step #4 Calibration Solenoid Checkout - Space Static Press Measurement Failure
The calibration solenoid is energized for one second every minute. During calibration, the 6KF16 should see 0.53 IWC @ 0.00 IWC at pins J2-2 and J2-3. The calibration solenoid's coil voltage is approximately 24VDC and is supplied from the 6KF16 LLID at pins J15-1 and J15-2. If a squeeze bulb is connected the Normally Closed (NC) port and pressurized, it should be relieved for one second every minute. If not, verify that the 6KF16 LLID is supplying the 24 VDC every minute. If not, remove the J15 connector from the 6KF16 and check voltage again. If the 6KF16 is supplying the correct voltage then the solenoid does not function or wiring is shorted. Replace the solenoid and/or check wiring. If the solenoid checks out, proceed to the next step.
Step #5 Control Module
If all the previous steps have been performed, the diagnostic remains, and no errors are found, replace the 6KF16 LLID.
Other Question/Problem/Cause Statements:
| Diagnostic | Condition / Response |
| Space Pressure Sensor | Space Pressure sensor has failed out of range. Statitrac control will be terminated and the Relief Fan Speed and Relief Damper command will fall back to OA Damper Tracking. |
| Invalid Active Space Pressure | No Valid Input from BAS or Unit. Statitrac control will be terminated and the Relief Fan Speed and Relief Damper command will fall back to OA Damper Tracking. |
| Space Static Press Measurement Failure |
Diagnostic triggers if the null voltage delta reported from the sensor while performing zero calibration is greater than the “Max Space Static Press Calibration Limit” Statitrac control will be terminated and the Relief Fan Speed and Relief Damper command will fall back to OA Damper Tracking. |
Facts:
- Intellipak Rooftop 20-130 (S_HM, S_HL)
- Intellipak 2 - 90 - 162 Ton Packaged Rooftop (S_HN)
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.