Johnson Controls 025-29148-102 Pressure Transducer

Johnson Controls has not set a fixed replacement or calibration cycle for this item. It is a condition-monitoring component that is "replaced as needed". The following is the industry standard practice, which is subject to the IOM manual of the unit.
Daily inspection (each inspection). Check for any looseness, water ingress, corrosion of the connection plugs; whether the cable sheaths are damaged; and whether there are oil stains or traces of refrigerant leakage at the interface. If water accumulates on the plugs, it should be dealt with immediately - moisture entering the electrical cavity is the most common failure cause for this type of transmitter.
Quarterly/seasonal inspection. When the unit is operating stably, use a calibrated precision pressure gauge or handheld calibration instrument to measure the pressure at the same point and compare it with the reading on the control panel. The deviation should be within ±0.8% FS (approximately ±0.1 psi); if the deviation varies with temperature or fluctuates greatly, it indicates that the component has aged and should be replaced rather than corrected.
Annual maintenance. Perform two-point calibration: at 0 psi, the output should be approximately 0.5 V, and at full scale, it should be approximately 4.5 V. Use a multimeter to measure the voltage between the signal line and the common terminal, and confirm that the power supply is within the range of 4.75–5.25 V - a low power supply will cause the reading to be overall higher. Insulation resistance and single-point grounding of the shielding layer should also be checked.
Replacement trigger conditions. Replace if there is an output jump or freeze, zero drift exceeds the limit, the panel reports a pressure sensor failure, there is visible damage to the housing or diaphragm, leakage at the sealing area, or any of the above situations occur. This component has been calibrated at the factory, and the zero point and range cannot be adjusted on-site.
Installation precautions. Tighten by clamping the hexagonal body, do not clamp the housing; apply a small amount of refrigerant oil to the O-ring; install the body first and then fix the cable, with the plug outlet facing downward. After replacement, use an independent instrument to verify the reading before putting it into operation, and do not only rely on the panel display.